Equity - Redemption of Preferred Stock (Details) - USD ($) $ / shares in Units, $ in Thousands, shares in Millions	1 Months Ended	12 Months Ended
	Sep. 30, 2014	Dec. 31, 2014
Excess of redemption value over carrying value of preferred shares subject to redemption		$ 6,015
Class E Cumulative Redeemable Preferred Stock
Preferred stock redeemed (in shares)	8.8
Preferred stock, dividend rate (as a percent)	6.75%
Preferred stock, redemption price per share (in dollars per share)	$ 25.00
Excess of redemption value over carrying value of preferred shares subject to redemption	$ 6,000