Condensed Consolidated Statements of Shareholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Cumulative effect of accounting change	Common Shares of Beneficial Interest	Paid-in Capital	Accumulated Deficit and Distributions in Excess of Net Earnings	Accumulated Deficit and Distributions in Excess of Net Earnings Cumulative effect of accounting change	Accumulated Other Comprehensive Loss	Noncontrolling Interests in Operating Partnership and Consolidated Joint Venture
Beginning balance (in shares) at Dec. 31, 2019			191,799,909
Beginning balance at Dec. 31, 2019	$ 1,833,018	$ (500)	$ 1,918	$ 2,582,087	$ (736,861)	$ (500)	$ (14,126)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	23,511				23,511
Other comprehensive loss	(29,172)						(29,172)
Distributions on common shares, restricted stock and OP units	(42,568)				(42,568)
Share-based compensation expense	4,298			4,298
Common share issuance related to share-based payment plans, net of shares withheld for employee taxes (in shares)			216,056
Common share issuance related to share-based payment plans, net of shares withheld for employee taxes	(1,506)		$ 2	(1,508)
Issuance of common shares (in shares)			8,250,000
Issuance of common shares	233,595		$ 83	233,512
Ending balance (in shares) at Mar. 31, 2020			200,265,965
Ending balance at Mar. 31, 2020	2,020,676		$ 2,003	2,818,389	(756,418)		(43,298)
Beginning balance (in shares) at Dec. 31, 2019			191,799,909
Beginning balance at Dec. 31, 2019	1,833,018	$ (500)	$ 1,918	2,582,087	(736,861)	$ (500)	(14,126)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	68,547
Ending balance (in shares) at Sep. 30, 2020			203,679,575
Ending balance at Sep. 30, 2020	2,108,872		$ 2,037	2,936,762	(797,935)		(31,992)
Beginning balance (in shares) at Mar. 31, 2020			200,265,965
Beginning balance at Mar. 31, 2020	2,020,676		$ 2,003	2,818,389	(756,418)		(43,298)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	32,662				32,662
Other comprehensive loss	7,255						7,255
Distributions on common shares, restricted stock and OP units	(43,271)				(43,271)
Share-based compensation expense	4,449			4,449
Common share issuance related to share-based payment plans, net of shares withheld for employee taxes (in shares)			255,311
Common share issuance related to share-based payment plans, net of shares withheld for employee taxes	2,202		$ 2	2,200
Issuance of common shares (in shares)			3,094,431
Issuance of common shares	107,033		$ 31	107,002
Ending balance (in shares) at Jun. 30, 2020			203,615,707
Ending balance at Jun. 30, 2020	2,131,006		$ 2,036	2,932,040	(767,027)		(36,043)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	12,374				12,374
Other comprehensive loss	4,051						4,051
Distributions on common shares, restricted stock and OP units	(43,282)				(43,282)
Share-based compensation expense	4,555			4,555
Common share issuance related to share-based payment plans, net of shares withheld for employee taxes (in shares)			63,868
Common share issuance related to share-based payment plans, net of shares withheld for employee taxes	168		$ 1	167
Ending balance (in shares) at Sep. 30, 2020			203,679,575
Ending balance at Sep. 30, 2020	2,108,872		$ 2,037	2,936,762	(797,935)		(31,992)
Beginning balance (in shares) at Dec. 31, 2020			251,702,603
Beginning balance at Dec. 31, 2020	3,792,821		$ 2,517	4,687,823	(895,521)		(4,379)	$ 2,381
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(14,236)				(14,414)			178
Other comprehensive loss	(9,292)						(9,280)	(12)
Distributions on common shares, restricted stock and OP units	(56,029)				(55,909)			(120)
Share-based compensation expense	5,024			4,075				949
Common share issuance related to share-based payment plans, net of shares withheld for employee taxes (in shares)			816,915
Common share issuance related to share-based payment plans, net of shares withheld for employee taxes	(10,081)		$ 8	(10,089)
Ending balance (in shares) at Mar. 31, 2021			252,519,518
Ending balance at Mar. 31, 2021	3,708,207		$ 2,525	4,681,809	(965,844)		(13,659)	3,376
Beginning balance (in shares) at Dec. 31, 2020			251,702,603
Beginning balance at Dec. 31, 2020	3,792,821		$ 2,517	4,687,823	(895,521)		(4,379)	2,381
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(22,327)
Ending balance (in shares) at Sep. 30, 2021			266,769,008
Ending balance at Sep. 30, 2021	4,015,183		$ 2,668	5,110,432	(1,090,595)		(13,477)	6,155
Beginning balance (in shares) at Mar. 31, 2021			252,519,518
Beginning balance at Mar. 31, 2021	3,708,207		$ 2,525	4,681,809	(965,844)		(13,659)	3,376
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(13,399)				(13,370)			(29)
Other comprehensive loss	9,051						9,031	20
Distributions on common shares, restricted stock and OP units	(57,897)				(57,773)			(124)
Share-based compensation expense	5,461			3,922				1,539
Common share issuance related to share-based payment plans, net of shares withheld for employee taxes (in shares)			66,431
Common share issuance related to share-based payment plans, net of shares withheld for employee taxes	(107)		$ 1	(108)
Issuance of common shares (in shares)			8,429,104
Issuance of common shares	214,859		$ 84	214,775
Ending balance (in shares) at Jun. 30, 2021			261,015,053
Ending balance at Jun. 30, 2021	3,866,175		$ 2,610	4,900,398	(1,036,987)		(4,628)	4,782
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	5,308				5,294			14
Other comprehensive loss	(8,868)						(8,849)	(19)
Distributions on common shares, restricted stock and OP units	(59,026)				(58,902)			(124)
Share-based compensation expense	4,284			2,782				1,502
Common share issuance related to share-based payment plans, net of shares withheld for employee taxes (in shares)			9,326
Common share issuance related to share-based payment plans, net of shares withheld for employee taxes	(57)			(57)
Common share issuance related to employee stock purchase plan (in shares)			63,260
Common share issuance related to employee stock purchase plan	1,920		$ 1	1,919
Issuance of common shares (in shares)			5,681,369
Issuance of common shares	205,447		$ 57	205,390
Ending balance (in shares) at Sep. 30, 2021			266,769,008
Ending balance at Sep. 30, 2021	$ 4,015,183		$ 2,668	$ 5,110,432	$ (1,090,595)		$ (13,477)	$ 6,155