Consolidated Statements of Stockholders' Equity - 3 months ended Mar. 31, 2017 - USD ($) $ in Thousands	Total	Preferred Stock/Units [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]
Balance at Dec. 31, 2016	$ 967,002	$ 201,250	$ 76	$ 766,732	$ 0	$ (1,056)
Balance, shares at Dec. 31, 2016	75,914,763
Net income attributable to controlling interests	$ 38,563				38,563
Other comprehensive loss attributable to controlling interests - foreign currency translation adjustments	16					16
Dividends declared on common stock	(38,918)			(3,688)	(35,230)
Dividends earned on preferred stock	$ (3,333)				(3,333)
Redemption of operating partnership units, shares	1,773,147
Redemption of operating partnership units	$ 77,894		2	77,892
Issuance of stock awards, shares	233,655
Issuance of stock awards	$ 0		0	0
Retirement and forfeiture of stock awards, shares	(85,395)
Retirement and forfeiture of stock awards	$ (3,975)		0	(3,975)
Amortization of deferred compensation costs	2,609			2,609
Adjustments to redeemable noncontrolling interests – operating partnership	(66,249)			(66,249)
Balance at Mar. 31, 2017	$ 973,609	$ 201,250	$ 78	$ 773,321	$ 0	$ (1,040)
Balance, shares at Mar. 31, 2017	77,836,170