Real Estate And Accumulated Depreciation

12 Months Ended

Dec. 31, 2017

SEC Schedule III, Real Estate and Accumulated Depreciation Disclosure [Abstract]

Real Estate and Accumulated Depreciation

	Initial Cost to Company						Gross Amounts Carried at Close of Period
Description	Land		Building and Improvements		Cost Capitalized Subsequent  to Acquisition		Land		Building and Improvements		Total (1)		Accumulated Depreciation			Total Costs, Net of Accumulated Depreciation		Encumbrances (2)			Date of Acquisition / Construction
Centers:
10-Federal Shopping Center	$	1,791	$	7,470	$	1,214	$	1,791	$	8,684	$	10,475	$	(7,396	)	$	3,079	$	(5,624	)	03/20/2008
1919 North Loop West	1,334		8,451		12,906		1,337		21,354		22,691		(11,448		)	11,243		—			12/05/2006
580 Market Place	3,892		15,570		3,918		3,889		19,491		23,380		(8,467		)	14,913		(15,246		)	04/02/2001
8000 Sunset Strip Shopping Center	18,320		73,431		6,642		18,320		80,073		98,393		(13,475		)	84,918		—			06/27/2012
Alabama Shepherd Shopping Center	637		2,026		7,870		1,062		9,471		10,533		(5,458		)	5,075		—			04/30/2004
Argyle Village Shopping Center	4,524		18,103		5,416		4,526		23,517		28,043		(10,116		)	17,927		—			11/30/2001
Avent Ferry Shopping Center	1,952		7,814		1,466		1,952		9,280		11,232		(4,225		)	7,007		—			04/04/2002
Baybrook Gateway	10,623		30,307		3,655		10,623		33,962		44,585		(3,342		)	41,243		—			02/04/2015
Bellaire Blvd. Shopping Center	124		37		936		1,011		86		1,097		(38		)	1,059		—			11/13/2008
Best in the West	13,191		77,159		7,817		13,194		84,973		98,167		(29,385		)	68,782		—			04/28/2005
Blalock Market at I-10	—		4,730		1,970		—		6,700		6,700		(5,202		)	1,498		—			12/31/1990
Boca Lyons Plaza	3,676		14,706		5,667		3,651		20,398		24,049		(7,741		)	16,308		—			08/17/2001
Braeswood Square Shopping Center	—		1,421		1,350		—		2,771		2,771		(2,397		)	374		—			05/28/1969
Broadway Marketplace	898		3,637		2,044		906		5,673		6,579		(3,400		)	3,179		—			12/16/1993
Brookwood Marketplace	7,050		15,134		7,428		7,511		22,101		29,612		(6,520		)	23,092		—			08/22/2006
Brownsville Commons	1,333		5,536		328		1,333		5,864		7,197		(1,852		)	5,345		—			05/22/2006
Bull City Market	930		6,651		817		930		7,468		8,398		(2,408		)	5,990		(3,394		)	06/10/2005
Cambrian Park Plaza	48,803		1,089		104		48,851		1,145		49,996		(938		)	49,058		—			02/27/2015
Camelback Village Square	—		8,720		1,244		—		9,964		9,964		(5,925		)	4,039		—			09/30/1994
Camp Creek Marketplace II	6,169		32,036		1,758		4,697		35,266		39,963		(10,404		)	29,559		—			08/22/2006
Capital Square	1,852		7,406		1,482		1,852		8,888		10,740		(4,280		)	6,460		—			04/04/2002
Centerwood Plaza	915		3,659		3,504		914		7,164		8,078		(2,924		)	5,154		—			04/02/2001
Charleston Commons Shopping Center	23,230		36,877		3,180		23,210		40,077		63,287		(12,025		)	51,262		—			12/20/2006
Cherry Creek Retail Center	5,416		14,624		463		5,416		15,087		20,503		(4,321		)	16,182		—			06/16/2011
Chino Hills Marketplace	7,218		28,872		12,786		7,234		41,642		48,876		(21,094		)	27,782		—			08/20/2002
Citadel Building	3,236		6,168		8,893		534		17,763		18,297		(14,553		)	3,744		—			12/30/1975
College Park Shopping Center	2,201		8,845		7,808		2,641		16,213		18,854		(12,536		)	6,318		(11,004		)	11/16/1998

	Initial Cost to Company						Gross Amounts Carried at Close of Period
Description	Land		Building and Improvements		Cost Capitalized Subsequent  to Acquisition		Land		Building and Improvements		Total (1)		Accumulated Depreciation			Total Costs, Net of Accumulated Depreciation		Encumbrances (2)			Date of Acquisition / Construction
Colonial Plaza	$	10,806	$	43,234	$	15,021	$	10,813	$	58,248	$	69,061	$	(29,114	)	$	39,947	$	—		02/21/2001
Countryside Centre	15,523		29,818		10,466		15,559		40,248		55,807		(13,286		)	42,521		—			07/06/2007
Creekside Center	1,732		6,929		2,160		1,730		9,091		10,821		(4,586		)	6,235		(7,386		)	04/02/2001
Crossing At Stonegate	6,400		23,384		223		6,400		23,607		30,007		(1,359		)	28,648		(14,277		)	02/12/2016
Cullen Plaza Shopping Center	106		2,841		497		106		3,338		3,444		(2,755		)	689		—			03/20/2008
Cypress Pointe	3,468		8,700		1,188		3,793		9,563		13,356		(6,373		)	6,983		—			04/04/2002
Dallas Commons Shopping Center	1,582		4,969		160		1,582		5,129		6,711		(1,496		)	5,215		—			09/14/2006
Deerfield Mall	10,522		94,321		2,243		37,128		69,958		107,086		(4,474		)	102,612		—			05/05/2016
Desert Village Shopping Center	3,362		14,969		2,094		3,362		17,063		20,425		(3,518		)	16,907		—			10/28/2010
Eastern Commons	10,282		16		327		1,569		9,056		10,625		(5,370		)	5,255		—			12/31/2002
Edgewater Marketplace	4,821		11,225		685		4,821		11,910		16,731		(2,651		)	14,080		—			11/19/2010
El Camino Promenade	4,431		20,557		4,896		4,429		25,455		29,884		(10,144		)	19,740		—			05/21/2004
Embassy Lakes Shopping Center	2,803		11,268		2,353		2,803		13,621		16,424		(5,075		)	11,349		—			12/18/2002
Entrada de Oro Plaza Shopping Center	6,041		10,511		2,187		6,115		12,624		18,739		(4,392		)	14,347		—			01/22/2007
Epic Village St. Augustine	283		1,171		4,092		320		5,226		5,546		(3,436		)	2,110		—			09/30/2009
Falls Pointe Shopping Center	3,535		14,289		1,094		3,542		15,376		18,918		(5,964		)	12,954		—			12/17/2002
Festival on Jefferson Court	5,041		13,983		4,248		5,022		18,250		23,272		(7,090		)	16,182		—			12/22/2004
Fiesta Trails	8,825		32,790		8,963		12,769		37,809		50,578		(14,756		)	35,822		—			09/30/2003
Fountain Plaza	1,319		5,276		1,742		1,095		7,242		8,337		(4,458		)	3,879		—			03/10/1994
Francisco Center	1,999		7,997		4,960		2,403		12,553		14,956		(9,643		)	5,313		(9,996		)	11/16/1998
Freedom Centre	2,929		15,302		5,970		6,944		17,257		24,201		(6,646		)	17,555		—			06/23/2006
Galleria Shopping Center	10,795		10,339		8,589		10,504		19,219		29,723		(5,559		)	24,164		—			12/11/2006
Galveston Place	2,713		5,522		5,931		3,279		10,887		14,166		(8,733		)	5,433		—			11/30/1983
Gateway Plaza	4,812		19,249		5,361		4,808		24,614		29,422		(10,684		)	18,738		(23,000		)	04/02/2001
Grayson Commons	3,180		9,023		496		3,163		9,536		12,699		(3,195		)	9,504		(4,612		)	11/09/2004
Green Valley Ranch - Auto Zone	440		—		—		440		—		440		—			440		—			02/12/2016
Greenhouse Marketplace	4,607		22,771		4,166		4,750		26,794		31,544		(10,259		)	21,285		—			01/28/2004
Griggs Road Shopping Center	257		2,303		478		257		2,781		3,038		(1,862		)	1,176		—			03/20/2008
Harrisburg Plaza	1,278		3,924		1,083		1,278		5,007		6,285		(4,271		)	2,014		(8,132		)	03/20/2008
HEB - Dairy Ashford & Memorial	1,717		4,234		—		1,717		4,234		5,951		(1,098		)	4,853		—			03/06/2012
Heights Plaza Shopping Center	58		699		2,596		1,055		2,298		3,353		(1,622		)	1,731		—			06/30/1995
High House Crossing	2,576		10,305		553		2,576		10,858		13,434		(4,496		)	8,938		—			04/04/2002

	Initial Cost to Company							Gross Amounts Carried at Close of Period
Description	Land		Building and Improvements		Cost Capitalized Subsequent  to Acquisition			Land		Building and Improvements		Total (1)		Accumulated Depreciation			Total Costs, Net of Accumulated Depreciation		Encumbrances (2)			Date of Acquisition / Construction
Highland Square	$	—	$	—	$	1,887		$	—	$	1,887	$	1,887	$	(610	)	$	1,277	$	—		10/06/1959
Hilltop Village Center	3,196		7,234		53,872			3,960		60,342		64,302		(13,553		)	50,749		—			01/01/2016
Hope Valley Commons	2,439		8,487		485			2,439		8,972		11,411		(1,891		)	9,520		—			08/31/2010
I45/Telephone Rd.	678		11,182		647			678		11,829		12,507		(6,584		)	5,923		(9,201		)	03/20/2008
Independence Plaza I & II	19,351		31,627		2,251			19,351		33,878		53,229		(7,056		)	46,173		(15,190		)	06/11/2013
Jess Ranch Marketplace	8,750		25,560		631			8,750		26,191		34,941		(4,803		)	30,138		—			12/23/2013
Jess Ranch Marketplace Phase III	8,431		21,470		372			8,431		21,842		30,273		(4,035		)	26,238		—			12/23/2013
Lakeside Marketplace	6,064		22,989		3,159			6,150		26,062		32,212		(8,861		)	23,351		—			08/22/2006
Largo Mall	10,817		40,906		7,231			10,810		48,144		58,954		(17,665		)	41,289		—			03/01/2004
Laveen Village Marketplace	1,190		—		5,124			1,006		5,308		6,314		(3,445		)	2,869		—			08/15/2003
League City Plaza	1,918		7,592		1,508			2,317		8,701		11,018		(5,407		)	5,611		(8,308		)	03/20/2008
Leesville Towne Centre	7,183		17,162		1,690			7,223		18,812		26,035		(6,879		)	19,156		—			01/30/2004
Lowry Town Center	1,889		23,165		163			3,777		21,440		25,217		(891		)	24,326		—			09/14/2016
Madera Village Shopping Center	3,788		13,507		1,391			3,816		14,870		18,686		(4,709		)	13,977		—			03/13/2007
Market at Westchase Shopping Center	1,199		5,821		3,652			1,415		9,257		10,672		(6,295		)	4,377		—			02/15/1991
Marketplace at Seminole Towne	16,067		53,743		10,687			22,711		57,786		80,497		(17,080		)	63,417		—			08/21/2006
Markham West Shopping Center	2,694		10,777		5,330			2,696		16,105		18,801		(9,006		)	9,795		—			09/18/1998
Mendenhall Commons	2,655		9,165		1,106			2,677		10,249		12,926		(3,343		)	9,583		—			11/13/2008
Menifee Town Center	1,827		7,307		5,664			1,824		12,974		14,798		(5,395		)	9,403		—			04/02/2001
Millpond Center	3,155		9,706		2,960			3,161		12,660		15,821		(4,599		)	11,222		—			07/28/2005
Monte Vista Village Center	1,485		58		5,904			755		6,692		7,447		(4,291		)	3,156		—			12/31/2004
Mueller Regional Retail Center	10,382		56,303		1,373			10,382		57,676		68,058		(10,874		)	57,184		(33,045		)	10/03/2013
North Creek Plaza	6,915		25,625		4,930			6,954		30,516		37,470		(12,364		)	25,106		—			08/19/2004
North Towne Plaza	960		3,928		8,820			879		12,829		13,708		(8,764		)	4,944		—			02/15/1990
North Towne Plaza	6,646		99		(5,580		)	259		906		1,165		(576		)	589		—			04/01/2010
Northbrook Shopping Center	1,629		4,489		3,764			1,713		8,169		9,882		(6,811		)	3,071		(9,032		)	11/06/1967
Northwoods Shopping Center	1,768		7,071		703			1,772		7,770		9,542		(3,193		)	6,349		—			04/04/2002
Nottingham Commons	19,523		2,398		20,133			19,664		22,390		42,054		(1,759		)	40,295		—			01/01/2017
Oak Forest Shopping Center	760		2,726		6,798			1,705		8,579		10,284		(6,302		)	3,982		(7,509		)	12/30/1976
Oak Grove Market Center	5,758		10,508		1,122			5,861		11,527		17,388		(3,532		)	13,856		—			06/15/2007
Oracle Crossings	4,614		18,274		29,817			10,582		42,123		52,705		(12,479		)	40,226		—			01/22/2007
Oracle Wetmore Shopping Center	24,686		26,878		7,651			13,813		45,402		59,215		(13,613		)	45,602		—			01/22/2007

	Initial Cost to Company							Gross Amounts Carried at Close of Period
Description	Land		Building and Improvements		Cost Capitalized Subsequent  to Acquisition			Land		Building and Improvements		Total (1)		Accumulated Depreciation			Total Costs, Net of Accumulated Depreciation		Encumbrances (2)			Date of Acquisition / Construction
Overton Park Plaza	$	9,266	$	37,789	$	14,080		$	9,264	$	51,871	$	61,135	$	(20,488	)	$	40,647	$	—		10/24/2003
Palmilla Center	1,258		—		13,235			2,882		11,611		14,493		(7,166		)	7,327		—			12/31/2002
Paradise Marketplace	2,153		8,612		(1,805		)	1,197		7,763		8,960		(4,561		)	4,399		—			07/20/1995
Parliament Square II	2		10		1,183			3		1,192		1,195		(960		)	235		—			06/24/2005
Perimeter Village	29,701		42,337		4,483			34,404		42,117		76,521		(13,941		)	62,580		(31,316		)	07/03/2007
Phillips Crossing	—		1		28,454			872		27,583		28,455		(13,948		)	14,507		—			09/30/2009
Phoenix Office Building	1,696		3,255		1,415			1,773		4,593		6,366		(1,920		)	4,446		—			01/31/2007
Pike Center	—		40,537		3,174			—		43,711		43,711		(10,299		)	33,412		—			08/14/2012
Plantation Centre	3,463		14,821		1,965			3,471		16,778		20,249		(6,208		)	14,041		—			08/19/2004
Prospector's Plaza	3,746		14,985		5,742			3,716		20,757		24,473		(8,537		)	15,936		—			04/02/2001
Pueblo Anozira Shopping Center	2,750		11,000		5,308			2,768		16,290		19,058		(10,150		)	8,908		(14,360		)	06/16/1994
Raintree Ranch Center	11,442		595		17,888			10,983		18,942		29,925		(12,030		)	17,895		—			03/31/2008
Rancho San Marcos Village	3,533		14,138		5,454			3,887		19,238		23,125		(7,871		)	15,254		—			02/26/2003
Rancho Towne & Country	1,161		4,647		785			1,166		5,427		6,593		(3,151		)	3,442		—			10/16/1995
Randalls Center/Kings Crossing	3,570		8,147		423			3,585		8,555		12,140		(5,565		)	6,575		—			11/13/2008
Red Mountain Gateway	2,166		89		11,782			3,317		10,720		14,037		(5,152		)	8,885		—			12/31/2003
Regency Centre	5,616		18,516		3,512			3,581		24,063		27,644		(7,529		)	20,115		—			07/28/2006
Reynolds Crossing	4,276		9,186		292			4,276		9,478		13,754		(2,772		)	10,982		—			09/14/2006
Richmond Square	1,993		953		13,472			14,512		1,906		16,418		(1,294		)	15,124		—			12/31/1996
Ridgeway Trace	26,629		544		23,645			16,100		34,718		50,818		(13,891		)	36,927		—			11/09/2006
River Oaks Shopping Center - East	1,354		1,946		338			1,363		2,275		3,638		(1,992		)	1,646		—			12/04/1992
River Oaks Shopping Center - West	3,534		17,741		35,470			4,207		52,538		56,745		(27,137		)	29,608		—			12/04/1992
River Point at Sheridan	28,898		4,042		16,381			10,659		38,662		49,321		(10,918		)	38,403		—			04/01/2010
Roswell Corners	6,136		21,447		3,439			5,835		25,187		31,022		(8,583		)	22,439		(3,749		)	06/24/2004
Roswell Crossing Shopping Center	7,625		18,573		1,229			7,625		19,802		27,427		(4,904		)	22,523		—			07/18/2012
San Marcos Plaza	1,360		5,439		910			1,358		6,351		7,709		(2,671		)	5,038		—			04/02/2001
Scottsdale Horizon	—		3,241		39,224			12,914		29,551		42,465		(4,587		)	37,878		—			01/22/2007
Scottsdale Waterfront	10,281		40,374		320			32,891		18,084		50,975		(1,142		)	49,833		—			08/17/2016
Sea Ranch Centre	11,977		4,219		1,702			11,977		5,921		17,898		(1,394		)	16,504		—			03/06/2013
Shoppes at Bears Path	3,252		5,503		1,615			3,290		7,080		10,370		(2,524		)	7,846		—			03/13/2007
Shoppes at Memorial Villages	1,417		4,786		9,501			3,332		12,372		15,704		(8,756		)	6,948		—			01/11/2012
Shoppes of South Semoran	5,339		9,785		(1,406		)	5,672		8,046		13,718		(2,470		)	11,248		—			08/31/2007

	Initial Cost to Company							Gross Amounts Carried at Close of Period
Description	Land		Building and Improvements		Cost Capitalized Subsequent  to Acquisition			Land		Building and Improvements		Total (1)		Accumulated Depreciation			Total Costs, Net of Accumulated Depreciation		Encumbrances (2)			Date of Acquisition / Construction
Shops at Kirby Drive	$	1,201	$	945	$	276		$	1,202	$	1,220	$	2,422	$	(507	)	$	1,915	$	—		05/27/2008
Shops at Three Corners	6,215		9,303		11,286			10,587		16,217		26,804		(10,806		)	15,998		—			12/31/1989
Silver Creek Plaza	3,231		12,924		4,532			3,228		17,459		20,687		(7,485		)	13,202		(14,312		)	04/02/2001
Six Forks Shopping Center	6,678		26,759		6,471			6,728		33,180		39,908		(14,383		)	25,525		—			04/04/2002
Southampton Center	4,337		17,349		3,162			4,333		20,515		24,848		(9,436		)	15,412		(19,750		)	04/02/2001
Southgate Shopping Center	232		8,389		726			231		9,116		9,347		(5,801		)	3,546		(5,438		)	03/20/2008
Squaw Peak Plaza	816		3,266		3,472			818		6,736		7,554		(3,841		)	3,713		—			12/20/1994
Stella Link Shopping Center	2,830		1,841		122			2,897		1,896		4,793		(1,641		)	3,152		—			07/10/1970
Stonehenge Market	4,740		19,001		2,415			4,740		21,416		26,156		(9,402		)	16,754		—			04/04/2002
Stony Point Plaza	3,489		13,957		11,400			3,453		25,393		28,846		(11,232		)	17,614		(10,832		)	04/02/2001
Sunset 19 Shopping Center	5,519		22,076		13,959			5,926		35,628		41,554		(10,219		)	31,335		—			10/29/2001
Surf City Crossing	3,220		52		5,100			2,655		5,717		8,372		(2,764		)	5,608		—			12/06/2006
Tates Creek Centre	4,802		25,366		1,869			5,766		26,271		32,037		(9,607		)	22,430		—			03/01/2004
The Centre at Post Oak	13,731		115		24,782			17,822		20,806		38,628		(13,460		)	25,168		—			12/31/1996
The Commons at Dexter Lake	4,946		18,948		3,500			4,988		22,406		27,394		(8,674		)	18,720		—			11/13/2008
The Palms at Town & Country	56,833		195,203		429			102,512		149,953		252,465		(8,324		)	244,141		—			07/27/2016
The Shoppes at Parkwood Ranch	4,369		52		10,339			2,420		12,340		14,760		(7,303		)	7,457		—			12/31/2009
The Westside Center	14,952		10,350		105			14,952		10,455		25,407		(665		)	24,742		—			12/22/2015
Thompson Bridge Commons	604		—		625			513		716		1,229		(130		)	1,099		—			04/26/2005
Thousand Oaks Shopping Center	2,973		13,142		1,030			2,973		14,172		17,145		(5,457		)	11,688		(9,560		)	03/20/2008
TJ Maxx Plaza	3,400		19,283		3,900			3,430		23,153		26,583		(8,240		)	18,343		—			03/01/2004
Tomball Marketplace	9,616		262		24,702			6,726		27,854		34,580		(11,666		)	22,914		—			04/12/2006
Trenton Crossing/North McAllen	9,855		29,133		827			9,855		29,960		39,815		(2,134		)	37,681		—			08/31/2015
Tropicana Beltway Center	13,947		42,186		2,094			13,949		44,278		58,227		(15,750		)	42,477		—			11/20/2007
Tropicana Marketplace	2,118		8,477		(1,263		)	1,206		8,126		9,332		(4,252		)	5,080		—			07/24/1995
Valley Shopping Center	4,293		13,736		1,635			8,910		10,754		19,664		(3,467		)	16,197		—			04/07/2006
Valley View Shopping Center	1,006		3,980		2,248			1,006		6,228		7,234		(3,697		)	3,537		—			11/20/1996
Vizcaya Square Shopping Center	3,044		12,226		2,358			3,044		14,584		17,628		(5,555		)	12,073		—			12/18/2002
Wake Forest Crossing II	395		940		2,503			415		3,423		3,838		(48		)	3,790		—			06/04/2014
Waterford Village	5,830		—		12,264			3,775		14,319		18,094		(6,656		)	11,438		—			06/11/2004
Wellington Green Commons & Pad	16,500		32,489		2,460			16,500		34,949		51,449		(2,609		)	48,840		(18,587		)	04/20/2015
West Jordan Town Center	4,306		17,776		(1,989		)	3,269		16,824		20,093		(7,284		)	12,809		—			12/19/2003

	Initial Cost to Company							Gross Amounts Carried at Close of Period
Description	Land		Building and Improvements		Cost Capitalized Subsequent  to Acquisition			Land		Building and Improvements		Total (1)		Accumulated Depreciation			Total Costs, Net of Accumulated Depreciation		Encumbrances (2)			Date of Acquisition / Construction
Westchase Shopping Center	$	3,085	$	7,920	$	13,586		$	3,189	$	21,402	$	24,591	$	(13,221	)	$	11,370	$	—		08/29/1978
Westhill Village Shopping Center	408		3,002		6,720			437		9,693		10,130		(5,621		)	4,509		—			05/01/1958
Westland Fair	27,562		10,506		(7,267		)	12,220		18,581		30,801		(10,027		)	20,774		—			12/29/2000
Westminster Center	11,215		44,871		8,832			11,204		53,714		64,918		(24,301		)	40,617		(47,250		)	04/02/2001
Winter Park Corners	2,159		8,636		2,057			2,189		10,663		12,852		(4,552		)	8,300		—			09/06/2001
	956,026		2,409,874		857,210			1,043,996		3,179,114		4,223,110		(1,131,628		)	3,091,482		(360,110		)
New Development:
West Alex	42,163		2,669		31,181			44,420		31,593		76,013		—			76,013		—			11/01/2016
The Whittaker	5,237		19,395		1,518			5,366		20,784		26,150		(116		)	26,034		—			03/24/2017
	47,400		22,064		32,699			49,786		52,377		102,163		(116		)	102,047		—
Miscellaneous (not to exceed 5% of total)	136,434		10,310		26,842			92,430		81,156		173,586		(34,382		)	139,204		—
Total of Portfolio	$	1,139,860	$	2,442,248	$	916,751		$	1,186,212	$	3,312,647	$	4,498,859	$	(1,166,126	)	$	3,332,733	$	(360,110	)

___________________

(1) The book value of our net fixed asset exceeds the tax basis by approximately $193.4 million at December 31, 2017.

(2) Encumbrances do not include $50.9 million outstanding under fixed-rate mortgage debt associated with tenancy-in-common arrangements and properties held for sale, $4.0 million of non-cash debt related items and $(1.3) million of deferred debt costs.

Depreciation is computed using the straight-line method, generally over estimated useful lives of 18-40 years for buildings and 10-20 years for parking lot surfacing and equipment. Tenant and leasehold improvements are depreciated over the remaining life of the lease or the useful life whichever is shorter.

The changes in total cost of the properties were as follows (in thousands):

	Year Ended December 31,
	2017			2016			2015
Balance at beginning of year	$	4,789,145		$	4,262,959		$	4,076,094
Additions at cost	137,462			654,513			319,789
Retirements or sales	(334,105		)	(126,666		)	(79,608		)
Property held for sale	(78,721		)	(1,563		)	(53,163		)
Impairment loss	(14,922		)	(98		)	(153		)
Balance at end of year	$	4,498,859		$	4,789,145		$	4,262,959

The changes in accumulated depreciation were as follows (in thousands):

	Year Ended December 31,
	2017			2016			2015
Balance at beginning of year	$	1,184,546		$	1,087,642		$	1,028,619
Additions at cost	132,900			131,120			120,426
Retirements or sales	(127,391		)	(33,132		)	(42,603		)
Property held for sale	(23,929		)	(1,084		)	(18,800		)
Balance at end of year	$	1,166,126		$	1,184,546		$	1,087,642