Schedule III - Real Estate and Accumulated Depreciation

12 Months Ended

Dec. 31, 2020

SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation Disclosure [Abstract]

Schedule III-Real Estate and Accumulated Depreciation

				Initial Cost						Gross Amounts Carried At Close of Period
Property (Type) (1)	Location	Encumbrances (2)		Land		Building and Land Improvements		Costs Capitalized Subsequent to Acquisition		Land		Building and Land Improvements		Total (3)		Accumulated Depreciation (4)		Year Built or Renovated	Date Acquired (5)
100 Light Street (O)	Baltimore, MD	$	46,543	$	26,715	$	58,002	$	21,859	$	26,715	$	79,861	$	106,576	$	(20,981)	1973/2011	8/7/2015
100 Secured Gateway (O)	Huntsville, AL	—		—		70,552		—		—		70,552		70,552		(566)		2020	3/23/2010
1000 Redstone Gateway (O)	Huntsville, AL	9,666		—		20,533		65		—		20,598		20,598		(4,007)		2013	3/23/2010
1100 Redstone Gateway (O)	Huntsville, AL	10,263		—		19,593		66		—		19,659		19,659		(3,418)		2014	3/23/2010
114 National Business Parkway (O)	Annapolis Junction, MD	—		364		3,109		302		364		3,411		3,775		(1,584)		2002	6/30/2000
1200 Redstone Gateway (O)	Huntsville, AL	11,851		—		22,389		60		—		22,449		22,449		(3,945)		2013	3/23/2010
1201 M Street SE (O)	Washington, DC	—		—		49,785		9,621		—		59,406		59,406		(19,011)		2001	9/28/2010
1201 Winterson Road (O)	Linthicum, MD	—		2,130		17,007		901		2,130		17,908		20,038		(5,506)		1985/2017	4/30/1998
1220 12th Street SE (O)	Washington, DC	—		—		42,464		8,795		—		51,259		51,259		(17,812)		2003	9/28/2010
1243 Winterson Road (L)	Linthicum, MD	—		630		—		—		630		—		630		—		(6)	12/19/2001
131 National Business Parkway (O)	Annapolis Junction, MD	—		1,906		7,623		5,075		1,906		12,698		14,604		(7,442)		1990	9/28/1998
132 National Business Parkway (O)	Annapolis Junction, MD	—		2,917		12,259		4,730		2,917		16,989		19,906		(10,566)		2000	5/28/1999
133 National Business Parkway (O)	Annapolis Junction, MD	—		2,517		10,068		6,274		2,517		16,342		18,859		(10,443)		1997	9/28/1998
134 National Business Parkway (O)	Annapolis Junction, MD	—		3,684		7,517		5,007		3,684		12,524		16,208		(7,329)		1999	11/13/1998
1340 Ashton Road (O)	Hanover, MD	—		905		3,620		2,042		905		5,662		6,567		(3,255)		1989	4/28/1999
13450 Sunrise Valley Drive (O)	Herndon, VA	—		1,386		5,576		4,636		1,386		10,212		11,598		(6,156)		1998	7/25/2003
13454 Sunrise Valley Drive (O)	Herndon, VA	—		2,847		11,986		9,184		2,847		21,170		24,017		(12,075)		1998	7/25/2003
135 National Business Parkway (O)	Annapolis Junction, MD	—		2,484		9,750		6,528		2,484		16,278		18,762		(10,164)		1998	12/30/1998
1362 Mellon Road (O)	Hanover, MD	—		950		3,864		1,065		950		4,929		5,879		(854)		2006	2/10/2006
13857 McLearen Road (O)	Herndon, VA	—		3,507		30,177		4,915		3,507		35,092		38,599		(12,784)		2007	7/11/2012
140 National Business Parkway (O)	Annapolis Junction, MD	—		3,407		24,167		1,751		3,407		25,918		29,325		(10,941)		2003	12/31/2003
141 National Business Parkway (O)	Annapolis Junction, MD	—		2,398		9,538		4,832		2,398		14,370		16,768		(9,190)		1990	9/28/1998
14280 Park Meadow Drive (O)	Chantilly, VA	—		3,731		15,953		5,485		3,731		21,438		25,169		(9,512)		1999	9/29/2004
1460 Dorsey Road (L)	Hanover, MD	—		1,577		76		—		1,577		76		1,653		—		(6)	2/28/2006
14840 Conference Center Drive (O)	Chantilly, VA	—		1,572		8,175		5,751		1,572		13,926		15,498		(7,351)		2000	7/25/2003
14850 Conference Center Drive (O)	Chantilly, VA	—		1,615		8,358		3,873		1,615		12,231		13,846		(7,115)		2000	7/25/2003
14900 Conference Center Drive (O)	Chantilly, VA	—		3,436		14,402		8,659		3,436		23,061		26,497		(13,126)		1999	7/25/2003
1501 South Clinton Street (O)	Baltimore, MD	—		27,964		51,990		20,656		27,964		72,646		100,610		(28,175)		2006	10/27/2009
15049 Conference Center Drive (O)	Chantilly, VA	—		4,415		20,365		17,851		4,415		38,216		42,631		(18,061)		1997	8/14/2002
15059 Conference Center Drive (O)	Chantilly, VA	—		5,753		13,615		4,386		5,753		18,001		23,754		(10,079)		2000	8/14/2002
1550 West Nursery Road (O)	Linthicum, MD	—		14,071		16,930		—		14,071		16,930		31,001		(6,310)		2009	10/28/2009
1560 West Nursery Road (O)	Linthicum, MD	—		1,441		113		—		1,441		113		1,554		(19)		2014	10/28/2009
1610 West Nursery Road (O)	Linthicum, MD	—		259		246		—		259		246		505		(23)		2016	4/30/1998
1616 West Nursery Road (O)	Linthicum, MD	—		393		3,323		75		393		3,398		3,791		(268)		2017	4/30/1998
1622 West Nursery Road (O)	Linthicum, MD	—		393		2,542		—		393		2,542		2,935		(244)		2016	4/30/1998
16442 Commerce Drive (O)	Dahlgren, VA	—		613		2,582		980		613		3,562		4,175		(1,860)		2002	12/21/2004

			Initial Cost			Gross Amounts Carried At Close of Period
Property (Type) (1)	Location	Encumbrances (2)	Land	Building and Land Improvements	Costs Capitalized Subsequent to Acquisition	Land	Building and Land Improvements	Total (3)	Accumulated Depreciation (4)	Year Built or Renovated	Date Acquired (5)
16480 Commerce Drive (O)	Dahlgren, VA	—	1,856	7,425	2,602	1,856	10,027	11,883	(4,274)	2000	12/28/2004
16501 Commerce Drive (O)	Dahlgren, VA	—	522	2,090	1,040	522	3,130	3,652	(1,399)	2002	12/21/2004
16539 Commerce Drive (O)	Dahlgren, VA	—	688	2,860	2,326	688	5,186	5,874	(2,879)	1990	12/21/2004
16541 Commerce Drive (O)	Dahlgren, VA	—	773	3,094	2,594	773	5,688	6,461	(2,696)	1996	12/21/2004
16543 Commerce Drive (O)	Dahlgren, VA	—	436	1,742	838	436	2,580	3,016	(1,231)	2002	12/21/2004
1751 Pinnacle Drive (O)	McLean, VA	—	10,486	42,339	33,689	10,486	76,028	86,514	(38,872)	1989/1995	9/23/2004
1753 Pinnacle Drive (O)	McLean, VA	—	8,275	34,353	23,954	8,275	58,307	66,582	(25,248)	1976/2004	9/23/2004
206 Research Boulevard (O)	Aberdeen, MD	—	—	—	—	—	—	—	(1)	2012	9/14/2007
209 Research Boulevard (O)	Aberdeen, MD	—	134	1,711	327	134	2,038	2,172	(599)	2010	9/14/2007
210 Research Boulevard (O)	Aberdeen, MD	—	113	1,402	248	113	1,650	1,763	(493)	2010	9/14/2007
2100 L Street (O)	Washington, DC	82,882	19,024	92,387	—	19,024	92,387	111,411	—	2020 (7)	8/11/2015
2100 Rideout Road (O)	Huntsville, AL	—	—	7,347	2,995	—	10,342	10,342	(1,786)	2016	3/23/2010
22289 Exploration Drive (O)	Lexington Park, MD	—	1,422	5,719	2,061	1,422	7,780	9,202	(4,126)	2000	3/24/2004
22299 Exploration Drive (O)	Lexington Park, MD	—	1,362	5,791	2,994	1,362	8,785	10,147	(4,888)	1998	3/24/2004
22300 Exploration Drive (O)	Lexington Park, MD	—	1,094	5,038	2,770	1,094	7,808	8,902	(3,624)	1997	11/9/2004
22309 Exploration Drive (O)	Lexington Park, MD	—	2,243	10,419	8,205	2,243	18,624	20,867	(8,227)	1984/1997	3/24/2004
23535 Cottonwood Parkway (O)	California, MD	—	692	3,051	648	692	3,699	4,391	(2,027)	1984	3/24/2004
250 W Pratt St (O)	Baltimore, MD	—	8,057	34,588	16,213	8,057	50,801	58,858	(15,418)	1985	3/19/2015
2500 Riva Road (O)	Annapolis, MD	—	2,791	12,155	1	2,791	12,156	14,947	(12,146)	2000	3/4/2003
2600 Park Tower Drive (O)	Vienna, VA	—	20,284	34,443	3,883	20,284	38,326	58,610	(7,108)	1999	4/15/2015
2691 Technology Drive (O)	Annapolis Junction, MD	—	2,098	17,334	5,565	2,098	22,899	24,997	(11,747)	2005	5/26/2000
2701 Technology Drive (O)	Annapolis Junction, MD	—	1,737	15,266	5,629	1,737	20,895	22,632	(12,487)	2001	5/26/2000
2711 Technology Drive (O)	Annapolis Junction, MD	—	2,251	21,611	4,332	2,251	25,943	28,194	(13,586)	2002	11/13/2000
2720 Technology Drive (O)	Annapolis Junction, MD	—	3,863	29,272	2,796	3,863	32,068	35,931	(13,249)	2004	1/31/2002
2721 Technology Drive (O)	Annapolis Junction, MD	—	4,611	14,597	3,247	4,611	17,844	22,455	(10,267)	2000	10/21/1999
2730 Hercules Road (O)	Annapolis Junction, MD	—	8,737	31,612	8,726	8,737	40,338	49,075	(22,740)	1990	9/28/1998
30 Light Street (O)	Baltimore, MD	3,915	—	12,101	1,009	—	13,110	13,110	(1,894)	2009	8/7/2015
300 Sentinel Drive (O)	Annapolis Junction, MD	—	1,517	59,165	2,095	1,517	61,260	62,777	(16,564)	2009	11/14/2003
302 Sentinel Drive (O)	Annapolis Junction, MD	—	2,648	29,687	1,094	2,648	30,781	33,429	(10,028)	2007	11/14/2003
304 Sentinel Drive (O)	Annapolis Junction, MD	—	3,411	24,917	1,982	3,411	26,899	30,310	(11,186)	2005	11/14/2003
306 Sentinel Drive (O)	Annapolis Junction, MD	—	3,260	22,592	2,566	3,260	25,158	28,418	(9,147)	2006	11/14/2003
308 Sentinel Drive (O)	Annapolis Junction, MD	—	1,422	26,208	2,354	1,422	28,562	29,984	(7,003)	2010	11/14/2003
310 Sentinel Way (O)	Annapolis Junction, MD	—	2,372	42,584	—	2,372	42,584	44,956	(5,027)	2016	11/14/2003
310 The Bridge Street (O)	Huntsville, AL	—	261	26,531	5,135	261	31,666	31,927	(11,066)	2009	8/9/2011
312 Sentinel Way (O)	Annapolis Junction, MD	—	3,138	27,797	—	3,138	27,797	30,935	(4,389)	2014	11/14/2003
314 Sentinel Way (O)	Annapolis Junction, MD	—	1,254	7,741	—	1,254	7,741	8,995	(1,247)	2008	11/14/2003

			Initial Cost			Gross Amounts Carried At Close of Period
Property (Type) (1)	Location	Encumbrances (2)	Land	Building and Land Improvements	Costs Capitalized Subsequent to Acquisition	Land	Building and Land Improvements	Total (3)	Accumulated Depreciation (4)	Year Built or Renovated	Date Acquired (5)
316 Sentinel Way (O)	Annapolis Junction, MD	—	2,748	38,156	226	2,748	38,382	41,130	(8,426)	2011	11/14/2003
318 Sentinel Way (O)	Annapolis Junction, MD	—	2,185	28,426	560	2,185	28,986	31,171	(10,716)	2005	11/14/2003
320 Sentinel Way (O)	Annapolis Junction, MD	—	2,067	21,623	132	2,067	21,755	23,822	(7,029)	2007	11/14/2003
322 Sentinel Way (O)	Annapolis Junction, MD	—	2,605	22,827	1,900	2,605	24,727	27,332	(8,568)	2006	11/14/2003
324 Sentinel Way (O)	Annapolis Junction, MD	—	1,656	23,018	38	1,656	23,056	24,712	(5,956)	2010	6/29/2006
4000 Market Street (O)	Huntsville, AL	6,052	—	9,207	—	—	9,207	9,207	(394)	2018	3/23/2010
410 National Business Parkway (O)	Annapolis Junction, MD	—	1,831	23,257	2,080	1,831	25,337	27,168	(5,032)	2012	6/29/2006
4100 Market Street (O)	Huntsville, AL	5,269	—	8,020	—	—	8,020	8,020	(304)	2019	3/23/2010
420 National Business Parkway (O)	Annapolis Junction, MD	—	2,370	27,751	148	2,370	27,899	30,269	(4,752)	2013	6/29/2006
430 National Business Parkway (O)	Annapolis Junction, MD	—	1,852	21,563	830	1,852	22,393	24,245	(4,936)	2011	6/29/2006
44408 Pecan Court (O)	California, MD	—	817	1,583	1,706	817	3,289	4,106	(1,679)	1986	3/24/2004
44414 Pecan Court (O)	California, MD	—	405	1,619	1,138	405	2,757	3,162	(1,512)	1986	3/24/2004
44417 Pecan Court (O)	California, MD	—	434	3,822	180	434	4,002	4,436	(2,005)	1989/2015	3/24/2004
44420 Pecan Court (O)	California, MD	—	344	890	291	344	1,181	1,525	(546)	1989	11/9/2004
44425 Pecan Court (O)	California, MD	—	1,309	3,506	2,349	1,309	5,855	7,164	(3,431)	1997	5/5/2004
45310 Abell House Lane (O)	California, MD	—	2,272	13,808	816	2,272	14,624	16,896	(3,455)	2011	8/30/2010
4600 River Road (O)	College Park, MD	—	—	23,294	—	—	23,294	23,294	(19)	2020 (7)	1/29/2008
46579 Expedition Drive (O)	Lexington Park, MD	—	1,406	5,796	2,712	1,406	8,508	9,914	(4,231)	2002	3/24/2004
46591 Expedition Drive (O)	Lexington Park, MD	—	1,200	7,199	3,399	1,200	10,598	11,798	(3,932)	2005	3/24/2004
4851 Stonecroft Boulevard (O)	Chantilly, VA	—	1,878	11,558	299	1,878	11,857	13,735	(4,697)	2004	8/14/2002
540 National Business Parkway (O)	Annapolis Junction, MD	—	2,035	31,249	9	2,035	31,258	33,293	(2,521)	2017	6/29/2006
5520 Research Park Drive (O)	Catonsville, MD	—	—	20,072	1,641	—	21,713	21,713	(6,375)	2009	4/4/2006
5522 Research Park Drive (O)	Catonsville, MD	—	—	4,550	855	—	5,405	5,405	(1,652)	2007	3/8/2006
5801 University Research Court (O)	College Park, MD	11,200	—	17,434	—	—	17,434	17,434	(1,195)	2018	1/29/2008
5825 University Research Court (O)	College Park, MD	20,011	—	22,771	1,780	—	24,551	24,551	(7,170)	2008	1/29/2008
5850 University Research Court (O)	College Park, MD	21,171	—	31,906	405	—	32,311	32,311	(8,885)	2008	1/29/2008
6000 Redstone Gateway (O)	Huntsville, AL	—	—	8,268	—	—	8,268	8,268	(14)	2020 (7)	3/23/2010
610 Guardian Way (O)	Annapolis Junction, MD	—	6,946	14,597	—	6,946	14,597	21,543	—	(7)	6/29/2006
6700 Alexander Bell Drive (O)	Columbia, MD	—	1,755	7,019	8,788	1,755	15,807	17,562	(8,825)	1988	5/14/2001
6708 Alexander Bell Drive (O)	Columbia, MD	—	897	12,644	1,618	897	14,262	15,159	(4,674)	1988/2016	5/14/2001
6711 Columbia Gateway Drive (O)	Columbia, MD	—	2,683	23,239	1,557	2,683	24,796	27,479	(9,200)	2006-2007	9/28/2000
6716 Alexander Bell Drive (O)	Columbia, MD	—	1,242	4,969	4,672	1,242	9,641	10,883	(6,123)	1990	12/31/1998
6721 Columbia Gateway Drive (O)	Columbia, MD	—	1,753	34,090	2,391	1,753	36,481	38,234	(10,096)	2009	9/28/2000
6724 Alexander Bell Drive (O)	Columbia, MD	—	449	5,039	2,507	449	7,546	7,995	(3,592)	2001	5/14/2001
6731 Columbia Gateway Drive (O)	Columbia, MD	—	2,807	19,098	5,605	2,807	24,703	27,510	(13,179)	2002	3/29/2000
6740 Alexander Bell Drive (O)	Columbia, MD	—	1,424	5,696	3,466	1,424	9,162	10,586	(6,236)	1992	12/31/1998

			Initial Cost			Gross Amounts Carried At Close of Period
Property (Type) (1)	Location	Encumbrances (2)	Land	Building and Land Improvements	Costs Capitalized Subsequent to Acquisition	Land	Building and Land Improvements	Total (3)	Accumulated Depreciation (4)	Year Built or Renovated	Date Acquired (5)
6741 Columbia Gateway Drive (O)	Columbia, MD	—	675	1,711	169	675	1,880	2,555	(639)	2008	9/28/2000
6750 Alexander Bell Drive (O)	Columbia, MD	—	1,263	12,461	5,075	1,263	17,536	18,799	(10,635)	2001	12/31/1998
6760 Alexander Bell Drive (O)	Columbia, MD	—	890	3,561	3,920	890	7,481	8,371	(4,859)	1991	12/31/1998
6940 Columbia Gateway Drive (O)	Columbia, MD	—	3,545	9,916	8,739	3,545	18,655	22,200	(10,795)	1999	11/13/1998
6950 Columbia Gateway Drive (O)	Columbia, MD	—	3,596	27,723	3,223	3,596	30,946	34,542	(11,991)	1998/2019	10/22/1998
7000 Columbia Gateway Drive (O)	Columbia, MD	—	3,131	12,103	7,537	3,131	19,640	22,771	(9,679)	1999	5/31/2002
7005 Columbia Gateway Drive (L)	Columbia, MD	—	3,036	747	—	3,036	747	3,783	—	(6)	6/26/2014
7015 Albert Einstein Drive (O)	Columbia, MD	—	2,058	6,093	3,319	2,058	9,412	11,470	(4,585)	1999	12/1/2005
7061 Columbia Gateway Drive (O)	Columbia, MD	—	729	3,094	2,640	729	5,734	6,463	(3,393)	2000	8/30/2001
7063 Columbia Gateway Drive (O)	Columbia, MD	—	902	3,684	3,468	902	7,152	8,054	(4,450)	2000	8/30/2001
7065 Columbia Gateway Drive (O)	Columbia, MD	—	919	3,763	3,097	919	6,860	7,779	(4,565)	2000	8/30/2001
7067 Columbia Gateway Drive (O)	Columbia, MD	—	1,829	11,823	5,404	1,829	17,227	19,056	(8,693)	2001	8/30/2001
7100 Redstone Gateway (O)	Huntsville, AL	—	—	9,101	—	—	9,101	9,101	—	(7)	3/23/2010
7125 Columbia Gateway Drive (O)	Columbia, MD	—	20,487	47,029	23,580	20,487	70,609	91,096	(27,691)	1973/1999	6/29/2006
7130 Columbia Gateway Drive (O)	Columbia, MD	—	1,350	4,359	2,896	1,350	7,255	8,605	(3,848)	1989	9/19/2005
7134 Columbia Gateway Drive (O)	Columbia, MD	—	704	4,700	668	704	5,368	6,072	(1,803)	1990/2016	9/19/2005
7138 Columbia Gateway Drive (O)	Columbia, MD	—	1,104	3,518	2,853	1,104	6,371	7,475	(4,072)	1990	9/19/2005
7142 Columbia Gateway Drive (O)	Columbia, MD	—	1,342	7,148	2,611	1,342	9,759	11,101	(4,052)	1994/2018	9/19/2005
7150 Columbia Gateway Drive (O)	Columbia, MD	—	1,032	3,429	813	1,032	4,242	5,274	(1,789)	1991	9/19/2005
7150 Riverwood Drive (O)	Columbia, MD	—	1,821	4,388	1,850	1,821	6,238	8,059	(3,016)	2000	1/10/2007
7160 Riverwood Drive (O)	Columbia, MD	—	2,732	7,006	4,405	2,732	11,411	14,143	(4,768)	2000	1/10/2007
7170 Riverwood Drive (O)	Columbia, MD	—	1,283	3,096	2,281	1,283	5,377	6,660	(2,576)	2000	1/10/2007
7175 Riverwood Drive (O)	Columbia, MD	—	1,788	7,269	—	1,788	7,269	9,057	(1,298)	1996/2013	7/27/2005
7200 Redstone Gateway (O)	Huntsville, AL	—	—	8,348	81	—	8,429	8,429	(1,393)	2013	3/23/2010
7200 Riverwood Drive (O)	Columbia, MD	—	4,089	22,630	4,634	4,089	27,264	31,353	(12,592)	1986	10/13/1998
7205 Riverwood Drive (O)	Columbia, MD	—	1,367	21,419	—	1,367	21,419	22,786	(3,987)	2013	7/27/2005
7272 Park Circle Drive (O)	Hanover, MD	—	1,479	6,300	4,608	1,479	10,908	12,387	(5,467)	1991/1996	1/10/2007
7318 Parkway Drive (O)	Hanover, MD	—	972	3,888	1,324	972	5,212	6,184	(2,929)	1984	4/16/1999
7400 Redstone Gateway (O)	Huntsville, AL	—	—	9,223	75	—	9,298	9,298	(1,281)	2015	3/23/2010
7467 Ridge Road (O)	Hanover, MD	—	1,565	3,116	5,041	1,565	8,157	9,722	(4,110)	1990	4/28/1999
7500 Advanced Gateway (O)	Huntsville, AL	—	—	19,070	—	—	19,070	19,070	(264)	2020	3/23/2010
7600 Advanced Gateway (O)	Huntsville, AL	—	—	14,126	—	—	14,126	14,126	(135)	2020	3/23/2010
7740 Milestone Parkway (O)	Hanover, MD	16,902	3,825	34,176	1,084	3,825	35,260	39,085	(9,279)	2009	7/2/2007
7770 Backlick Road (O)	Springfield, VA	—	6,387	78,779	1,531	6,387	80,310	86,697	(14,971)	2012	3/10/2010
7880 Milestone Parkway (O)	Hanover, MD	—	4,857	25,916	321	4,857	26,237	31,094	(3,384)	2015	9/17/2013
8000 Rideout Road (O)	Huntsville, AL	—	—	16,138	—	—	16,138	16,138	—	(7)	3/23/2010

			Initial Cost			Gross Amounts Carried At Close of Period
Property (Type) (1)	Location	Encumbrances (2)	Land	Building and Land Improvements	Costs Capitalized Subsequent to Acquisition	Land	Building and Land Improvements	Total (3)	Accumulated Depreciation (4)	Year Built or Renovated	Date Acquired (5)
8600 Advanced Gateway (O)	Huntsville, AL	—	—	25,168	—	—	25,168	25,168	(45)	2020	3/23/2010
8621 Robert Fulton Drive (O)	Columbia, MD	—	2,317	12,642	6,191	2,317	18,833	21,150	(6,700)	2005-2006	6/10/2005
8661 Robert Fulton Drive (O)	Columbia, MD	—	1,510	3,764	3,019	1,510	6,783	8,293	(3,528)	2002	12/30/2003
8671 Robert Fulton Drive (O)	Columbia, MD	—	1,718	4,280	4,294	1,718	8,574	10,292	(4,716)	2002	12/30/2003
870 Elkridge Landing Road (O)	Linthicum, MD	—	2,003	9,442	10,464	2,003	19,906	21,909	(11,574)	1981	8/3/2001
8800 Redstone Gateway (O)	Huntsville, AL	11,679	—	18,446	—	—	18,446	18,446	(511)	2019	3/23/2010
891 Elkridge Landing Road (O)	Linthicum, MD	—	1,165	4,772	3,512	1,165	8,284	9,449	(5,193)	1984	7/2/2001
901 Elkridge Landing Road (O)	Linthicum, MD	—	1,156	4,437	4,789	1,156	9,226	10,382	(4,687)	1984	7/2/2001
911 Elkridge Landing Road (O)	Linthicum, MD	—	1,215	4,861	3,431	1,215	8,292	9,507	(4,786)	1985	4/30/1998
938 Elkridge Landing Road (O)	Linthicum, MD	—	922	4,748	1,516	922	6,264	7,186	(3,221)	1984	7/2/2001
939 Elkridge Landing Road (O)	Linthicum, MD	—	939	3,756	4,444	939	8,200	9,139	(5,388)	1983	4/30/1998
9651 Hornbaker Road (D)	Manassas, VA	—	6,050	250,355	16,105	6,050	266,460	272,510	(72,246)	2010	9/14/2010
Arundel Preserve (L)	Hanover, MD	—	13,352	9,699	—	13,352	9,699	23,051	—	(6)	7/2/2007
Canton Crossing Land (L)	Baltimore, MD	—	17,285	8,363	142	17,285	8,505	25,790	—	(6)	10/27/2009
Canton Crossing Util Distr Ctr (O)	Baltimore, MD	—	6,100	10,450	1,689	6,100	12,139	18,239	(6,269)	2006	10/27/2009
Columbia Gateway - Southridge (L)	Columbia, MD	—	6,387	3,722	—	6,387	3,722	10,109	—	(6)	9/20/2004
Dahlgren Technology Center (L)	Dahlgren, VA	—	978	178	—	978	178	1,156	—	(6)	3/16/2005
Expedition VII (O)	Lexington Park, MD	—	705	862	—	705	862	1,567	—	(7)	3/24/2004
IN 1 (O)	Northern Virginia	—	1,815	15,972	—	1,815	15,972	17,787	(735)	2019	8/31/2016
IN 2 (O)	Northern Virginia	—	2,627	28,829	—	2,627	28,829	31,456	(1,081)	2019	8/31/2016
M Square Research Park (L)	College Park, MD	—	—	2,020	—	—	2,020	2,020	—	(6)	1/29/2008
MP 1 (O)	Northern Virginia	—	9,426	30,924	—	9,426	30,924	40,350	(1,240)	2019	11/20/2017
MP 2 (O)	Northern Virginia	—	9,426	29,989	—	9,426	29,989	39,415	(1,416)	2018	11/20/2017
MR Land (L)	Northern Virginia	—	9,038	514	—	9,038	514	9,552	—	(6)	11/8/2018
National Business Park North (L)	Annapolis Junction, MD	—	21,898	35,639	—	21,898	35,639	57,537	—	(6)	6/29/2006
North Gate Business Park (L)	Aberdeen, MD	—	1,755	5	—	1,755	5	1,760	—	(6)	9/14/2007
NoVA Office A (O) (8)	Chantilly, VA	—	2,096	46,849	10	2,096	46,859	48,955	(6,926)	2015	7/18/2002
NoVA Office B (O) (8)	Chantilly, VA	—	739	38,376	—	739	38,376	39,115	(3,734)	2016	7/18/2002
NoVA Office C (O) (8)	Chantilly, VA	—	5,604	48,235	—	5,604	48,235	53,839	—	(7)	7/18/2002
NoVA Office D (O) (8)	Chantilly, VA	—	6,587	40,559	—	6,587	40,559	47,146	(3,450)	2017	7/2/2013
Oak Grove A (O)	Northern Virginia	—	12,866	34,427	—	12,866	34,427	47,293	(494)	2020	11/1/2018
Oak Grove B (O)	Northern Virginia	—	12,866	40,550	—	12,866	40,550	53,416	(811)	2019	11/1/2018
Oak Grove Phase II (L)	Northern Virginia	—	23,483	8,833	—	23,483	8,833	32,316	—	(6)	11/1/2018
Old Annapolis Road (O)	Columbia, MD	—	1,637	5,500	6,710	1,637	12,210	13,847	(4,870)	1974/1985	12/14/2000
P2 A (O)	Northern Virginia	—	16,878	39,934	—	16,878	39,934	56,812	(738)	2020	5/2/2019
P2 B (O)	Northern Virginia	—	22,866	35,960	—	22,866	35,960	58,826	(292)	2020	5/2/2019

				Initial Cost						Gross Amounts Carried At Close of Period
Property (Type) (1)	Location	Encumbrances (2)		Land		Building and Land Improvements		Costs Capitalized Subsequent to Acquisition		Land		Building and Land Improvements		Total (3)		Accumulated Depreciation (4)		Year Built or Renovated	Date Acquired (5)
P2 C (O)	Northern Virginia	—		14,842		30,272		—		14,842		30,272		45,114		(60)		2020	5/2/2019
Paragon Park (L)	Northern Virginia	—		7,738		462		—		7,738		462		8,200		—		(6)	5/8/2017
Parkstone A (O)	Northern Virginia	—		3,942		1,257		—		3,942		1,257		5,199		—		(7)	1/27/2005
Parkstone B (O)	Northern Virginia	—		3,346		1,074		—		3,346		1,074		4,420		—		(7)	1/27/2005
Patriot Ridge (L)	Springfield, VA	—		18,517		14,562		—		18,517		14,562		33,079		—		(6)	3/10/2010
Project EL (O)	Confidential-USA	—		7,430		7,479		—		7,430		7,479		14,909		—		(7)	1/20/2006
Project EX (O) (9)	Confidential-USA	—		8,959		16,981		—		8,959		16,981		25,940		(698)		2018	7/16/2008
Redstone Gateway (L)	Huntsville, AL	—		—		33,310		—		—		33,310		33,310		(5)		(6)	3/23/2010
Sentry Gateway (L)	San Antonio, TX	—		4,052		1,833		—		4,052		1,833		5,885		—		(6)	3/30/2005
Sentry Gateway - T (O)	San Antonio, TX	—		14,020		38,804		13		14,020		38,817		52,837		(13,473)		1982/2008	3/30/2005
Sentry Gateway - V (O)	San Antonio, TX	—		—		1,066		—		—		1,066		1,066		(321)		2007	3/30/2005
Sentry Gateway - W (O)	San Antonio, TX	—		—		1,884		71		—		1,955		1,955		(548)		2009	3/30/2005
Sentry Gateway - X (O)	San Antonio, TX	—		1,964		21,178		—		1,964		21,178		23,142		(5,375)		2010	1/20/2006
Sentry Gateway - Y (O)	San Antonio, TX	—		1,964		21,298		—		1,964		21,298		23,262		(5,407)		2010	1/20/2006
Sentry Gateway - Z (O)	San Antonio, TX	—		1,964		30,573		—		1,964		30,573		32,537		(4,438)		2015	6/14/2005
SP Manassas (L)	Manassas, VA	—		8,156		187		—		8,156		187		8,343		—		(6)	7/24/2019
Westfields - Park Center (L)	Chantilly, VA	—		10,815		6,206		—		10,815		6,206		17,021		—		(6)	7/2/2013
Other Developments, including intercompany eliminations (V)	Various	—		—		282		257		—		539		539		(90)		Various	Various
		$	257,404	$	712,057	$	3,427,401	$	547,344	$	712,057	$	3,974,745	$	4,686,802	$	(1,124,253)

(1)A legend for the Property Type follows: (O) = Office or Data Center Shell Property; (L) = Land held or pre-development; (D) = Wholesale Data Center; and (V) = Various.

(2)Excludes our Revolving Credit Facility of $143.0 million, term loan facilities of $398.4 million, unsecured senior notes of $1.3 billion, unsecured notes payable of $900,000, and deferred financing costs, net of premiums, on the remaining loans of $2.3 million.

(3)The aggregate cost of these assets for Federal income tax purposes was approximately $3.6 billion as of December 31, 2020.

(4)The estimated lives over which depreciation is recognized follow: Building and land improvements: 10-40 years; and tenant improvements: related lease terms.

(5)The acquisition date of multi-parcel properties reflects the date of the earliest parcel acquisition. The acquisition date of properties owned through real estate joint ventures reflects the date of the formation of the joint venture.

(6)Held as of December 31, 2020.

(7)Under development or redevelopment as of December 31, 2020.

(8)The carrying amounts of these properties exclude allocated costs of the garage being constructed to support the properties.

(9)This property represents land under a long-term contract.

The following table summarizes our changes in cost of properties for the years ended December 31, 2020, 2019 and 2018 (in thousands):

		2020		2019		2018
	Beginning balance	$	4,348,006	$	4,148,529	$	3,980,813
	Improvements and other additions	405,940		480,418		224,524
	Sales (1)	(65,475)		(242,497)		(53,547)
	Impairments	(1,530)		(329)		(2,493)
	Other dispositions	(139)		(340)		(768)
	Reclassification to right-of use asset	—		(37,775)		—
	Ending balance	$	4,686,802	$	4,348,006	$	4,148,529
The following table summarizes our changes in accumulated depreciation for the same time periods (in thousands):
		2020		2019		2018
	Beginning balance	$	1,007,120	$	897,903	$	801,038
	Depreciation expense	119,377		117,973		112,610
	Sales (1)	(2,105)		(8,416)		(14,845)
	Impairments	—		—		(132)
	Other dispositions	(139)		(340)		(768)
	Ending balance	$	1,124,253	$	1,007,120	$	897,903

(1)Includes our sale, through a series of transactions, of ownership interests in data center shells through newly-formed unconsolidated real estate joint ventures in 2020 and 2019, as described in Note 4 to our consolidated financial statements.