Condensed Consolidated Statements of Equity - USD ($) $ in Thousands	Total	Total Stockholders' Equity [Member]	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Cumulative Distributions in Excess of Net Income [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Noncontrolling Interests [Member]	Common Stock [Member]	Common Stock [Member] Total Stockholders' Equity [Member]	Common Stock [Member] Common Stock [Member]	Common Stock [Member] Additional Paid-in Capital [Member]
Beginning balance (in shares) at Dec. 31, 2015			5,750,000	65,182,335
Beginning balance at Dec. 31, 2015	$ 1,053,876	$ 1,053,770	$ 58	$ 652	$ 1,202,541	$ (142,148)	$ (7,333)	$ 106
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	47,035	47,101				47,101		(66)
Other comprehensive income (loss)	(2,049)	(2,049)					(2,049)
Amortization of stock-based compensation	6,775	6,775			6,775
Common stock issuance, net (in shares)											108,731
Common stock issuance, net									$ (1,103)	$ (1,103)	$ 1	$ (1,104)
Repurchase of common stock (in shares)				(31,230)
Repurchase of common stock	(725)	(725)			(725)
Preferred dividends	(7,682)	(7,682)				(7,682)
Common dividends	(82,240)	(82,240)				(82,240)
Ending balance (in shares) at Sep. 30, 2016			5,750,000	65,259,836
Ending balance at Sep. 30, 2016	1,013,887	1,013,847	$ 58	$ 653	1,207,487	(184,969)	(9,382)	40
Beginning balance (in shares) at Dec. 31, 2016			5,750,000	65,285,614
Beginning balance at Dec. 31, 2016	1,015,609	1,015,574	$ 58	$ 653	1,208,862	(192,201)	(1,798)	35
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	54,396	54,438				54,438		(42)
Other comprehensive income (loss)	6,034	6,034					6,034
Change in noncontrolling interests	2,733							2,733
Amortization of stock-based compensation	8,768	8,768			8,768
Common stock issuance, net (in shares)											110,546,599
Common stock issuance, net									$ 2,371,985	$ 2,371,985	$ 1,105	$ 2,370,880
Preferred dividends	(7,682)	(7,682)				(7,682)
Common dividends	(80,014)	(80,014)				(80,014)
Ending balance (in shares) at Sep. 30, 2017			5,750,000	175,832,213
Ending balance at Sep. 30, 2017	$ 3,371,829	$ 3,369,103	$ 58	$ 1,758	$ 3,588,510	$ (225,459)	$ 4,236	$ 2,726