Fresh Start Accounting - Additional Information (Detail) (USD $)	Dec. 31, 2014	Jan. 30, 2014	Dec. 31, 2013	Mar. 19, 2012
Statement Of Financial Position [Abstract]
Maximum percent of the voting shares of the emerging entity immediately prior to the confirmation of reorganization	50.00%	42.50%		50.00%
Company's reorganization value				$ 76,600,000us-gaap_ReorganizationValue
Amount of cash used for Plan-related liabilities	76,600,000
Loss contract fair market value reserve	$ 12,549,000wmih_LossContractFairMarketValueReserve		$ 46,319,000wmih_LossContractFairMarketValueReserve	$ 63,100,000wmih_LossContractFairMarketValueReserve

Amount attributed to the reconstituted entity, as well as the expected net realizable value of those assets that will be disposed before reconstitution occurs.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Reorganization Value

-URI http://asc.fasb.org/extlink&oid=29635974

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 852

-SubTopic 10

-Section 55

-Paragraph 10

-URI http://asc.fasb.org/extlink&oid=34712771&loc=d3e56426-112766

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 852

-SubTopic 10

-Section 05

-Paragraph 15

-URI http://asc.fasb.org/extlink&oid=6458260&loc=d3e54813-112758

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 852

-SubTopic 10

-Section 55

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=34712771&loc=d3e56239-112766

Name:	us-gaap_ReorganizationValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant