Net Income (Loss) Per Common Share - Calculation of Diluted Net Income (Loss) Per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended	12 Months Ended
Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Numerator for basic and diluted net income (loss) per share:
Net income (loss)	$ 5,501us-gaap_NetIncomeLoss	$ (3,380)us-gaap_NetIncomeLoss	$ 3,070us-gaap_NetIncomeLoss
Preferred deemed dividend		(9,455)wmih_PreferredDeemedDividend
Series B preferred stock dividends	(4,248)us-gaap_DividendsPreferredStock
Net income (loss) attributable to common shareholders	$ 1,253	$ (12,835)
Denominator for diluted net income (loss) per share:
Weighted-average shares outstanding	202,343,245	201,978,462
Weighted-average unvested restricted shares outstanding	(1,196,680)	(1,504,392)
Effect of dilutive potential shares	301,292,296
Denominator for diluted net income (loss) per share:	502,438,861	200,474,070
Diluted net income (loss) per share attributable to common shareholders	$ 0.00us-gaap_EarningsPerShareDiluted	$ (0.06)us-gaap_EarningsPerShareDiluted

Amount of paid and unpaid preferred stock dividends declared with the form of settlement in cash, stock and payment-in-kind (PIK).

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