Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Assets:
Pledged MBS	$ 3,070,435	$ 3,150,610
Shareholders' Equity:
Preferred Stock, Par Value Per Share	$ 0.01	$ 0.01
Preferred Stock, Shares Authorized	50,000,000	50,000,000
Preferred Stock, Shares Issued	4,897,138	4,571,937
Preferred Stock, Shares Outstanding	4,897,138	4,571,937
Preferred Stock, aggregate liquidation preference	$ 122,428	$ 114,298
Common stock, par value	$ 0.01	$ 0.01
Common Stock, Shares Authorized	200,000,000	200,000,000
Common Stock, Shares, Issued	49,203,022	49,153,463
Common stock, shares outstanding	49,203,022	49,153,463