CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Parenthetical) - $ / shares	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Dividends declared per share of common stock	$ 0.30	$ 0.30	$ 0.60	$ 0.60
7.875% Series A Cumulative Redeemable Preferred Stock
Preferred series dividends declared, per share			0.984	0.984
7.625% Series C Cumulative Redeemable Preferred Stock
Preferred series dividends declared, per share			0.953	0.953
7.50% Series D Cumulative Redeemable Preferred Stock
Preferred series dividends declared, per share			$ 0.938	$ 0.938