Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Assets:
Pledged MBS	$ 3,150,610	$ 3,361,635
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	4,571,937	4,550,000
Preferred stock, shares outstanding	4,571,937	4,550,000
Preferred Stock, aggregate liquidation preference	$ 114,298	$ 113,750
Common stock, par value	$ 0.01	$ 0.01
Common Stock, Shares Authorized	200,000,000	200,000,000
Common Stock, Shares, Issued	49,153,463	49,047,335
Common stock, shares outstanding	49,153,463	49,047,335