CONSOLIDATED STATEMENTS OF EQUITY - USD ($) shares in Thousands, $ in Thousands	Total Shareholders' Equity	Common Shares	Additional Paid-in Capital	Accumulated Other Comprehensive (Loss) Income	Accumulated Deficit	Noncontrolling Interest in Subsidiaries	Noncontrolling Interests in Operating Partnership	Total
Balance at Dec. 31, 2018	$ 1,709,678	$ 1,871	$ 2,500,751	$ (1,029)	$ (791,915)	$ 6,771		$ 1,716,449
Balance (in shares) at Dec. 31, 2018		187,145
Balance of Noncontrolling Interests in the Operating Partnership at Dec. 31, 2018							$ 55,819
Increase (Decrease) in Stockholders' Equity
Contributions from noncontrolling interests in subsidiaries						4,828		4,828
Distributions paid to noncontrolling interests in subsidiaries						(66)		(66)
Acquisition of noncontrolling interest in subsidiary	(9,728)		(9,728)			(272)		(10,000)
Issuance of common shares	24,580	$ 8	24,572					24,580
Issuance of common shares (in shares)		773
Issuance of restricted shares (in shares)		19
Conversion from units to shares	1,842	$ 1	1,841				(1,842)	1,842
Conversion from units to shares (in shares)		60
Exercise of stock options	1,049	$ 1	1,048					1,049
Exercise of stock options (in shares)		140
Amortization of restricted shares	798		798					798
Share compensation expense	468		468					468
Adjustment for noncontrolling interest in the Operating Partnership	(6,681)				(6,681)		6,681	(6,681)
Net income (loss)	35,498				35,498	(70)		35,428
Net income (loss)							358
Other comprehensive income, net	240			240				240
Other comprehensive income, net							2
Common share distributions	(60,375)				(60,375)		(604)	(60,375)
Balance at Mar. 31, 2019	1,697,369	$ 1,881	2,519,750	(789)	(823,473)	11,191		1,708,560
Balance (in shares) at Mar. 31, 2019		188,137
Balance of Noncontrolling Interests in the Operating Partnership at Mar. 31, 2019							60,414
Balance at Dec. 31, 2018	1,709,678	$ 1,871	2,500,751	(1,029)	(791,915)	6,771		1,716,449
Balance (in shares) at Dec. 31, 2018		187,145
Balance of Noncontrolling Interests in the Operating Partnership at Dec. 31, 2018							55,819
Increase (Decrease) in Stockholders' Equity
Adjustment for noncontrolling interest in the Operating Partnership								(5,900)
Balance at Dec. 31, 2019	1,799,346	$ 1,936	2,674,745	(729)	(876,606)	7,990		1,807,336
Balance (in shares) at Dec. 31, 2019		193,557
Balance of Noncontrolling Interests in the Operating Partnership at Dec. 31, 2019							62,088	62,088
Balance at Mar. 31, 2019	1,697,369	$ 1,881	2,519,750	(789)	(823,473)	11,191		1,708,560
Balance (in shares) at Mar. 31, 2019		188,137
Balance of Noncontrolling Interests in the Operating Partnership at Mar. 31, 2019							60,414
Increase (Decrease) in Stockholders' Equity
Distributions paid to noncontrolling interests in subsidiaries						(8)		(8)
Acquisition of noncontrolling interest in subsidiary	(22,573)		(22,573)			(5,045)		(27,618)
Issuance of common shares	110,521	$ 34	110,487					110,521
Issuance of common shares (in shares)		3,353
Issuance of restricted shares (in shares)		31
Conversion from units to shares	644		644				(644)	644
Conversion from units to shares (in shares)		20
Exercise of stock options	962	$ 1	961					962
Exercise of stock options (in shares)		85
Amortization of restricted shares	1,231		1,231					1,231
Share compensation expense	439		439					439
Adjustment for noncontrolling interest in the Operating Partnership	(2,713)				(2,713)		2,713	(2,713)
Net income (loss)	49,420				49,420	(41)		49,379
Net income (loss)							499
Other comprehensive income, net	20			20				20
Common share distributions	(61,431)				(61,431)		(597)	(61,431)
Balance at Jun. 30, 2019	1,773,889	$ 1,916	2,610,939	(769)	(838,197)	6,097		1,779,986
Balance (in shares) at Jun. 30, 2019		191,626
Balance of Noncontrolling Interests in the Operating Partnership at Jun. 30, 2019							62,385
Increase (Decrease) in Stockholders' Equity
Contributions from noncontrolling interests in subsidiaries						2,548		2,548
Distributions paid to noncontrolling interests in subsidiaries						(68)		(68)
Acquisition of noncontrolling interest in subsidiary	(2,020)		(2,020)			(598)		(2,618)
Issuance of common shares	61,232	$ 18	61,214					61,232
Issuance of common shares (in shares)		1,773
Issuance of restricted shares (in shares)		1
Exercise of stock options	1,655	$ 2	1,653					1,655
Exercise of stock options (in shares)		154
Amortization of restricted shares	1,214		1,214					1,214
Share compensation expense	440		440					440
Adjustment for noncontrolling interest in the Operating Partnership	(2,894)				(2,894)		2,894	(2,894)
Net income (loss)	42,154				42,154	17		42,171
Net income (loss)							426
Other comprehensive income, net	20			20				20
Common share distributions	(62,048)				(62,048)		(597)	(62,048)
Balance at Sep. 30, 2019	1,813,642	$ 1,936	2,673,440	(749)	(860,985)	7,996		1,821,638
Balance (in shares) at Sep. 30, 2019		193,554
Balance of Noncontrolling Interests in the Operating Partnership at Sep. 30, 2019							65,108
Balance at Dec. 31, 2019	1,799,346	$ 1,936	2,674,745	(729)	(876,606)	7,990		1,807,336
Balance (in shares) at Dec. 31, 2019		193,557
Balance of Noncontrolling Interests in the Operating Partnership at Dec. 31, 2019							62,088	62,088
Increase (Decrease) in Stockholders' Equity
Distributions paid to noncontrolling interests in subsidiaries						(59)		(59)
Issuance of common shares	(118)		(118)					(118)
Issuance of restricted shares (in shares)		30
Amortization of restricted shares	710		710					710
Share compensation expense	530		530					530
Adjustment for noncontrolling interest in the Operating Partnership	7,976				7,976		(7,976)	7,976
Net income (loss)	37,896				37,896	38		37,934
Net income (loss)							383
Other comprehensive income, net	20			20				20
Common share distributions	(64,039)				(64,039)		(650)	(64,039)
Balance at Mar. 31, 2020	1,782,321	$ 1,936	2,675,867	(709)	(894,773)	7,969		1,790,290
Balance (in shares) at Mar. 31, 2020		193,587
Balance of Noncontrolling Interests in the Operating Partnership at Mar. 31, 2020							53,845
Balance at Dec. 31, 2019	1,799,346	$ 1,936	2,674,745	(729)	(876,606)	7,990		1,807,336
Balance (in shares) at Dec. 31, 2019		193,557
Balance of Noncontrolling Interests in the Operating Partnership at Dec. 31, 2019							62,088	62,088
Increase (Decrease) in Stockholders' Equity
Adjustment for noncontrolling interest in the Operating Partnership								(2,000)
Balance at Sep. 30, 2020	1,736,462	$ 1,937	2,682,671	(669)	(947,477)	7,944		1,744,406
Balance (in shares) at Sep. 30, 2020		193,748
Balance of Noncontrolling Interests in the Operating Partnership at Sep. 30, 2020							69,573	69,573
Balance at Mar. 31, 2020	1,782,321	$ 1,936	2,675,867	(709)	(894,773)	7,969		1,790,290
Balance (in shares) at Mar. 31, 2020		193,587
Balance of Noncontrolling Interests in the Operating Partnership at Mar. 31, 2020							53,845
Increase (Decrease) in Stockholders' Equity
Distributions paid to noncontrolling interests in subsidiaries						(42)		(42)
Issuance of common shares	(70)		(70)					(70)
Issuance of restricted shares (in shares)		28
Conversion from units to shares	2,824	$ 1	2,823				(2,824)	2,824
Conversion from units to shares (in shares)		100
Exercise of stock options	135		135					135
Exercise of stock options (in shares)		14
Amortization of restricted shares	1,249		1,249					1,249
Share compensation expense	464		464					464
Adjustment for noncontrolling interest in the Operating Partnership	(615)				(615)		615	(615)
Net income (loss)	38,505				38,505	38		38,543
Net income (loss)							389
Other comprehensive income, net	20			20				20
Common share distributions	(64,081)				(64,081)		(618)	(64,081)
Balance at Jun. 30, 2020	1,760,752	$ 1,937	2,680,468	(689)	(920,964)	7,965		1,768,717
Balance (in shares) at Jun. 30, 2020		193,729
Balance of Noncontrolling Interests in the Operating Partnership at Jun. 30, 2020							51,407
Increase (Decrease) in Stockholders' Equity
Distributions paid to noncontrolling interests in subsidiaries						(60)		(60)
Issuance of common shares	(44)		(44)					(44)
Issuance of restricted shares (in shares)		1
Issuance of OP units							9,000
Exercise of stock options	491		491					491
Exercise of stock options (in shares)		18
Amortization of restricted shares	1,277		1,277					1,277
Share compensation expense	479		479					479
Adjustment for noncontrolling interest in the Operating Partnership	(9,312)				(9,312)		9,312	(9,312)
Net income (loss)	46,891				46,891	39		46,930
Net income (loss)							474
Other comprehensive income, net	20			20				20
Common share distributions	(64,092)				(64,092)		(620)	(64,092)
Balance at Sep. 30, 2020	$ 1,736,462	$ 1,937	$ 2,682,671	$ (669)	$ (947,477)	$ 7,944		1,744,406
Balance (in shares) at Sep. 30, 2020		193,748
Balance of Noncontrolling Interests in the Operating Partnership at Sep. 30, 2020							$ 69,573	$ 69,573