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
58.com Inc ADR COM 31680q104 167,584 3,011,396 SH   SOLE   3,011,396 0 0
Affiliated Managers Group Inc COM 008252108 2,804 17,268 SH   SOLE   17,268 0 0
Align Technology Inc. COM 016255101 3,957 54,433 SH   SOLE   54,433 0 0
Allergan PLC COM g0177j108 274,880 1,025,555 SH   SOLE   1,025,555 0 0
Alphabet Inc Cl A COM 02079K305 322,402 422,601 SH   SOLE   422,601 0 0
Alphabet Inc. Cl C COM 02079K107 357,327 479,665 SH   SOLE   479,665 0 0
Altria Group Inc COM 02209S103 4,780 76,284 SH   SOLE   76,284 0 0
American Electric Power COM 025537101 1,028 15,485 SH   SOLE   15,485 0 0
American Express COM 025816109 78,409 1,277,020 SH   SOLE   1,277,020 0 0
Apple Computer COM 037833100 1,171 10,746 SH   SOLE   10,746 0 0
Applied Materials COM 038222105 289 13,632 SH   SOLE   13,632 0 0
Arch Capital Group Ltd COM g0450a105 675 9,488 SH   SOLE   9,488 0 0
AT&T Inc COM 00206r102 3,529 90,085 SH   SOLE   90,085 0 0
Athenahealth Inc. COM 04685w103 27,756 200,000 SH   SOLE   200,000 0 0
Autohome Inc ADR COM 05278c107 2,809 100,550 SH   SOLE   100,550 0 0
Automatic Data Processing COM 053015103 420 4,678 SH   SOLE   4,678 0 0
Bank of America Corp COM 060505104 146 10,807 SH   SOLE   10,807 0 0
Bed Bath & Beyond Inc COM 075896100 298 6,000 SH   SOLE   6,000 0 0
Berkshire Hathaway - Cl A COM 084670108 1,832,682 8,586 SH   SOLE   8,586 0 0
Berkshire Hathaway - Cl B COM 084670702 672,195 4,737,770 SH   SOLE   4,737,770 0 0
Brown & Brown Inc. COM 115236101 48,574 1,356,829 SH   SOLE   1,356,829 0 0
Cabelas Inc. Cl A COM 126804301 127,385 2,616,239 SH   SOLE   2,616,239 0 0
Cable One Inc. COM 12685J105 1,411 3,228 SH   SOLE   3,228 0 0
Canadian Natural Resources COM 136385101 18,630 689,985 SH   SOLE   689,985 0 0
Caterpillar COM 149123101 5,232 68,356 SH   SOLE   68,356 0 0
ChevronTexaco Corp COM 166764100 411 4,305 SH   SOLE   4,305 0 0
Chipotle Mexican Grill Inc COM 169656105 44,215 93,880 SH   SOLE   93,880 0 0
Coca Cola Co. COM 191216100 11,060 238,417 SH   SOLE   238,417 0 0
Colfax Corp COM 194014106 14,335 501,400 SH   SOLE   501,400 0 0
Colgate Palmolive Co. COM 194162103 262 3,715 SH   SOLE   3,715 0 0
Comcast Corp. Cl A COM 20030n101 521 8,532 SH   SOLE   8,532 0 0
Consolidated Edison Inc. COM 209111103 228 2,974 SH   SOLE   2,974 0 0
Costco Wholesale Corp COM 22160k105 109,231 693,177 SH   SOLE   693,177 0 0
Cresud SACIFYA Spon ADR Repstg COM 226406106 7,125 612,147 SH   SOLE   612,147 0 0
CVS Corp. COM 126650100 1,658 15,981 SH   SOLE   15,981 0 0
Danaher Corp. COM 235851102 130,773 1,378,586 SH   SOLE   1,378,586 0 0
Demandware Inc. COM 24802Y105 9,115 233,130 SH   SOLE   233,130 0 0
Dentsply Sirona Inc. COM 24906P109 298,494 4,843,324 SH   SOLE   4,843,324 0 0
Disney Walt COM 254687106 2,551 25,686 SH   SOLE   25,686 0 0
Du Pont E I De Nemours & Co. COM 263534109 248 3,912 SH   SOLE   3,912 0 0
Edison International COM 281020107 3,084 42,900 SH   SOLE   42,900 0 0
Emcor Group Inc COM 29084q100 74,007 1,522,781 SH   SOLE   1,522,781 0 0
Emerson Electric COM 291011104 242 4,443 SH   SOLE   4,443 0 0
Expeditors Int'l of Wash. Inc. COM 302130109 2,455 50,289 SH   SOLE   50,289 0 0
Exxon Mobil Corp COM 30231g103 6,496 77,716 SH   SOLE   77,716 0 0
Fastenal Co COM 311900104 902,196 18,412,172 SH   SOLE   18,412,172 0 0
Federal Home Loan Mortgage Cor COM 313400301 2,010 1,500,000 SH   SOLE   1,500,000 0 0
Federal National Mortgage Assn COM 313586109 2,313 1,651,820 SH   SOLE   1,651,820 0 0
Fifth Third Bancorp COM 316773100 1,867 111,881 SH   SOLE   111,881 0 0
General Electric COM 369604103 6,790 213,603 SH   SOLE   213,603 0 0
Goldman Sachs Group Inc COM 38141g104 111,180 708,242 SH   SOLE   708,242 0 0
Graham Holdings Co. COM 384637104 1,549 3,228 SH   SOLE   3,228 0 0
HDFC Bank Ltd ADR Repstg 3 Shs COM 40415f101 989 16,047 SH   SOLE   16,047 0 0
Heartland Express COM 422347104 1,875 101,057 SH   SOLE   101,057 0 0
Home Depot COM 437076102 3,523 26,403 SH   SOLE   26,403 0 0
IAC Interactivecorp COM 44919P508 56,740 1,205,190 SH   SOLE   1,205,190 0 0
IBM COM 459200101 112,413 742,244 SH   SOLE   742,244 0 0
Idexx Laboratories Corp. COM 45168D104 600,572 7,668,176 SH   SOLE   7,668,176 0 0
Interactive Brokers Group Inc COM 45841n107 39,396 1,001,923 SH   SOLE   1,001,923 0 0
Jacobs Engineering Group Inc COM 469814107 248,816 5,713,337 SH   SOLE   5,713,337 0 0
JD.com COM 47215P106 45,925 1,733,000 SH   SOLE   1,733,000 0 0
Johnson & Johnson COM 478160104 1,507 13,925 SH   SOLE   13,925 0 0
JP Morgan Chase & Co. COM 46625h100 1,103 18,625 SH   SOLE   18,625 0 0
Kraft Heinz Co. COM 500754106 1,359 17,301 SH   SOLE   17,301 0 0
Lennox International Inc. COM 526107107 1,479 10,938 SH   SOLE   10,938 0 0
Leucadia Nat'l COM 527288104 266 16,471 SH   SOLE   16,471 0 0
Liberty Global PLC Shrs CL A COM g5480u104 6,278 163,073 SH   SOLE   163,073 0 0
Liberty Lilac Group CL C COM g5480u153 3,225 85,150 SH   SOLE   85,150 0 0
Linear Technology Group COM 535678106 4,942 110,899 SH   SOLE   110,899 0 0
Linkedin Corp Cl A COM 53578a108 3,593 31,425 SH   SOLE   31,425 0 0
LKQ Corp. COM 501889208 5,173 162,000 SH   SOLE   162,000 0 0
Lockheed Martin Corp. COM 539830109 528 2,385 SH   SOLE   2,385 0 0
Lowe's Companies Inc. COM 548661107 696 9,194 SH   SOLE   9,194 0 0
Makemytrip Ltd COM v5633w109 50,902 2,813,802 SH   SOLE   2,813,802 0 0
Mastercard Inc COM 57636q104 489,789 5,182,954 SH   SOLE   5,182,954 0 0
Match Group Inc. COM 57665r106 7,756 701,250 SH   SOLE   701,250 0 0
McDonalds COM 580135101 8,577 68,246 SH   SOLE   68,246 0 0
McGraw Hill COM 580645109 380 3,840 SH   SOLE   3,840 0 0
Medtronic PLC COM G5960L103 292 3,895 SH   SOLE   3,895 0 0
Merck & Co. COM 58933y105 259 4,894 SH   SOLE   4,894 0 0
Microsoft COM 594918104 3,198 57,904 SH   SOLE   57,904 0 0
Mohawk Industries COM 608190104 500,565 2,622,133 SH   SOLE   2,622,133 0 0
Mondelez International COM 50075n104 2,162 53,882 SH   SOLE   53,882 0 0
Monsanto Co COM 61166w101 51,549 587,518 SH   SOLE   587,518 0 0
Novo Nordisk A/S ADR COM 670100205 5,285 97,525 SH   SOLE   97,525 0 0
O Reilly Automotive Inc COM 67103h107 790,985 2,890,395 SH   SOLE   2,890,395 0 0
Och Ziff Capital Management Gr COM 67551U105 3,263 750,000 SH   SOLE   750,000 0 0
Omnicom Group COM 681919106 223,607 2,686,613 SH   SOLE   2,686,613 0 0
PepsiCo COM 713448108 4,568 44,578 SH   SOLE   44,578 0 0
Perrigo Co PLC COM G97822103 187,032 1,461,985 SH   SOLE   1,461,985 0 0
Pfizer COM 717081103 369 12,442 SH   SOLE   12,442 0 0
Philip Morris Intl Inc. COM 718172109 8,817 89,869 SH   SOLE   89,869 0 0
Pioneer Natural Resources Co. COM 723787107 394 2,802 SH   SOLE   2,802 0 0
Praxair COM 74005P104 198,427 1,733,744 SH   SOLE   1,733,744 0 0
Price T Rowe Group Inc COM 74144t108 201 2,740 SH   SOLE   2,740 0 0
Primerica Inc COM 74164M108 128,360 2,882,551 SH   SOLE   2,882,551 0 0
Procter & Gamble COM 742718109 8,051 97,819 SH   SOLE   97,819 0 0
Progressive Corp. Ohio COM 743315103 1,750 49,798 SH   SOLE   49,798 0 0
Public Storage Inc. COM 74460d109 687 2,492 SH   SOLE   2,492 0 0
Range Resources Corp COM 75281a109 191,354 5,909,630 SH   SOLE   5,909,630 0 0
Resource America Inc - (RESTRI COM 761195205 1,697 294,117 SH   SOLE   294,117 0 0
Resource America Inc Cl A COM 761195205 3,480 603,180 SH   SOLE   603,180 0 0
Robert Half Internat'l COM 770323103 326 7,000 SH   SOLE   7,000 0 0
Roper Industries Inc New COM 776696106 299 1,635 SH   SOLE   1,635 0 0
Royal Dutch Shell PLC Spon ADR COM 780259206 865 17,848 SH   SOLE   17,848 0 0
Ryanair Holdings PLC ADR COM 783513104 465 5,422 SH   SOLE   5,422 0 0
Schlumberger Ltd COM 806857108 2,634 35,713 SH   SOLE   35,713 0 0
Sherwin Williams Co. COM 824348106 684 2,402 SH   SOLE   2,402 0 0
Soufun Holdings LTD ADR COM 836034108 6,041 1,008,500 SH   SOLE   1,008,500 0 0
Stericycle Inc. COM 858912108 379 3,000 SH   SOLE   3,000 0 0
Suntrust Banks COM 867914103 1,115 30,906 SH   SOLE   30,906 0 0
Third Point Reinsurance LTD COM g8827u100 34,449 3,029,800 SH   SOLE   3,029,800 0 0
Tiffany & Co COM 886547108 152,330 2,075,900 SH   SOLE   2,075,900 0 0
Time Warner Cable Inc. COM 88732j207 6,920 33,817 SH   SOLE   33,817 0 0
Time Warner Inc COM 887317303 11,193 154,280 SH   SOLE   154,280 0 0
TJX Cos - New COM 872540109 1,267,989 16,183,648 SH   SOLE   16,183,648 0 0
Trimble Navigation Ltd. COM 896239100 76,689 3,092,288 SH   SOLE   3,092,288 0 0
U.S. Bancorp New - Del. COM 902973304 855 21,064 SH   SOLE   21,064 0 0
Union Pacific COM 907818108 5,205 65,426 SH   SOLE   65,426 0 0
Valeant Pharmaceuticals Intern COM 91911k102 797,112 30,308,449 SH   SOLE   30,308,449 0 0
Verisk Analytics Class A COM 92345Y106 4,453 55,719 SH   SOLE   55,719 0 0
Verizon Communications COM 92343v104 223 4,121 SH   SOLE   4,121 0 0
Vipshop Hldgs Ltd ADR COM 92763w103 15,842 1,230,000 SH   SOLE   1,230,000 0 0
Visa Inc Class A COM 92826C839 242,964 3,176,837 SH   SOLE   3,176,837 0 0
Wal-Mart Stores COM 931142103 134,882 1,969,373 SH   SOLE   1,969,373 0 0
Waters Corp COM 941848103 253,384 1,920,738 SH   SOLE   1,920,738 0 0
Wells Fargo & Co. New COM 949746101 4,464 92,300 SH   SOLE   92,300 0 0
West Pharmaceutical Svcs Inc C COM 955306105 36,993 533,650 SH   SOLE   533,650 0 0
Woodward Inc COM 980745103 541 10,401 SH   SOLE   10,401 0 0
WPP PLC New ADR COM 92937a102 331 2,840 SH   SOLE   2,840 0 0
Yandex NV Shs COM n97284108 55,205 3,603,475 SH   SOLE   3,603,475 0 0
Yelp Inc. COM 985817105 11,735 590,300 SH   SOLE   590,300 0 0
Zoetis Inc. COM 98978v103 5,620 126,783 SH   SOLE   126,783 0 0
JP Morgan Chase & Co Exp 10/28 WAR 46634e114 24,780 1,400,000 SH   SOLE   1,400,000 0 0