Equity and Accumulated Other Comprehensive Loss, Net Equity and Accumulated Other Comprehensive Loss, Net (6.350% Series I Cumulative Redeemable Preferred Stock Narrative) (Details) $ / shares in Units, $ in Thousands			12 Months Ended
	Dec. 31, 2015 quarter $ / shares shares	Aug. 24, 2015 USD ($) $ / shares shares	Dec. 31, 2015 USD ($) quarter $ / shares shares	Dec. 31, 2014 USD ($) $ / shares shares	Dec. 31, 2013 USD ($)
Class of Stock [Line Items]
Gross proceeds from the issuance of preferred stock | $			$ 250,000	$ 365,000	$ 250,000
Series I Preferred Stock and Unit
Class of Stock [Line Items]
Net proceeds from sale of common stock (shares) | shares		10,000,000
Preferred Stock, liquidation preference per share/unit	$ 25	$ 25.00	$ 25	$ 0
Preferred stock dividends per share declared (in dollars per share)	$ 0.56003	$ 1.5875
Preferred stock, shares issued (in shares) | shares	10,000,000		10,000,000	0
Preferred stock, dividend rate		6.35%	6.35%	0.00%
Gross proceeds from the issuance of preferred stock | $		$ 242,000
Annual rate of dividend per share (in dollars per share)			$ 1.588
Preferred stock, redemption price per share (in dollars per share)	$ 25.00		$ 25.00
Number of quarters with no dividends triggering voting rights | quarter	6		6
Shares issued upon conversion | shares	0.76231		0.76231