CONSOLIDATED STATEMENTS OF EQUITY - USD ($) $ in Thousands	Total stockholders' equity	Preferred stock	Common stock	Preferred stock and paid in capital	Common stock and paid in capital	Distributions in excess of net income	Noncontrolling interests	Total
Balance at Dec. 31, 2012	$ 2,412,794			$ 609,363	$ 2,572,092	$ (768,661)		$ 2,412,794
Balance (in shares) at Dec. 31, 2012		25,150,000	133,452,411
Increase (Decrease) in Stockholders' Equity
Net income	245,564					245,564	$ 719	246,283
Distributions paid and payable	(468,697)					(468,697)	(1,371)	(470,068)
Shares issued in stock offerings, net of offering costs	1,133,574				1,133,574			1,133,574
Shares issued in stock offerings, net of offering costs (in shares)			27,025,000
Shares issued in conjunction with acquisition of ARCT, net of our shares owned by ARCT	1,997,850				1,997,850			1,997,850
Shares issued in conjunction with acquisition of ARCT, net of our shares owned by ARCT (in shares)			45,364,435
Issuance of preferred and common units							36,563	36,563
Shares issued pursuant to dividend reinvestment and stock purchase plan, net	55,244				55,244			55,244
Shares issued pursuant to dividend reinvestment and stock purchase plan, net (in shares)			1,449,139
Share-based compensation, net	9,118				9,118			9,118
Share-based compensation, net (in shares)			194,088
Balance at Dec. 31, 2013	5,385,447			609,363	5,767,878	(991,794)	35,911	5,421,358
Balance (in shares) at Dec. 31, 2013		25,150,000	207,485,073
Increase (Decrease) in Stockholders' Equity
Net income	270,635					270,635	1,305	271,940
Distributions paid and payable	(519,790)					(519,790)	(1,839)	(521,629)
Shares issued in stock offerings, net of offering costs	528,592				528,592			528,592
Shares issued in stock offerings, net of offering costs (in shares)			13,800,000
Redemption of common units	1,032				1,032		(1,032)
Redemption of common units (in shares)			35,000
Reallocation of equity	6,647				6,647		(6,647)
Shares issued pursuant to dividend reinvestment and stock purchase plan, net	157,285				157,285			157,285
Shares issued pursuant to dividend reinvestment and stock purchase plan, net (in shares)			3,527,166
Preferred shares redeemed	(220,000)			(213,985)		(6,015)		(220,000)
Preferred shares redeemed (in shares)		(8,800,000)
Share-based compensation, net	3,553				3,553			3,553
Share-based compensation, net (in shares)			33,953
Balance at Dec. 31, 2014	5,613,401			395,378	6,464,987	(1,246,964)	27,698	5,641,099
Balance (in shares) at Dec. 31, 2014		16,350,000	224,881,192
Increase (Decrease) in Stockholders' Equity
Net income	283,766					283,766	1,089	284,855
Distributions paid and payable	(567,012)					(567,012)	(1,652)	(568,664)
Shares issued in stock offerings, net of offering costs	793,559				793,559			793,559
Shares issued in stock offerings, net of offering costs (in shares)			17,000,000
Redemption of common units	4,347				4,347		(4,347)
Redemption of common units (in shares)			168,182
Reallocation of equity	1,051				1,051		(1,051)
Shares issued pursuant to dividend reinvestment and stock purchase plan, net	360,700				360,700			360,700
Shares issued pursuant to dividend reinvestment and stock purchase plan, net (in shares)			7,608,354
Shares issued pursuant to at-the-market program, net	37,747				37,747			37,747
Shares issued pursuant to at-the-market program, net (in shares)			714,301
Share-based compensation, net	6,037				6,037			6,037
Share-based compensation, net (in shares)			44,728
Balance at Dec. 31, 2015	$ 6,531,596			$ 395,378	$ 7,666,428	$ (1,530,210)	$ 21,737	$ 6,553,333
Balance (in shares) at Dec. 31, 2015		16,350,000	250,416,757