CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Cumulative Effect of Change in Accounting Principle	Common Shares	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Distributions in Excess of Accumulated Earnings	Distributions in Excess of Accumulated Earnings Cumulative Effect of Change in Accounting Principle	Total Common Shareholders? Equity	Total Common Shareholders? Equity Cumulative Effect of Change in Accounting Principle	Noncontrolling Interests	Noncontrolling Interests Cumulative Effect of Change in Accounting Principle
Balance at Dec. 31, 2017	$ 2,215,639		$ 84	$ 1,596,514	$ 2,614	$ (32,013)		$ 1,567,199		$ 648,440
Balance (in Shares) at Dec. 31, 2017			83,708,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Conversion of OP Units to Common Shares by limited partners of the Operating Partnership	0			2,068				2,068		(2,068)
Conversion of OP Units to Common Shares by limited partners of the Operating Partnership (in Shares)			117,000
Repurchase of Common Shares	(55,111)		$ (2)	(55,109)				(55,111)
Repurchase of Common Shares (in shares)			(2,294,000)
Dividends/distributions declared ($0.29, $1.13 and $1.09 per Common Share/OP Unit for Year Ended Dec 31, 2020, 2019 and 2018)	(96,010)					(89,122)		(89,122)		(6,888)
Employee and trustee stock compensation, net	12,948			574				574		12,374
Employee and trustee stock compensation, net (in Shares)			26,000
Noncontrolling interest distributions	(24,793)									(24,793)
Noncontrolling interest contributions	47,560									47,560
Comprehensive (loss) income	(18,286)				(2,098)	31,439		29,341		(47,627)
Reallocation of noncontrolling interests	0			4,556				4,556		(4,556)
Balance at Dec. 31, 2018	2,081,947		$ 82	1,548,603	516	(89,696)		1,459,505		622,442
Balance (in Shares) at Dec. 31, 2018			81,557,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Conversion of OP Units to Common Shares by limited partners of the Operating Partnership	$ 0			5,104				5,104		(5,104)
Conversion of OP Units to Common Shares by limited partners of the Operating Partnership (in Shares)			308,000
Repurchase of Common Shares (in shares)	0
Issuance of Common Shares	$ 145,498		$ 5	145,493				145,498
Issuance of Common Shares			5,164,000
Dividends/distributions declared ($0.29, $1.13 and $1.09 per Common Share/OP Unit for Year Ended Dec 31, 2020, 2019 and 2018)	(103,434)					(96,310)		(96,310)		(7,124)
Employee and trustee stock compensation, net	10,957			546				546		10,411
Employee and trustee stock compensation, net (in Shares)			21,000
Noncontrolling interest distributions	(94,289)									(94,289)
Noncontrolling interest contributions	161,628									161,628
Comprehensive (loss) income	(15,342)				(31,691)	53,045		21,354		(36,696)
Reallocation of noncontrolling interests	0			6,611				6,611		(6,611)
Balance at Dec. 31, 2019	$ 2,186,965	$ (400)	$ 87	1,706,357	(31,175)	(132,961)	$ (389)	1,542,308	$ (389)	644,657	$ (11)
Balance (in Shares) at Dec. 31, 2019	87,050,465		87,050,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Acquisition of noncontrolling interest	$ 588			(15,330)				(15,330)		15,918
Conversion of OP Units to Common Shares by limited partners of the Operating Partnership	0			6,544				6,544		(6,544)
Conversion of OP Units to Common Shares by limited partners of the Operating Partnership (in Shares)			408,000
Repurchase of Common Shares	(22,386)		$ (1)	(22,385)				(22,386)
Repurchase of Common Shares (in shares)			(1,219,000)
Dividends/distributions declared ($0.29, $1.13 and $1.09 per Common Share/OP Unit for Year Ended Dec 31, 2020, 2019 and 2018)	(27,155)					(24,937)		(24,937)		(2,218)
Employee and trustee stock compensation, net	10,912			782				782		10,130
Employee and trustee stock compensation, net (in Shares)			30,000
Noncontrolling interest distributions	(27,574)									(27,574)
Noncontrolling interest contributions	52,674									52,674
Comprehensive (loss) income	(125,071)				(43,716)	(8,759)		(52,475)		(72,596)
Reallocation of noncontrolling interests	0			7,197				7,197		(7,197)
Balance at Dec. 31, 2020	$ 2,048,553		$ 86	$ 1,683,165	$ (74,891)	$ (167,046)		$ 1,441,314		$ 607,239
Balance (in Shares) at Dec. 31, 2020	86,268,303		86,269,000