Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Balance Sheets
Fair value of mortgage-backed securities pledged as collateral (in dollars)	$ 4,122,610	$ 4,362,532
Fair value of residential whole-loans pledged as collateral	$ 17,860wmc_PledgedResidentialWholeLoans	$ 7,220wmc_PledgedResidentialWholeLoans
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	500,000,000us-gaap_CommonStockSharesAuthorized	500,000,000us-gaap_CommonStockSharesAuthorized
Common stock, shares issued	41,919,801us-gaap_CommonStockSharesIssued	41,719,801us-gaap_CommonStockSharesIssued
Common stock, shares outstanding	41,919,801us-gaap_CommonStockSharesOutstanding	41,719,801us-gaap_CommonStockSharesOutstanding
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized	100,000,000us-gaap_PreferredStockSharesAuthorized	100,000,000us-gaap_PreferredStockSharesAuthorized
Preferred stock, shares outstanding	0us-gaap_PreferredStockSharesOutstanding	0us-gaap_PreferredStockSharesOutstanding

Face amount or stated value per share of common stock.

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Number of shares of common stock outstanding. Common stock represent the ownership interest in a corporation.

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The fair value, as of the date of each statement of financial position presented, of mortgage-related securities, classified as available for sale or held for investment, which are owned but transferred to serve as collateral for the payment of the related debt obligation, primarily a secured borrowing or repurchase agreement, and that are reclassified and separately reported in the statement of financial position because the transferee has the right by contract or custom to sell or re-pledge them.

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Face amount or stated value per share of preferred stock nonredeemable or redeemable solely at the option of the issuer.

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Aggregate share number for all nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer) held by stockholders. Does not include preferred shares that have been repurchased.

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The fair value, as of the date of each statement of financial position presented, of Fair value of residential whole-loans held for investments.

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