CONSOLIDATED BALANCE SHEETS (UNAUDITED) (Parenthetical) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Dec. 31, 2014
Residential mortgage investments	$ 13,590,000	$ 13,480,000
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	250,000us-gaap_CommonStockSharesAuthorized	250,000us-gaap_CommonStockSharesAuthorized
Common stock, shares issued (in shares)	95,812us-gaap_CommonStockSharesIssued	95,848us-gaap_CommonStockSharesIssued
Common stock, shares outstanding (in shares)	95,812us-gaap_CommonStockSharesOutstanding	95,848us-gaap_CommonStockSharesOutstanding
Preferred stock, par value (in dollars per share)	$ 0.10	$ 0.10
Preferred stock, shares authorized (in shares)	100,000us-gaap_PreferredStockSharesAuthorized	100,000us-gaap_PreferredStockSharesAuthorized
Cumulative Redeemable Preferred Stock, Series E [Member]
Preferred stock, dividend rate (in hundredths)	7.50%
Redeemable Preferred Stock [Member] \| Cumulative Redeemable Preferred Stock, Series E [Member]
Preferred stock, dividend rate (in hundredths)	7.50%
Preferred stock, shares issued (in shares)	8,050	7,618
Preferred stock, shares outstanding (in shares)	8,050	7,618
Preferred stock, aggregate liquidation preference	$ 201,247	$ 190,454

Face amount or stated value per share of common stock.

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