Consolidated Statements of Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Distributions in Excess of Earnings [Member]	Total Stockholders' Equity [Member]	Noncontrolling Interests [Member]
Beginning balance (in shares) at Dec. 31, 2017		98,620,333
Beginning balance at Dec. 31, 2017	$ 3,960,316	$ 986	$ 3,822,492	$ (122,685)	$ 3,700,793	$ 259,523
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	40,971			36,246	36,246	4,725
Issuance of share-based compensation awards	1,864		1,864		1,864
Non-cash amortization of share-based compensation	5,094		5,094		5,094
Settlement of restricted stock units for shares of common stock (in shares)		405,067
Settlement of restricted stock units for shares of common stock	0	$ 4	(4)		0
Repurchase of common stock, stock options and restricted stock units (in shares)		(192,195)
Repurchase of common stock, stock options and restricted stock units	(13,642)	$ (2)	(13,640)		(13,642)
Exchange of common units of the Operating Partnership (in shares)		6,503
Exchange of common units of the Operating Partnership	0	$ 0	244		244	(244)
Distributions to noncontrolling interests in consolidated property partnerships	(2,177)				0	(2,177)
Adjustment for noncontrolling interest	0		335		335	(335)
Dividends declared per common share and common unit ($0.455 and $0.425 per share/unit for the three months ended March 31, 2019 and 2018, respectively)	(44,954)			(44,075)	(44,075)	(879)
Ending balance (in shares) at Mar. 31, 2018		98,839,708
Ending balance at Mar. 31, 2018	$ 3,947,472	$ 988	3,816,385	(130,514)	3,686,859	260,613
Beginning balance (in shares) at Dec. 31, 2018	100,746,988	100,746,988
Beginning balance at Dec. 31, 2018	$ 4,201,261	$ 1,007	3,976,953	(48,053)	3,929,907	271,354
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	41,794			36,903	36,903	4,891
Issuance of share-based compensation awards	2,210		2,210		2,210
Non-cash amortization of share-based compensation	8,817		8,817		8,817
Settlement of restricted stock units for shares of common stock (in shares)		393,240
Settlement of restricted stock units for shares of common stock	0	$ 4	(4)		0
Repurchase of common stock, stock options and restricted stock units (in shares)		(175,204)
Repurchase of common stock, stock options and restricted stock units	(12,130)	$ (1)	(12,129)		(12,130)
Exchange of common units of the Operating Partnership (in shares)		2,000
Exchange of common units of the Operating Partnership	0	$ 0	78		78	(78)
Distributions to noncontrolling interests in consolidated property partnerships	(6,309)				0	(6,309)
Adjustment for noncontrolling interest	0		279		279	(279)
Dividends declared per common share and common unit ($0.455 and $0.425 per share/unit for the three months ended March 31, 2019 and 2018, respectively)	$ (49,315)			(48,394)	(48,394)	(921)
Ending balance (in shares) at Mar. 31, 2019	100,967,024	100,967,024
Ending balance at Mar. 31, 2019	$ 4,183,182	$ 1,010	$ 3,976,204	$ (62,690)	$ 3,914,524	$ 268,658