Condensed Consolidated Statement of Noncontrolling Interests and Equity - USD ($) $ in Thousands	Total	Redemption of Operating Partnership units for cash	Preferred Operating Partnership	Operating Partnership	Operating Partnership Redemption of Operating Partnership units for stock	Operating Partnership Redemption of Operating Partnership units for cash	Other	Common Stock	Common Stock Redemption of Operating Partnership units for stock	Additional Paid-in Capital	Additional Paid-in Capital Redemption of Operating Partnership units for stock	Additional Paid-in Capital Redemption of Operating Partnership units for cash	Accumulated Other Comprehensive Income	Accumulated Deficit
Balance, beginning of period (in shares) at Dec. 31, 2017								126,007,091
Balance, beginning of period at Dec. 31, 2017	$ 2,723,807		$ 159,636	$ 213,301			$ 119	$ 1,260		$ 2,569,485			$ 33,290	$ (253,284)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon the exercise of options (in shares)								31,525
Issuance of common stock upon the exercise of options	799									799
Restricted stock grants issued (in shares)								31,136
Restricted stock grants canceled (in shares)								(770)
Compensation expense related to stock-based awards	2,726									2,726
Repayment of receivable for preferred operating units pledged as collateral on loan	495		495
Redemption of Operating Partnership units		$ (2,558)				$ (1,126)						$ (1,432)
Noncontrolling interest in consolidated joint venture	120						120
Repurchase of equity portion of 2013 exchangeable senior notes	(21,000)									(21,000)
Net income	95,430		3,390	3,784										88,256
Other comprehensive income (loss)	23,063		144	938									21,981
Distributions to Operating Partnership units held by noncontrolling interests	(7,909)		(3,488)	(4,421)
Dividends paid on common stock	(98,327)													(98,327)
Balance, end of period (in shares) at Mar. 31, 2018								126,068,982
Balance, end of period at Mar. 31, 2018	2,716,646		160,177	212,476			239	$ 1,260		2,550,578			55,271	(263,355)
Balance, beginning of period (in shares) at Dec. 31, 2017								126,007,091
Balance, beginning of period at Dec. 31, 2017	2,723,807		159,636	213,301			119	$ 1,260		2,569,485			33,290	(253,284)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	198,143
Balance, end of period (in shares) at Jun. 30, 2018								126,146,055
Balance, end of period at Jun. 30, 2018	2,715,802		160,104	213,509			239	$ 1,261		2,554,447			62,930	(276,688)
Balance, beginning of period (in shares) at Mar. 31, 2018								126,068,982
Balance, beginning of period at Mar. 31, 2018	2,716,646		160,177	212,476			239	$ 1,260		2,550,578			55,271	(263,355)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon the exercise of options (in shares)								23,050
Issuance of common stock upon the exercise of options	371							$ 1		370
Restricted stock grants issued (in shares)								50,334
Restricted stock grants canceled (in shares)								(6,311)
Compensation expense related to stock-based awards	3,116									3,116
Redemption of Operating Partnership units (in shares)									10,000
Redemption of Operating Partnership units					$ (383)						$ 383
Issuance of Operating Partnership units in conjunction with acquisitions	1,877			1,877
Net income	102,713		3,492	4,068										95,153
Other comprehensive income (loss)	8,033		50	324									7,659
Distributions to Operating Partnership units held by noncontrolling interests	(8,468)		(3,615)	(4,853)
Dividends paid on common stock	(108,486)													(108,486)
Balance, end of period (in shares) at Jun. 30, 2018								126,146,055
Balance, end of period at Jun. 30, 2018	$ 2,715,802		160,104	213,509			239	$ 1,261		2,554,447			62,930	(276,688)
Balance, beginning of period (in shares) at Dec. 31, 2018	127,103,750							127,103,750
Balance, beginning of period at Dec. 31, 2018	$ 2,785,422		153,096	218,362			240	$ 1,271		2,640,705			34,650	(262,902)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon the exercise of options (in shares)								169,021
Issuance of common stock upon the exercise of options	1,757							$ 3		1,754
Restricted stock grants issued (in shares)								35,022
Restricted stock grants canceled (in shares)								(1,244)
Compensation expense related to stock-based awards	2,954									2,954
Redemption of Operating Partnership units (in shares)									85,501
Redemption of Operating Partnership units					(3,310)					3,310
Issuance of Operating Partnership units in conjunction with acquisitions	23,447		23,447
Net income	102,160		3,164	4,235			(9)							94,770
Other comprehensive income (loss)	(23,993)		(147)	(1,003)									(22,843)
Distributions to Operating Partnership units held by noncontrolling interests	(8,412)		(3,296)	(5,116)
Dividends paid on common stock	(109,523)													(109,523)
Balance, end of period (in shares) at Mar. 31, 2019								127,392,050
Balance, end of period at Mar. 31, 2019	$ 2,773,812		176,264	213,168			231	$ 1,274		2,648,723			11,807	(277,655)
Balance, beginning of period (in shares) at Dec. 31, 2018	127,103,750							127,103,750
Balance, beginning of period at Dec. 31, 2018	$ 2,785,422		153,096	218,362			240	$ 1,271		2,640,705			34,650	(262,902)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 214,849
Balance, end of period (in shares) at Jun. 30, 2019	128,513,095							128,513,095
Balance, end of period at Jun. 30, 2019	$ 2,828,811		176,108	210,235			259	$ 1,285		2,756,799			(27,476)	(288,399)
Balance, beginning of period (in shares) at Mar. 31, 2019								127,392,050
Balance, beginning of period at Mar. 31, 2019	2,773,812		176,264	213,168			231	$ 1,274		2,648,723			11,807	(277,655)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon the exercise of options (in shares)								17,042
Issuance of common stock upon the exercise of options	468									468
Restricted stock grants issued (in shares)								53,789
Restricted stock grants issued	2							$ 2
Restricted stock grants canceled (in shares)								(4,786)
Issuance of common stock, net of offering costs (in shares)								930,000
Issuance of common stock, net of offering costs	98,796							$ 9		98,787
Compensation expense related to stock-based awards	3,998									3,998
Redemption of Operating Partnership units (in shares)									125,000
Redemption of Operating Partnership units					$ (4,823)					4,823
Issuance of Operating Partnership units in conjunction with acquisitions	4,575		4,575
Noncontrolling interest in consolidated joint venture	50						50
Conversion of Preferred C Units in the Operating Partnership for Common Operating Partnership Units			(4,374)	4,374
Net income	112,689		3,129	4,754			(22)							104,828
Other comprehensive income (loss)	(41,302)		(254)	(1,765)									(39,283)
Distributions to Operating Partnership units held by noncontrolling interests	(8,705)		(3,232)	(5,473)
Dividends paid on common stock	$ (115,572)													(115,572)
Balance, end of period (in shares) at Jun. 30, 2019	128,513,095							128,513,095
Balance, end of period at Jun. 30, 2019	$ 2,828,811		$ 176,108	$ 210,235			$ 259	$ 1,285		$ 2,756,799			$ (27,476)	$ (288,399)