DF Dent & Co 13F-HR Quarterly holdings report by institutional manager

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
3-D SYS CORP DEL COM NEW	COM	88554D205	521	38,940	SH		SOLE		38,940	0	0
3M COMPANY	COM	88579y101	1,402	6,680	SH		SOLE		6,680	0	0
AAC HOLDINGS INC	COM	000307108	10,298	1,037,024	SH		SOLE		1,037,024	0	0
ABBOTT LABORATORIES	COM	002824100	590	11,066	SH		SOLE		11,066	0	0
ABBVIE INC SHS	COM	00287y109	683	7,682	SH		SOLE		7,682	0	0
AIR PRODUCTS & CHEMICALS, INC.	COM	009158106	275	1,820	SH		SOLE		1,820	0	0
ALPHABET INC CLASS C	COM	02079K107	88,388	92,156	SH		SOLE		92,156	0	0
ALPHABET INC. CLASS A	COM	02079k305	945	971	SH		SOLE		971	0	0
AMAZON.COM INC	COM	023135106	55,287	57,510	SH		SOLE		57,510	0	0
AMERICAN TOWER REIT INC	COM	03027X100	90,074	659,016	SH		SOLE		659,016	0	0
AMGEN INC COM PV $0.0001	COM	031162100	262	1,406	SH		SOLE		1,406	0	0
ANSYS INC	COM	03662Q105	149,459	1,217,784	SH		SOLE		1,217,784	0	0
APPLE INC	COM	037833100	1,403	9,103	SH		SOLE		9,103	0	0
ATRION CORPORATION	COM	049904105	6,300	9,375	SH		SOLE		9,375	0	0
AUTOMATIC DATA PROC	COM	053015103	1,655	15,138	SH		SOLE		15,138	0	0
BALL CORP	COM	058498106	224	5,435	SH		SOLE		5,435	0	0
BEACON ROOFING SUPPLY INC	COM	073685109	1,261	24,599	SH		SOLE		24,599	0	0
BECTON DICKINSON&CO	COM	075887109	289	1,475	SH		SOLE		1,475	0	0
BERKLEY W R CORP	COM	084423102	3,157	47,308	SH		SOLE		47,308	0	0
BERKSHIRE HATHAWAY INC DELAWA	COM	084670108	1,648	6	SH		SOLE		6	0	0
BERKSHIRE HATHAWAYINC DEL CL	COM	084670702	3,957	21,587	SH		SOLE		21,587	0	0
BIO-TECHNE CORP	COM	09073M104	47,839	395,727	SH		SOLE		395,727	0	0
BLACKBAUD INC	COM	09227Q100	59,616	678,997	SH		SOLE		678,997	0	0
BLACKLINE	COM	09239B109	77,466	2,270,403	SH		SOLE		2,270,403	0	0
BRIGHT HORIZONS FAM SOL IN DEL	COM	109194100	967	11,215	SH		SOLE		11,215	0	0
CALAVO GROWERS INC	COM	128246105	621	8,489	SH		SOLE		8,489	0	0
CANADIAN NATL RY CO COM	COM	136375102	1,657	20,000	SH		SOLE		20,000	0	0
CAPITAL ONE FINL CORP COM	COM	14040H105	2,049	24,204	SH		SOLE		24,204	0	0
CARMAX INC	COM	143130102	116,673	1,539,022	SH		SOLE		1,539,022	0	0
CARRIAGE SERVICES, INC.	COM	143905107	803	31,379	SH		SOLE		31,379	0	0
CARTER'S INC	COM	146229109	454	4,602	SH		SOLE		4,602	0	0
CBRE GROUP INC	COM	12504L109	39,541	1,043,847	SH		SOLE		1,043,847	0	0
CELGENE CORP	COM	151020104	119,542	819,793	SH		SOLE		819,793	0	0
CHEVRON CORP	COM	166764100	759	6,456	SH		SOLE		6,456	0	0
CISCO SYSTEMS INC COM	COM	17275r102	2,226	66,196	SH		SOLE		66,196	0	0
COCA COLA COM	COM	191216100	1,632	36,263	SH		SOLE		36,263	0	0
COGENT COMMUNICATIONS	COM	19239V302	1,735	35,481	SH		SOLE		35,481	0	0
COGNIZANT TECHNOLOGY SOLUTIONS	COM	192446102	290	4,000	SH		SOLE		4,000	0	0
COLFAX CORPORATION	COM	194014106	669	16,055	SH		SOLE		16,055	0	0
COLGATE-PALMOLIVE CO	COM	194162103	723	9,925	SH		SOLE		9,925	0	0
COMCAST CORP NEW CL A	COM	20030n101	4,095	106,406	SH		SOLE		106,406	0	0
COMPUTER MODELLING LTD	COM	205249105	177	24,220	SH		SOLE		24,220	0	0
COMPUTER MODELLING LTD	COM	205249105	278	38,020	SH		SOLE		38,020	0	0
CONOCOPHILLIPS	COM	20825c104	214	4,284	SH		SOLE		4,284	0	0
CORELOGIC INC	COM	21871D103	1,396	30,206	SH		SOLE		30,206	0	0
COSTAR GROUP INC	COM	22160N109	88,801	331,040	SH		SOLE		331,040	0	0
CROWN CASTLE REIT INC SHS	COM	22822v101	6,635	66,363	SH		SOLE		66,363	0	0
DEXCOM INC	COM	252131107	3,711	75,856	SH		SOLE		75,856	0	0
DISCOVER FINANCIAL SERVICES (U	COM	254709108	49,681	770,490	SH		SOLE		770,490	0	0
DISNEY (WALT) CO COM STK	COM	254687106	1,067	10,826	SH		SOLE		10,826	0	0
DOLLAR GENERAL	COM	256677105	233	2,874	SH		SOLE		2,874	0	0
DOUGLAS DYNAMICS INC	COM	25960R105	2,502	63,511	SH		SOLE		63,511	0	0
DOWDUPONT INC	COM	26078j100	376	5,435	SH		SOLE		5,435	0	0
DUKE REALTY CORP REIT	COM	264411505	330	11,450	SH		SOLE		11,450	0	0
DULUTH HOLDINGS INC	COM	26443V101	402	19,798	SH		SOLE		19,798	0	0
EAST WEST BANCORP INC	COM	27579r104	448	7,500	SH		SOLE		7,500	0	0
ECOLAB INC	COM	278865100	154,448	1,200,905	SH		SOLE		1,200,905	0	0
EDWARDS LIFESCIENCES	COM	28176e108	1,468	13,431	SH		SOLE		13,431	0	0
ELI LILLY & CO	COM	532457108	719	8,408	SH		SOLE		8,408	0	0
ELLIE MAE INC	COM	28849P100	4,108	50,017	SH		SOLE		50,017	0	0
EMERSON ELECTRIC CO	COM	291011104	795	12,659	SH		SOLE		12,659	0	0
ENTERPRISE PRDTS PRTN LPL P	COM	293792107	448	17,175	SH		SOLE		17,175	0	0
ENVESTNET INC	COM	29404K106	67,339	1,320,368	SH		SOLE		1,320,368	0	0
EQUITY RESIDENTIAL REIT	COM	29476l107	371	5,626	SH		SOLE		5,626	0	0
EVERTEC INC	COM	30040P103	436	27,519	SH		SOLE		27,519	0	0
EXPONENT INC	COM	30214U102	30,156	408,061	SH		SOLE		408,061	0	0
EXPRESS SCRIPTS HLDG	COM	30219g108	1,009	15,941	SH		SOLE		15,941	0	0
EXXON MOBIL CORP COM	COM	30231g102	1,624	19,805	SH		SOLE		19,805	0	0
FACEBOOK INC CLASS	COM	30303m102	316	1,850	SH		SOLE		1,850	0	0
FASTENAL CO	COM	311900104	89,483	1,963,207	SH		SOLE		1,963,207	0	0
FISERV INC	COM	337738108	8,712	67,553	SH		SOLE		67,553	0	0
FORTINET INC COM	COM	34959E109	368	10,263	SH		SOLE		10,263	0	0
GENERAL ELECTRIC	COM	369604103	2,815	116,422	SH		SOLE		116,422	0	0
GENESEE AND WYO INC CL A	COM	371559105	11,025	148,965	SH		SOLE		148,965	0	0
GENUINE PARTS CO	COM	372460105	480	5,023	SH		SOLE		5,023	0	0
GLACIER BANCORP INC NEW	COM	37637Q105	821	21,730	SH		SOLE		21,730	0	0
GUIDEWIRE SOFTWARE INC	COM	40171V100	1,396	17,925	SH		SOLE		17,925	0	0
HCP INC	COM	40414l109	1,427	51,271	SH		SOLE		51,271	0	0
HEALTHCARE SERVICES GROUP INC	COM	421906108	80,996	1,500,765	SH		SOLE		1,500,765	0	0
HEALTHSTREAM INC	COM	42222N103	522	22,332	SH		SOLE		22,332	0	0
HEICO CORP NEW CL A	COM	422806208	1,681	22,056	SH		SOLE		22,056	0	0
HOME DEPOT INC	COM	437076102	415	2,536	SH		SOLE		2,536	0	0
HONEYWELL INTL INC	COM	438516106	215	1,520	SH		SOLE		1,520	0	0
IBM CORP	COM	459200101	1,026	7,070	SH		SOLE		7,070	0	0
IDEXX LABORATORIES INC	COM	45168D104	19,036	122,429	SH		SOLE		122,429	0	0
ILLINOIS TOOL WORKS	COM	452308109	303	2,050	SH		SOLE		2,050	0	0
ILLUMINA INC	COM	452327109	96,917	486,530	SH		SOLE		486,530	0	0
IMAX CORP	COM	45245E109	15,853	699,911	SH		SOLE		699,911	0	0
INTEL CORP	COM	458140100	12,344	324,149	SH		SOLE		324,149	0	0
INTUITIVE SURGICAL INC	COM	46120E602	137,574	131,539	SH		SOLE		131,539	0	0
JOHN BEAN TECHNOLOGIES	COM	477839104	641	6,339	SH		SOLE		6,339	0	0
JOHNSON AND JOHNSON COM	COM	478160104	11,018	84,747	SH		SOLE		84,747	0	0
JPMORGAN CHASE & CO	COM	46625h100	409	4,280	SH		SOLE		4,280	0	0
KEYON COMMUNI HOLD INC	COM	493312201	0	16,667	SH		SOLE		16,667	0	0
KIMBERLY CLARK	COM	494368103	278	2,363	SH		SOLE		2,363	0	0
LABORATORY CORP AMER HLDGS COM	COM	50540R409	2,693	17,837	SH		SOLE		17,837	0	0
LCI INDUSTRIES	COM	50189K103	579	4,996	SH		SOLE		4,996	0	0
LIBERTY TRIPADVISOR HLDGS INC	COM	531465102	268	21,717	SH		SOLE		21,717	0	0
LINCOLN NTL CORP IND NPV	COM	534187109	820	11,155	SH		SOLE		11,155	0	0
LITHIA MOTORS INC CL A	COM	536797103	1,175	9,765	SH		SOLE		9,765	0	0
LITTELFUSE INC	COM	537008104	487	2,486	SH		SOLE		2,486	0	0
LKQ CORP	COM	501889208	93,492	2,597,715	SH		SOLE		2,597,715	0	0
M & T BANK CORP	COM	55261f104	664	4,126	SH		SOLE		4,126	0	0
MAGELLAN MIDSTREAM PRTNRS LP C	COM	559080106	256	3,600	SH		SOLE		3,600	0	0
MARKEL CORP HLDG CO	COM	570535104	99,180	92,867	SH		SOLE		92,867	0	0
MARKETAXESS HLDGS INC COM	COM	57060D108	482	2,610	SH		SOLE		2,610	0	0
MASTERCARD INC-CLASS A	COM	57636Q104	68,080	482,152	SH		SOLE		482,152	0	0
MCCORMICK & CO INC COM NON VTG	COM	579780206	1,349	13,139	SH		SOLE		13,139	0	0
MERCK AND CO INC SHS	COM	58933y105	1,537	24,011	SH		SOLE		24,011	0	0
MESA LABS INC	COM	59064R109	1,573	10,536	SH		SOLE		10,536	0	0
MICROSOFT CORP	COM	594918104	4,123	55,354	SH		SOLE		55,354	0	0
MIDDLEBY CORP	COM	596278101	2,637	20,571	SH		SOLE		20,571	0	0
MONRO INC	COM	610236101	1,456	25,974	SH		SOLE		25,974	0	0
MOODYS CORP	COM	615369105	133,849	961,489	SH		SOLE		961,489	0	0
MSC INDUSTRIAL DIRECT CO INC C	COM	553530106	333	4,407	SH		SOLE		4,407	0	0
NASPERS SPON ADR EACH REP 0.2	COM	631512209	536	12,400	SH		SOLE		12,400	0	0
NATIONAL AMERICAN UNIVER	COM	63245q105	32	15,000	SH		SOLE		15,000	0	0
NEOGEN CORP COM	COM	640491106	759	9,800	SH		SOLE		9,800	0	0
NESTLE S A REP RG SH ADR	COM	641069406	498	5,942	SH		SOLE		5,942	0	0
NORFOLK SOUTHERN CO	COM	655844108	302	2,285	SH		SOLE		2,285	0	0
O REILLY AUTOMOTIVE INC	COM	67103H107	12,694	58,940	SH		SOLE		58,940	0	0
PAYCHEX INC	COM	704326107	3,328	55,511	SH		SOLE		55,511	0	0
PEPSICO INC	COM	713448108	637	5,713	SH		SOLE		5,713	0	0
PFIZER INC	COM	717081103	1,056	29,567	SH		SOLE		29,567	0	0
PHILIP MORRIS INTL	COM	718172109	392	3,533	SH		SOLE		3,533	0	0
PINNACLE WEST CAP CORP	COM	723484101	254	3,000	SH		SOLE		3,000	0	0
PIONEER NAT RES CO COM	COM	723787107	214	1,449	SH		SOLE		1,449	0	0
PNC FINCL SERVICES GROUP	COM	693475105	2,411	17,888	SH		SOLE		17,888	0	0
POOL CORPORATION	COM	73278l105	345	3,188	SH		SOLE		3,188	0	0
POTASH CORP SASKATCHEWAN	COM	73755l107	590	30,650	SH		SOLE		30,650	0	0
PRA GROUP INC	COM	69354N106	245	8,539	SH		SOLE		8,539	0	0
PRICE T ROWE GROUP INC	COM	74144T108	12,896	142,264	SH		SOLE		142,264	0	0
PROASSURANCE CORP	COM	74267C106	323	5,908	SH		SOLE		5,908	0	0
PROCTER & GAMBLE CO	COM	742718109	15,303	168,203	SH		SOLE		168,203	0	0
PROS HOLDINGS INC	COM	74346Y103	65,219	2,702,800	SH		SOLE		2,702,800	0	0
QUALCOMM INC	COM	747525103	19,841	382,740	SH		SOLE		382,740	0	0
RED HAT INC	COM	756577102	168,032	1,515,714	SH		SOLE		1,515,714	0	0
REXNORD CORP	COM	76169B102	621	24,429	SH		SOLE		24,429	0	0
ROPER TECHNOLOGIES INC	COM	776696106	164,278	674,931	SH		SOLE		674,931	0	0
RPM INTERNATIONAL INC	COM	749685103	225	4,385	SH		SOLE		4,385	0	0
S & P GLOBAL INC	COM	78409V104	85,097	544,415	SH		SOLE		544,415	0	0
SBA COMMUNICATIONS CORP CL A	COM	78410G104	27,437	190,466	SH		SOLE		190,466	0	0
SCHLUMBERGER LTD	COM	806857108	6,360	91,173	SH		SOLE		91,173	0	0
SEI INVESTMENTS CO	COM	784117103	140,816	2,306,183	SH		SOLE		2,306,183	0	0
SIGNET JEWELERS LTD	COM	G81276100	685	10,286	SH		SOLE		10,286	0	0
SITEONE	COM	82982L103	408	7,028	SH		SOLE		7,028	0	0
SMITH & NEPHEW P L C ADS	COM	83175M205	393	10,800	SH		SOLE		10,800	0	0
SOTHERLY HOTELS INC COM	COM	83600C103	68	11,625	SH		SOLE		11,625	0	0
SPS COMMERCE INC	COM	78463M107	357	6,296	SH		SOLE		6,296	0	0
STERIS PLC	COM	G84720104	66,609	753,492	SH		SOLE		753,492	0	0
TELADOC INC	COM	87918A105	1,700	51,293	SH		SOLE		51,293	0	0
TESLA INC	COM	88160R101	231	676	SH		SOLE		676	0	0
THE DESCARTES SYSTEMS GROUP IN	COM	249906108	480	17,561	SH		SOLE		17,561	0	0
TRANSDIGM GROUP INC	COM	893641100	60,673	237,330	SH		SOLE		237,330	0	0
TRIMBLE INC	COM	896239100	95,690	2,437,973	SH		SOLE		2,437,973	0	0
TYLER TECHNOLOGIES INC	COM	902252105	104,614	600,129	SH		SOLE		600,129	0	0
U S BANCORP	COM	902973304	1,638	30,560	SH		SOLE		30,560	0	0
ULTIMATE SOFTWARE GROUP INC	COM	90385D107	528	2,787	SH		SOLE		2,787	0	0
UNITED PARCEL SERVICE INC CL B	COM	911312106	377	3,136	SH		SOLE		3,136	0	0
UNITED TECHS CORP COM	COM	913017109	467	4,020	SH		SOLE		4,020	0	0
VENTAS INC REIT	COM	92276f100	1,917	29,432	SH		SOLE		29,432	0	0
VERISK ANALYTICS INC	COM	92345Y106	119,693	1,438,792	SH		SOLE		1,438,792	0	0
VERIZON COMMUNICATNS COM	COM	92343v104	457	9,231	SH		SOLE		9,231	0	0
VISA INC CL A	COM	92826C839	144,651	1,374,489	SH		SOLE		1,374,489	0	0
W.P. CAREY INC. REIT	COM	92936u109	342	5,074	SH		SOLE		5,074	0	0
WABTEC	COM	929740108	275	3,626	SH		SOLE		3,626	0	0
WAGEWORKS INC	COM	930427109	102,627	1,690,718	SH		SOLE		1,690,718	0	0
WASTE CONNECTIONS INC	COM	94106B101	102,097	1,459,368	SH		SOLE		1,459,368	0	0
WATSCO INC COM	COM	942622200	69,280	430,125	SH		SOLE		430,125	0	0
WAYFAIR	COM	94419L101	566	8,391	SH		SOLE		8,391	0	0
WD-40 COMPANY	COM	929236107	656	5,860	SH		SOLE		5,860	0	0
WELLS FARGO & CO	COM	949746101	422	7,659	SH		SOLE		7,659	0	0
WELLTOWER INC	COM	95040q104	372	5,292	SH		SOLE		5,292	0	0
WSFS FINANCIAL CORP	COM	929328102	1,778	36,478	SH		SOLE		36,478	0	0
ZURICH INSURANCE GROUP-ADR	COM	989825104	232	7,600	SH		SOLE		7,600	0	0
BLACKROCK ENHANCED EQT DIV TR	ETFS	09251A104	91	10,000	SH		SOLE		10,000	0	0
DEUTSCHE X-TRACKERS MSCI EUROP	ETFS	233051853	247	8,699	SH		SOLE		8,699	0	0
ISHARES CORE S&P MID CAP ETF	ETFS	464287507	1,044	5,834	SH		SOLE		5,834	0	0
ISHARES CORE S&P SMALL CAP ETF	ETFS	464287804	683	9,199	SH		SOLE		9,199	0	0
ISHARES MSCI EAFE ETF	ETFS	464287465	281	4,099	SH		SOLE		4,099	0	0
VANGUARD DIVIDEND APPREC	ETFS	921908844	1,128	11,903	SH		SOLE		11,903	0	0
VANGUARD FTSE ALL WORLD EX US	ETFS	922042775	3,507	66,541	SH		SOLE		66,541	0	0
VANGUARD FTSE EMERGING MARK ET	ETFS	922042858	904	20,738	SH		SOLE		20,738	0	0
VANGUARD HIGH DVD YIELD ETF	ETFS	921946406	826	10,186	SH		SOLE		10,186	0	0
VANGUARD INDEX FDS FORMERLY VA	ETFS	922908363	5,305	22,989	SH		SOLE		22,989	0	0
VANGUARD REIT ETF	ETFS	922908553	749	9,015	SH		SOLE		9,015	0	0
VANGUARD SHORT-TERM GOV BD	ETFS	92206c102	439	7,225	SH		SOLE		7,225	0	0
VANGUARD TOTAL STK MKT ETF	ETFS	922908769	339	2,615	SH		SOLE		2,615	0	0
WISDOMTREE TR INDIA ERNGS FD	ETFS	97717W422	315	12,500	SH		SOLE		12,500	0	0