Condensed Consolidated Statement of Noncontrolling Interests and Equity - USD ($) $ in Thousands	Total	Series A Preferred Operating Partnership [Member]	Series B Preferred Operating Partnership [Member]	Series C Preferred Operating Partnership [Member]	Series D Preferred Operating Partnership [Member]	Common Operating Partnership [Member]	Other [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Loss [Member]	Accumulated Deficit [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning of period	$ 2,723,807	$ 14,940	$ 41,902	$ 10,730	$ 92,064	$ 213,301	$ 119	$ 1,260	$ 2,569,485	$ 33,290	$ (253,284)
Balance, end of period	$ 2,723,807	14,940	41,902	10,730	92,064	213,301	119	$ 1,260	2,569,485	33,290	(253,284)
Balance, beginning of period (in shares) at Dec. 31, 2017	126,007,091							126,007,091
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon the exercise of options (in shares)								54,575
Issuance of common stock upon the exercise of options	$ 1,170							$ 1	1,169
Restricted stock grants issued (in shares)								81,470
Restricted stock grants issued	0								0
Restricted stock grants canceled (in shares)								(7,081)
Restricted stock grants cancelled	0
Compensation expense related to stock-based awards	5,842								5,842
Repayment of receivable for preferred operating units pledged as collateral on loan	495			495
Issuance of Operating Partnership units in conjunction with acquisitions	1,877					1,877
Redemption of Operating Partnership units for stock	0					(383)			383
Redemption of Operating Partnership units for stock (in shares)								10,000
Redemption of Operating Partnership units for cash	(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 (loss)	198,143	2,359	1,257	1,408	1,858	7,852					183,409
Other comprehensive income	31,096	194				1,262				29,640
Distributions to Operating Partnership units held by noncontrolling interests	(16,377)	(2,580)	(1,257)	(1,408)	(1,858)	(9,274)
Dividends paid on common stock at $1.64 per share	$ (206,813)										(206,813)
Balance, end of period (in shares) at Jun. 30, 2018	126,146,055							126,146,055
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning of period	$ 2,715,802	14,913	41,902	11,225	92,064	213,509	239	$ 1,261	2,554,447	62,930	(276,688)
Balance, end of period	$ 2,715,802	$ 14,913	$ 41,902	$ 11,225	$ 92,064	$ 213,509	$ 239	$ 1,261	$ 2,554,447	$ 62,930	$ (276,688)