Subsequent Events (Details) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
	Jan. 22, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Subsequent Event [Line Items]
Preferred stock, shares authorized		100,000,000	100,000,000
Net proceeds from issuance of preferred stock		$ 55,569	$ 0	$ 0
Subsequent Event | Series D Preferred Stock
Subsequent Event [Line Items]
Preferred stock, shares authorized	1,000,000
Preferred stock, share price (usd per share)	$ 25.00
Preferred stock, fixed dividend rate	6.50%
Net proceeds from issuance of preferred stock	$ 24,200
Subsequent Event | Series D Preferred Stock | London Interbank Offered Rate (LIBOR)
Subsequent Event [Line Items]
Preferred stock, floating dividend rate	5.09%