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
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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
3M Company COM 88579y101 299 2,106 SH   SOLE   2,106 0 0
58.com Inc ADR COM 31680q104 148,127 3,148,295 SH   SOLE   3,148,295 0 0
AT&T Inc COM 00206r102 3,062 93,994 SH   SOLE   93,994 0 0
Align Technology Inc. COM 016255101 4,016 70,747 SH   SOLE   70,747 0 0
Allergan PLC COM g0177j108 299,914 1,103,395 SH   SOLE   1,103,395 0 0
Alphabet Inc Cl A COM 02079K305 342,704 536,843 SH   SOLE   536,843 0 0
Alphabet Inc. Cl C COM 02079K107 356,114 585,310 SH   SOLE   585,310 0 0
Altria Group Inc COM 02209S103 4,166 76,574 SH   SOLE   76,574 0 0
American Electric Power COM 025537101 880 15,485 SH   SOLE   15,485 0 0
American Express COM 025816109 102,209 1,378,780 SH   SOLE   1,378,780 0 0
Amgen COM 031162100 279 2,017 SH   SOLE   2,017 0 0
Apple Computer COM 037833100 1,579 14,316 SH   SOLE   14,316 0 0
Applied Materials COM 038222105 201 13,692 SH   SOLE   13,692 0 0
Arch Capital Group Ltd COM g0450a105 785 10,688 SH   SOLE   10,688 0 0
Athenahealth Inc. COM 04685w103 26,670 200,000 SH   SOLE   200,000 0 0
Automatic Data Processing COM 053015103 501 6,238 SH   SOLE   6,238 0 0
Bank of America Corp COM 060505104 321 20,580 SH   SOLE   20,580 0 0
Bed Bath & Beyond Inc COM 075896100 346 6,075 SH   SOLE   6,075 0 0
Berkshire Hathaway - Cl A COM 084670108 1,837,989 9,414 SH   SOLE   9,414 0 0
Berkshire Hathaway - Cl B COM 084670702 640,823 4,914,288 SH   SOLE   4,914,288 0 0
Bio-Techne Corp COM 09073m104 235 2,540 SH   SOLE   2,540 0 0
Boeing COM 097023105 234 1,790 SH   SOLE   1,790 0 0
Bristol-Myers Squibb COM 110122108 217 3,670 SH   SOLE   3,670 0 0
Brown & Brown Inc. COM 115236101 80,551 2,600,933 SH   SOLE   2,600,933 0 0
CVS Corp. COM 126650100 2,407 24,953 SH   SOLE   24,953 0 0
Cabelas Inc. Cl A COM 126804301 155,685 3,414,145 SH   SOLE   3,414,145 0 0
Cable One Inc. COM 12685J105 1,366 3,256 SH   SOLE   3,256 0 0
Canadian Natural Resources COM 136385101 14,652 753,298 SH   SOLE   753,298 0 0
Caterpillar COM 149123101 4,476 68,479 SH   SOLE   68,479 0 0
Chemours Co. COM 163851108 72 11,150 SH   SOLE   11,150 0 0
ChevronTexaco Corp COM 166764100 405 5,140 SH   SOLE   5,140 0 0
Chubb COM 171232101 273 2,222 SH   SOLE   2,222 0 0
Citigroup Inc COM 172967424 298 6,016 SH   SOLE   6,016 0 0
Coca Cola Co. COM 191216100 27,265 679,583 SH   SOLE   679,583 0 0
Cognizant Technology Solutions COM 192446102 205 3,279 SH   SOLE   3,279 0 0
Colfax Corp COM 194014106 14,997 501,400 SH   SOLE   501,400 0 0
Colgate Palmolive Co. COM 194162103 236 3,715 SH   SOLE   3,715 0 0
Comcast Corp. Spl Cl A COM 20030n200 428 7,474 SH   SOLE   7,474 0 0
ConocoPhillips COM 20825c104 3,798 79,200 SH   SOLE   79,200 0 0
Costco Wholesale Corp COM 22160k105 110,645 765,336 SH   SOLE   765,336 0 0
Cresud SACIFYA Spon ADR Repstg COM 226406106 5,987 612,147 SH   SOLE   612,147 0 0
Danaher Corp. COM 235851102 123,283 1,446,814 SH   SOLE   1,446,814 0 0
Disney Walt COM 254687106 2,850 27,891 SH   SOLE   27,891 0 0
Du Pont E I De Nemours & Co. COM 263534109 2,688 55,762 SH   SOLE   55,762 0 0
Edison International COM 281020107 2,706 42,900 SH   SOLE   42,900 0 0
Emcor Group Inc COM 29084q100 71,903 1,624,935 SH   SOLE   1,624,935 0 0
Emerson Electric COM 291011104 221 5,005 SH   SOLE   5,005 0 0
Expeditors Int'l of Wash. Inc. COM 302130109 5,388 114,519 SH   SOLE   114,519 0 0
Express Scripts Holding Co. COM 30219g108 397 4,905 SH   SOLE   4,905 0 0
Exxon Mobil Corp COM 30231g103 6,431 86,491 SH   SOLE   86,491 0 0
Fastenal Co COM 311900104 879,729 24,029,751 SH   SOLE   24,029,751 0 0
Fifth Third Bancorp COM 316773100 2,165 114,508 SH   SOLE   114,508 0 0
General Electric COM 369604103 5,574 221,026 SH   SOLE   221,026 0 0
Goldman Sachs Group Inc COM 38141g104 219,655 1,264,129 SH   SOLE   1,264,129 0 0
Graham Holdings Co. COM 384637104 1,879 3,256 SH   SOLE   3,256 0 0
Greenlight Capital Re Ltd Cl A COM G4095J109 7,288 327,131 SH   SOLE   327,131 0 0
Groupon Inc. COM 399473107 9,789 3,002,617 SH   SOLE   3,002,617 0 0
HDFC Bank Ltd ADR Repstg 3 Shs COM 40415f101 1,120 18,328 SH   SOLE   18,328 0 0
Heartland Express COM 422347104 2,015 101,057 SH   SOLE   101,057 0 0
Hexcel Corp COM 428291108 89,847 2,002,840 SH   SOLE   2,002,840 0 0
Home Depot COM 437076102 3,399 29,428 SH   SOLE   29,428 0 0
IAC Interactivecorp COM 44919p300 58,751 900,115 SH   SOLE   900,115 0 0
IBM COM 459200101 197,168 1,360,062 SH   SOLE   1,360,062 0 0
Idex Corp COM 45167R104 373 5,225 SH   SOLE   5,225 0 0
Idexx Laboratories Corp. COM 45168D104 606,420 8,167,274 SH   SOLE   8,167,274 0 0
Innerworkings Inc Com COM 45773y105 3,442 550,796 SH   SOLE   550,796 0 0
Interactive Brokers Group Inc COM 45841n107 39,565 1,002,415 SH   SOLE   1,002,415 0 0
Ishares India 50 ETF COM 464289529 214 7,674 SH   SOLE   7,674 0 0
JP Morgan Chase & Co. COM 46625h100 1,434 23,514 SH   SOLE   23,514 0 0
Jacobs Engineering Group Inc COM 469814107 227,582 6,080,212 SH   SOLE   6,080,212 0 0
Johnson & Johnson COM 478160104 7,132 76,400 SH   SOLE   76,400 0 0
Jumei International ADR COM 48138l107 3,606 365,337 SH   SOLE   365,337 0 0
Kinder Morgan Inc. COM 49456b101 267 9,630 SH   SOLE   9,630 0 0
Kraft Heinz Co. COM 500754106 1,227 17,378 SH   SOLE   17,378 0 0
LKQ Corp. COM 501889208 5,672 200,000 SH   SOLE   200,000 0 0
Lennox International Inc. COM 526107107 2,142 18,897 SH   SOLE   18,897 0 0
Leucadia Nat'l COM 527288104 334 16,471 SH   SOLE   16,471 0 0
Liberty Lilac Group CL C COM g5480u153 2,916 85,150 SH   SOLE   85,150 0 0
Linear Technology Group COM 535678106 5,113 126,713 SH   SOLE   126,713 0 0
Lockheed Martin Corp. COM 539830109 528 2,545 SH   SOLE   2,545 0 0
Lowe's Companies Inc. COM 548661107 653 9,477 SH   SOLE   9,477 0 0
MRC Global Inc. COM 55345k103 17,254 1,547,405 SH   SOLE   1,547,405 0 0
Makemytrip Ltd COM v5633w109 34,523 2,510,750 SH   SOLE   2,510,750 0 0
Mastercard Inc COM 57636q104 490,563 5,443,441 SH   SOLE   5,443,441 0 0
McDonalds COM 580135101 13,484 136,852 SH   SOLE   136,852 0 0
McGraw Hill COM 580645109 332 3,840 SH   SOLE   3,840 0 0
Medtronic PLC COM G5960l103 340 5,075 SH   SOLE   5,075 0 0
Merck & Co. COM 58933y105 247 4,994 SH   SOLE   4,994 0 0
Microsoft COM 594918104 2,600 58,749 SH   SOLE   58,749 0 0
Mohawk Industries COM 608190104 506,497 2,786,164 SH   SOLE   2,786,164 0 0
Mondelez International COM 50075n104 2,367 56,542 SH   SOLE   56,542 0 0
Monsanto Co COM 61166w101 82,216 963,396 SH   SOLE   963,396 0 0
Novo Nordisk A/S ADR COM 670100205 4,411 81,320 SH   SOLE   81,320 0 0
O Reilly Automotive Inc COM 67103h107 895,904 3,583,615 SH   SOLE   3,583,615 0 0
Omnicom Group COM 681919106 186,368 2,828,039 SH   SOLE   2,828,039 0 0
PepsiCo COM 713448108 17,521 185,803 SH   SOLE   185,803 0 0
Perrigo Co PLC COM G97822103 231,111 1,469,515 SH   SOLE   1,469,515 0 0
Pfizer COM 717081103 355 11,302 SH   SOLE   11,302 0 0
Philip Morris Intl Inc. COM 718172109 7,231 91,153 SH   SOLE   91,153 0 0
Phillips 66 COM 718546104 3,046 39,637 SH   SOLE   39,637 0 0
Pioneer Natural Resources Co. COM 723787107 481 3,952 SH   SOLE   3,952 0 0
Praxair COM 74005P104 189,657 1,861,936 SH   SOLE   1,861,936 0 0
Precision Castparts Corp COM 740189105 811,739 3,533,754 SH   SOLE   3,533,754 0 0
Price T Rowe Group Inc COM 74144t108 281 4,045 SH   SOLE   4,045 0 0
Primerica Inc COM 74164M108 129,917 2,882,551 SH   SOLE   2,882,551 0 0
Procter & Gamble COM 742718109 11,458 159,271 SH   SOLE   159,271 0 0
Progressive Corp. Ohio COM 743315103 1,678 54,768 SH   SOLE   54,768 0 0
Public Storage Inc. COM 74460d109 528 2,493 SH   SOLE   2,493 0 0
Qihoo 360 Technology Co. ADR COM 74734m109 11,570 241,900 SH   SOLE   241,900 0 0
Range Resources Corp COM 75281a109 189,817 5,909,630 SH   SOLE   5,909,630 0 0
Republic Services Inc Cl A COM 760759100 503 12,198 SH   SOLE   12,198 0 0
Resource America Inc - (RESTRI COM 761195205 1,956 294,117 SH   SOLE   294,117 0 0
Resource America Inc Cl A COM 761195205 4,011 603,180 SH   SOLE   603,180 0 0
Robert Half Internat'l COM 770323103 358 7,000 SH   SOLE   7,000 0 0
Roper Industries Inc New COM 776696106 700 4,465 SH   SOLE   4,465 0 0
Royal Bk CDA Montreal Que COM 780087102 2,785 50,400 SH   SOLE   50,400 0 0
Royal Dutch Shell PLC Spon ADR COM 780259206 1,009 21,299 SH   SOLE   21,299 0 0
Schlumberger Ltd COM 806857108 2,691 39,011 SH   SOLE   39,011 0 0
Sherwin Williams Co. COM 824348106 1,182 5,307 SH   SOLE   5,307 0 0
Sirona Dental Systems Inc COM 82966c103 263,817 2,826,405 SH   SOLE   2,826,405 0 0
Soufun Holdings LTD ADR COM 836034108 6,656 1,008,500 SH   SOLE   1,008,500 0 0
Stericycle Inc. COM 858912108 418 3,000 SH   SOLE   3,000 0 0
Suntrust Banks COM 867914103 1,193 31,203 SH   SOLE   31,203 0 0
Symetra Finl Corp COM 87151q106 396 12,500 SH   SOLE   12,500 0 0
TJX Cos - New COM 872540109 1,271,705 17,806,004 SH   SOLE   17,806,004 0 0
Thermo Electron COM 883556102 351 2,873 SH   SOLE   2,873 0 0
Third Point Reinsurance LTD COM g8827u100 40,751 3,029,800 SH   SOLE   3,029,800 0 0
Tiffany & Co COM 886547108 167,236 2,165,713 SH   SOLE   2,165,713 0 0
Time Warner Cable Inc. COM 88732j207 25,812 143,904 SH   SOLE   143,904 0 0
Time Warner Inc COM 887317303 280 4,078 SH   SOLE   4,078 0 0
Trimble Navigation Ltd. COM 896239100 54,622 3,326,578 SH   SOLE   3,326,578 0 0
U.S. Bancorp New - Del. COM 902973304 1,066 25,999 SH   SOLE   25,999 0 0
Union Pacific COM 907818108 8,916 100,846 SH   SOLE   100,846 0 0
Valeant Pharmaceuticals Intern COM 91911k102 6,051,041 33,922,192 SH   SOLE   33,922,192 0 0
Verisk Analytics Class A COM 92345Y106 4,341 58,730 SH   SOLE   58,730 0 0
Verizon Communications COM 92343v104 250 5,756 SH   SOLE   5,756 0 0
Vipshop Hldgs Ltd ADR COM 92763w103 12,936 770,000 SH   SOLE   770,000 0 0
Visa Inc Class A COM 92826C839 232,503 3,337,678 SH   SOLE   3,337,678 0 0
WPP PLC New ADR COM 92937a102 295 2,840 SH   SOLE   2,840 0 0
Wal-Mart Stores COM 931142103 141,014 2,174,799 SH   SOLE   2,174,799 0 0
Waters Corp COM 941848103 240,954 2,038,353 SH   SOLE   2,038,353 0 0
Wells Fargo & Co. New COM 949746101 12,052 234,700 SH   SOLE   234,700 0 0
West Pharmaceutical Svcs Inc C COM 955306105 54,638 1,009,579 SH   SOLE   1,009,579 0 0
Yandex NV Shs COM n97284108 38,912 3,626,438 SH   SOLE   3,626,438 0 0
Yelp Inc. COM 985817105 2,333 107,700 SH   SOLE   107,700 0 0
Young Broadcasting Inc Cl A COM 987434107 0 144,865 SH   SOLE   144,865 0 0
Zoetis Inc. COM 98978v103 6,428 156,094 SH   SOLE   156,094 0 0
Banco Santander SA ADR COM 05964H105 54 10,277 SH   SOLE   10,277 0 0
Constellation Software Inc. COM 21037x100 182,244 436,754 SH   SOLE   436,754 0 0
Ryanair Hldgs PLC Spon ADR COM 783513104 626 7,989 SH   SOLE   7,989 0 0
Senvest Capital Inc. COM 81731l109 4,000 35,000 SH   SOLE   35,000 0 0