Financing Arrangements - Additional Information (Detail) (USD $)	0 Months Ended	12 Months Ended
	Jan. 30, 2014	Dec. 31, 2014	Dec. 31, 2013	Jan. 05, 2015
Debt Instrument [Line Items]
Loans outstanding		$ 0
Subordinate note issuance terms and conditions		Subordinated Notes may be issued by WMIHC, at WMIHC’s option, in one or more tranches over a three year period, subject to certain terms and conditions, including the conditions that (i) all or substantially all of the proceeds from the issuance of the Subordinated Notes are used by WMIHC to fund the acquisition of the assets of, or equity interests of, or a business line, unit or division of, any entity that has been approved by the Board, (ii) no defaults or events of default shall have occurred under the Note Purchase Agreement and (iii) no violation of certain provisions of the Investor Rights Agreement shall have occurred. KKR Management may refuse to purchase Subordinated Notes from WMIHC in the event that a third party (other than KKR or any of its affiliates) (i) has completed a successful proxy contest against WMIHC or (ii) has publicly initiated or threatened to initiate a proxy contest and, in connection therewith, such third party is granted the right to designate more than one nominee to the Board. Upon such refusal, KKR Management will automatically forfeit a percentage of warrants
Maximum percentage of borrowing available on tangible assets	25.00%
Debt instrument maturity description		Each Subordinated Note will mature on the date that is seven years from the date that the initial Subordinated Note is first issued (the “Initial Issue Date”).
Debt instrument maturity period	7 years
Due interest on note		Interest on the Subordinated Notes is due semi-annually
Subordinated note redemption percentage		100.00%
Convertible preferred stock, shares issued		1,000,000	0
Subsequent Event | Series B Preferred Stock [Member]
Debt Instrument [Line Items]
Convertible preferred stock, shares issued				600,000
Subsequent Event | Affiliates of KKR [Member] | Series B Preferred Stock [Member]
Debt Instrument [Line Items]
Convertible preferred stock, shares issued				200,000
Maximum [Member]
Debt Instrument [Line Items]
Principal available	25,000,000
Tranche A and Tranche A-1 Term Loan [Member]
Debt Instrument [Line Items]
Principal available		25,000,000	25,000,000
Loans outstanding		0	0
Tranche B Term Loan [Member]
Debt Instrument [Line Items]
Principal available		100,000,000	100,000,000
Loans outstanding		0	0
7.50% Subordinated Notes [Member]
Debt Instrument [Line Items]
Principal available	150,000,000
Debt instrument, interest rate, stated percentage	7.50%