CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	1 Months Ended		3 Months Ended	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2016	Mar. 31, 2016	Dec. 31, 2015
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	100,000,000	100,000,000	100,000,000	100,000,000
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	500,000,000	500,000,000	500,000,000	500,000,000
Common stock, shares issued (in shares)	216,516,858	216,516,858	216,516,858	207,604,391
Common stock, shares outstanding (in shares)	216,516,858	216,516,858	216,516,858	207,604,391
Series D Cumulative Redeemable Preferred Stock
Preferred stock, Cumulative Redeemable Preferred Stock, dividend rate (as a percent)			8.00%	8.00%
Preferred stock, Cumulative Redeemable Preferred Stock, shares issued (in shares)	4,600,000	4,600,000	4,600,000	4,600,000
Preferred stock, Cumulative Redeemable Preferred Stock, shares outstanding (in shares)	4,600,000	4,600,000	4,600,000	4,600,000
Preferred stock, Cumulative Redeemable Preferred Stock, liquidation preference (in dollars per share)	$ 25.00	$ 25.00	$ 25.00	$ 25.00
Series E Cumulative Redeemable Preferred Stock
Preferred stock, Cumulative Redeemable Preferred Stock, dividend rate (as a percent)	6.95%	6.95%
Preferred stock, Cumulative Redeemable Preferred Stock, shares issued (in shares)	4,600,000	4,600,000	4,600,000	0
Preferred stock, Cumulative Redeemable Preferred Stock, shares outstanding (in shares)	4,600,000	4,600,000	4,600,000	0
Preferred stock, Cumulative Redeemable Preferred Stock, liquidation preference (in dollars per share)	$ 25.00	$ 25.00	$ 25.00