The Securities and Exchange Commission has not necessarily reviewed the information in this filing and has not determined if it is accurate and complete.
The reader should not assume that the information is accurate and complete.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
FORM 13F

FORM 13F INFORMATION TABLE
OMB APPROVAL
OMB Number: 3235-0006
Estimated average burden
hours per response: 23.8
COLUMN 1 COLUMN 2 COLUMN 3 COLUMN 4 COLUMN 5 COLUMN 6 COLUMN 7 COLUMN 8
VALUE SHRS OR SH/ PUT/ INVESTMENT OTHER VOTING AUTHORITY
NAME OF ISSUER TITLE OF CLASS CUSIP (x$1000) PRN AMT PRN CALL DISCRETION MANAGER SOLE SHARED NONE
3D SYSTEMS CORP COM 88554D205 65,538 2,390,162 SH   SOLE   2,390,162 0 0
3M CO COM 88579Y101 707 4,289 SH   SOLE   4,289 0 0
ABBOTT LABORATORIES COM 002824100 528 11,400 SH   SOLE   11,400 0 0
ABBVIE INC COM 00287Y109 510 8,716 SH   SOLE   8,716 0 0
ALTERA CORP COM 021441100 301 7,018 SH   SOLE   7,018 0 0
AMAZON.COM INC COM 023135106 340 915 SH   SOLE   915 0 0
AMBER ROAD INC COM 02318y108 518 56,032 SH   SOLE   56,032 0 0
AMERICAN ADDICTION CENTERS COM 000307108 8,528 278,880 SH   SOLE   278,880 0 0
AMERICAN TOWER CORP COM 03027X100 71,106 755,245 SH   SOLE   755,245 0 0
ANADARKO PETROLEUM CORP COM 032511107 439 5,300 SH   SOLE   5,300 0 0
ANSYS INC COM 03662Q105 179,355 2,033,730 SH   SOLE   2,033,730 0 0
APPLE COMPUTER INC COM 037833100 1,543 12,403 SH   SOLE   12,403 0 0
APPLIED MINERALS COM 03823m100 56 80,000 SH   SOLE   80,000 0 0
ATRION CORP COM 049904105 2,506 7,254 SH   SOLE   7,254 0 0
AUTOMATIC DATA PROCESSING COM 053015103 2,041 23,832 SH   SOLE   23,832 0 0
BEACON ROOFING SUPPLY INC COM 073685109 217 6,939 SH   SOLE   6,939 0 0
BECTON DICKINSON & CO COM 075887109 298 2,075 SH   SOLE   2,075 0 0
BERKSHIRE HATHAWAY INC COM 084670108 1,522 7 SH   SOLE   7 0 0
BERKSHIRE HATHAWAY INC. DEL CL COM 084670702 3,342 23,160 SH   SOLE   23,160 0 0
BIO-TECHNE CORP COM 09073M104 34,734 346,332 SH   SOLE   346,332 0 0
BIOGEN INC COM 09062x103 52,293 123,847 SH   SOLE   123,847 0 0
BLACKBAUD INC COM 09227q100 36,350 767,199 SH   SOLE   767,199 0 0
CAMPBELL SOUP CO COM 134429109 200 4,300 SH   SOLE   4,300 0 0
CANADIAN NATIONAL RAILROAD CO COM 136375102 1,337 20,000 SH   SOLE   20,000 0 0
CAPITAL ONE FINANCIAL COM 14040H105 2,065 26,201 SH   SOLE   26,201 0 0
CARMAX INC COM 143130102 87,836 1,272,805 SH   SOLE   1,272,805 0 0
CELGENE CORP COM 151020104 112,799 978,477 SH   SOLE   978,477 0 0
CHEVRON CORP COM 166764100 1,016 9,680 SH   SOLE   9,680 0 0
CHIPOTLE MEXICAN GRILLE INC COM 169656105 43,909 67,497 SH   SOLE   67,497 0 0
CISCO SYSTEMS INC COM 17275R102 2,110 76,641 SH   SOLE   76,641 0 0
COCA COLA CO COM 191216100 1,065 26,260 SH   SOLE   26,260 0 0
COGNIZANT TECH SOLUTIONS CORP COM 192446102 250 4,000 SH   SOLE   4,000 0 0
COLGATE-PALMOLIVE COM 194162103 693 10,000 SH   SOLE   10,000 0 0
COMCAST CORP - A COM 20030N101 713 12,625 SH   SOLE   12,625 0 0
COMCAST CORP - A - SPL COM 20030N200 3,865 68,934 SH   SOLE   68,934 0 0
CONCHO RESOURCES INC COM 20605P101 65,074 561,372 SH   SOLE   561,372 0 0
CORE LABORATORIES NV COM N22717107 56,610 541,777 SH   SOLE   541,777 0 0
COSTAR GROUP INC. COM 22160n109 85,708 433,243 SH   SOLE   433,243 0 0
CROWN CASTLE INTL CORP COM 22822V101 5,294 64,135 SH   SOLE   64,135 0 0
DEALERTRACK TECHNOLOGIES INC COM 242309102 71,886 1,866,189 SH   SOLE   1,866,189 0 0
DENTSPLY INTL COM 249030107 239 4,700 SH   SOLE   4,700 0 0
DISCOVER FINANCIAL SERVICES COM 254709108 95,420 1,693,353 SH   SOLE   1,693,353 0 0
DONALDSON INC COM 257651109 1,004 26,635 SH   SOLE   26,635 0 0
DOUGLAS DYNAMICS INC COM 25960R105 814 35,633 SH   SOLE   35,633 0 0
DUKE REALTY CORP COM 264411505 321 14,750 SH   SOLE   14,750 0 0
DUPONT E I DE NEMOURS & CO COM 263534109 266 3,718 SH   SOLE   3,718 0 0
EAST WEST BANCORP INC COM 27579R104 344 8,500 SH   SOLE   8,500 0 0
ECOLAB INC COM 278865100 126,170 1,103,073 SH   SOLE   1,103,073 0 0
ELI LILLY & CO COM 532457108 694 9,554 SH   SOLE   9,554 0 0
ELLIE MAE INC COM 28849P100 3,113 56,289 SH   SOLE   56,289 0 0
EMERSON COM 291011104 478 8,450 SH   SOLE   8,450 0 0
ENTERPRISE PRODUCTS PARTNERS L COM 293792107 606 18,400 SH   SOLE   18,400 0 0
ENVESTNET INC COM 29404K106 1,213 21,633 SH   SOLE   21,633 0 0
EQT CORPORATION COM 26884L109 3,508 42,335 SH   SOLE   42,335 0 0
EQUITY RESIDENTIAL PROPERTYS I COM 29476l107 551 7,076 SH   SOLE   7,076 0 0
EXAMWORKS GROUP INC. COM 30066a105 78,209 1,879,127 SH   SOLE   1,879,127 0 0
EXPEDITORS INTERNATIONAL COM 302130109 35,905 745,232 SH   SOLE   745,232 0 0
EXPONENT INC. COM 30214U102 26,571 298,888 SH   SOLE   298,888 0 0
EXPRESS SCRIPTS INC COM 30219G108 1,738 20,029 SH   SOLE   20,029 0 0
EXXON MOBIL CORP COM 30231G102 1,819 21,400 SH   SOLE   21,400 0 0
FASTENAL CO COM 311900104 185,471 4,476,204 SH   SOLE   4,476,204 0 0
FINANCIAL ENGINES INC COM 317485100 61,678 1,474,488 SH   SOLE   1,474,488 0 0
FISERV INC COM 337738108 5,278 66,468 SH   SOLE   66,468 0 0
FORTINET INC COM 34959e109 1,179 33,730 SH   SOLE   33,730 0 0
FREEPORT MCMORAN COPPER & GOLD COM 35671D857 238 12,576 SH   SOLE   12,576 0 0
GENERAL ELECTRIC COM 369604103 3,056 123,190 SH   SOLE   123,190 0 0
GENUINE PARTS COMPANY COM 372460105 349 3,749 SH   SOLE   3,749 0 0
GILEAD SCIENCES INC. COM 375558103 752 7,667 SH   SOLE   7,667 0 0
GOOGLE INC CL C COM 38259P706 261 477 SH   SOLE   477 0 0
GOOGLE INC CLASS A COM 38259P508 250 450 SH   SOLE   450 0 0
GUIDEWIRE SOFTWARE INC COM 40171V100 381 7,239 SH   SOLE   7,239 0 0
HCP INC COM 40414L109 4,402 101,864 SH   SOLE   101,864 0 0
HEALTH CARE REIT INC COM 42217K106 253 3,273 SH   SOLE   3,273 0 0
HEALTHCARE SERVICES GROUP INC COM 421906108 65,642 2,043,026 SH   SOLE   2,043,026 0 0
HESS CORPORATION COM 42809h107 343 5,052 SH   SOLE   5,052 0 0
HOME DEPOT COM 437076102 341 2,999 SH   SOLE   2,999 0 0
ILLINOIS TOOL WORKS COM 452308109 233 2,400 SH   SOLE   2,400 0 0
ILLUMINA INC COM 452327109 18,681 100,629 SH   SOLE   100,629 0 0
IMAX CORP COM 45245E109 93,798 2,782,512 SH   SOLE   2,782,512 0 0
INTEL CORP COM 458140100 13,437 429,707 SH   SOLE   429,707 0 0
INTL BUSINESS MACH CORP COM 459200101 1,770 11,026 SH   SOLE   11,026 0 0
INTUITIVE SURGICAL INC COM 46120e602 65,918 130,523 SH   SOLE   130,523 0 0
INVENTURE FOODS INC COM 461212102 226 20,177 SH   SOLE   20,177 0 0
J P MORGAN CHASE & CO COM 46625H100 313 5,169 SH   SOLE   5,169 0 0
JACOBS ENGINEERING CP INC COM 469814107 317 7,022 SH   SOLE   7,022 0 0
JOHNSON & JOHNSON COM 478160104 10,666 106,026 SH   SOLE   106,026 0 0
KINDER MORGAN INC COM 49455P101 212 5,043 SH   SOLE   5,043 0 0
LABORATORY CORP OF AMERICA HOL COM 50540R409 2,478 19,653 SH   SOLE   19,653 0 0
LINCOLN NATL CORP COM 534187109 318 5,536 SH   SOLE   5,536 0 0
LKQ CORP COM 501889208 148,738 5,819,173 SH   SOLE   5,819,173 0 0
LOWE'S COMPANIES INC COM 548661107 215 2,888 SH   SOLE   2,888 0 0
LYNAS CORP LTD COM Q5683J103 3 75,000 SH   SOLE   75,000 0 0
M&T BANK CORP COM 55261F104 433 3,413 SH   SOLE   3,413 0 0
MACY'S, INC. COM 55616P104 303 4,663 SH   SOLE   4,663 0 0
MAGELLAN MIDSTREAM PARTNERS LP COM 559080106 276 3,600 SH   SOLE   3,600 0 0
MARKEL CORP COM 570535104 134,511 174,926 SH   SOLE   174,926 0 0
MASTERCARD INC CL A COM 57636Q104 2,173 25,150 SH   SOLE   25,150 0 0
McCORMICK & CO COM 579780206 2,776 36,000 SH   SOLE   36,000 0 0
MCGRAW HILL FINANCIAL COM 580645109 16,653 161,053 SH   SOLE   161,053 0 0
MERCK & CO COM 58933Y105 1,214 21,125 SH   SOLE   21,125 0 0
MICROSOFT CORP COM 594918104 2,472 60,801 SH   SOLE   60,801 0 0
MIDDLEBY CORP COM 596278101 1,522 14,823 SH   SOLE   14,823 0 0
MONRO MUFFLER BRAKE COM 610236101 624 9,594 SH   SOLE   9,594 0 0
MOODYS CORP COM 615369105 132,469 1,276,198 SH   SOLE   1,276,198 0 0
NATIONAL AMERICAN UNIV HOLDING COM 63245Q105 49 15,000 SH   SOLE   15,000 0 0
NEOGEN CORP COM 640491106 458 9,800 SH   SOLE   9,800 0 0
O REILLY AUTOMOTIVE INC COM 67103H107 16,032 74,139 SH   SOLE   74,139 0 0
ONEBEACON INSURANCE GP COM G67742109 507 33,306 SH   SOLE   33,306 0 0
OXYSURE SYSTEMS INC COM 69208t101 8 10,000 SH   SOLE   10,000 0 0
PANERA BREAD CO COM 69840W108 5,546 34,665 SH   SOLE   34,665 0 0
PAYCHEX COM 704326107 3,368 67,882 SH   SOLE   67,882 0 0
PEPSICO INC COM 713448108 395 4,135 SH   SOLE   4,135 0 0
PFIZER INC COM 717081103 1,178 33,856 SH   SOLE   33,856 0 0
PHILIP MORRIS INTL COM 718172109 390 5,178 SH   SOLE   5,178 0 0
PINNACLE WEST CAPITOL CORP COM 723484101 312 4,900 SH   SOLE   4,900 0 0
PNC FINANCIAL SVCS INC COM 693475105 2,462 26,406 SH   SOLE   26,406 0 0
POOL CORPORATION COM 73278L105 231 3,313 SH   SOLE   3,313 0 0
POTASH CORP OF SASKATCHEWAN COM 73755L107 24,233 751,421 SH   SOLE   751,421 0 0
PRA GROUP INC COM 69354n106 21,970 404,450 SH   SOLE   404,450 0 0
PRECISION CASTPARTS CORP COM 740189105 378 1,800 SH   SOLE   1,800 0 0
PRICE SMART INC COM 741511109 43,248 508,925 SH   SOLE   508,925 0 0
PROCTER & GAMBLE CO COM 742718109 20,513 250,343 SH   SOLE   250,343 0 0
QUALCOMM INC COM 747525103 107,745 1,553,864 SH   SOLE   1,553,864 0 0
QUALITY DISTRIBUTION INC COM 74756m102 344 33,256 SH   SOLE   33,256 0 0
QUALYS, INC COM 74758T303 237 5,100 SH   SOLE   5,100 0 0
RANGE RESOURCES CORP COM 75281A109 37,751 725,428 SH   SOLE   725,428 0 0
RED HAT INC. COM 756577102 160,522 2,119,101 SH   SOLE   2,119,101 0 0
ROPER TECHNOLOGIES INC COM 776696106 107,197 623,241 SH   SOLE   623,241 0 0
SBA COMMUNICATIONS CORP COM 78388J106 1,723 14,715 SH   SOLE   14,715 0 0
SCHLUMBERGER LTD COM 806857108 33,570 402,321 SH   SOLE   402,321 0 0
SEI INVESTMENTS CO COM 784117103 163,250 3,702,643 SH   SOLE   3,702,643 0 0
SIGNET JEWELERS LTD COM g81276100 127,170 916,277 SH   SOLE   916,277 0 0
SILVER WHEATON CORP COM 828336107 285 15,000 SH   SOLE   15,000 0 0
SMITH & NEPHEW PLC COM 83175M205 256 7,500 SH   SOLE   7,500 0 0
SOTHERLY HOTELS, INC COM 83600C103 104 13,625 SH   SOLE   13,625 0 0
SOUTHWESTERN ENERGY CO COM 845467109 382 16,465 SH   SOLE   16,465 0 0
STERICYCLE INC COM 858912108 119,727 852,577 SH   SOLE   852,577 0 0
STRATASYS LTD COM M85548101 30,756 582,715 SH   SOLE   582,715 0 0
T ROWE PRICE GROUP INC COM 74144T108 13,911 171,786 SH   SOLE   171,786 0 0
TANGOE INC COM 87582Y108 48,562 3,518,959 SH   SOLE   3,518,959 0 0
TRIMBLE NAVIGATION LTD COM 896239100 99,034 3,929,912 SH   SOLE   3,929,912 0 0
TYLER TECHNOLOGIES INC COM 902252105 56,914 472,200 SH   SOLE   472,200 0 0
U.S. BANCORP COM 902973304 1,416 32,436 SH   SOLE   32,436 0 0
ULTIMATE SOFTWARE INC COM 90385d107 294 1,730 SH   SOLE   1,730 0 0
UNDER ARMOUR, INC COM 904311107 606 7,500 SH   SOLE   7,500 0 0
UNION PACIFIC CORP COM 907818108 265 2,450 SH   SOLE   2,450 0 0
UNITED TECHNOLOGIES CORP COM 913017109 511 4,364 SH   SOLE   4,364 0 0
VENTAS INC COM 92276f100 2,709 37,106 SH   SOLE   37,106 0 0
VERISK ANALYTICS COM 92345Y106 110,681 1,550,156 SH   SOLE   1,550,156 0 0
VERIZON COMMUNICATIONS COM 92343V104 211 4,329 SH   SOLE   4,329 0 0
VF CORP COM 918204108 301 4,000 SH   SOLE   4,000 0 0
VISA INC COM 92826C839 126,657 1,936,362 SH   SOLE   1,936,362 0 0
WAGEWORKS INC COM 930427109 95,838 1,797,084 SH   SOLE   1,797,084 0 0
WALT DISNEY CO COM 254687106 1,003 9,564 SH   SOLE   9,564 0 0
WASTE CONNECTIONS INC COM 941053100 84,552 1,756,373 SH   SOLE   1,756,373 0 0
WATSCO INC CL A COM 942622200 830 6,600 SH   SOLE   6,600 0 0
WELLS FARGO & CO COM 949746101 329 6,055 SH   SOLE   6,055 0 0
WHOLE FOODS MARKET COM 966837106 788 15,134 SH   SOLE   15,134 0 0
WR BERKLEY CORP COM 084423102 2,665 52,753 SH   SOLE   52,753 0 0
WSFS FINANCIAL CORPORATION COM 929328102 588 7,775 SH   SOLE   7,775 0 0
XOOM CORPORATION COM 98419Q101 1,314 89,462 SH   SOLE   89,462 0 0
ZOE'S KITCHEN INC COM 98979J109 345 10,358 SH   SOLE   10,358 0 0
VANGUARD DIVIDEND ETFS 921908844 954 11,850 SH   SOLE   11,850 0 0
VANGUARD FTSE ALL-WORLD EX-US ETFS 922042775 2,853 58,547 SH   SOLE   58,547 0 0
VANGUARD FTSE EMERGING MARKETS ETFS 922042858 528 12,925 SH   SOLE   12,925 0 0
VANGUARD HIGH DIVIDEND YIELD E ETFS 921946406 354 5,185 SH   SOLE   5,185 0 0
VANGUARD INDEX REIT ETF ETFS 922908553 477 5,655 SH   SOLE   5,655 0 0