Fresh Start Accounting - Adjustment in Fair Value and Reorganization (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 19, 2012
Adjustment in fair value and reorganization
Predecessor retained earnings	$ 101,677
Adjustment for carve-out allocations	23,109
Predecessor adjusted retained earnings	(124,786)
Predecessor additional paid-in capital	69,879
Predecessor common stock eliminated in consolidation	(1)
Predecessor [Member]
Adjustment in fair value and reorganization
Predecessor retained earnings	101,677
Adjustment for carve-out allocations	23,109
Predecessor adjusted retained earnings	124,786
Predecessor additional paid-in capital	69,879
Predecessor common stock eliminated in consolidation	(1)
Predecessor equity value	194,664
Fair Value Adjustments [Member]
Adjustment in fair value and reorganization
Fair market value of WMMRC	131,600
Loss contract fair market reserve allowance	$ 63,064

Amount of fresh-start adjustment to retained earnings or deficit.

Reference 1: 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=6585303&loc=d3e56426-112766

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

-Publisher AICPA

-Name Statement of Position (SOP)

-Number 90-7

-Paragraph 39, 68

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 852

-SubTopic 10

-Section 45

-Paragraph 21

-URI http://asc.fasb.org/extlink&oid=6916575&loc=d3e55811-112764

+ Details

Name:	us-gaap_FreshStartAdjustmentIncreaseDecreaseRetainedEarningsDeficit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of additional paid-in capital at the balance sheet date before fresh-start adjustments.

+ References

+ Details

Name:	us-gaap_PreconfirmationAdditionalPaidInCapital
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of retained earnings or deficit at the balance sheet date before fresh-start adjustments.

+ References

+ Details

Name:	us-gaap_PreconfirmationRetainedEarningsDeficit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	wmih_AdjustmentInFairValueAndReorganizationAbstract
Namespace Prefix:	wmih_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Loss contract fair market reserve allowance.

+ References

No definition available.

+ Details

Name:	wmih_LossContractFairMarketReserveAllowance
Namespace Prefix:	wmih_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Preconfirmation fair value adjustment common stock.

+ References

No definition available.

+ Details

Name:	wmih_PreconfirmationFairValueAdjustmentCommonStock
Namespace Prefix:	wmih_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Preconfirmation fair value adjustment retained earnings deficit.

+ References

No definition available.

+ Details

Name:	wmih_PreconfirmationFairValueAdjustmentRetainedEarningsDeficit
Namespace Prefix:	wmih_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Preconfirmation stockholders equity after carve out allocation.

+ References

No definition available.

+ Details

Name:	wmih_PreconfirmationStockholdersEquityAfterCarveOutAllocation
Namespace Prefix:	wmih_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Preconfirmation stockholders equity after carve out allocation at fair value.

+ References

No definition available.

+ Details

Name:	wmih_PreconfirmationStockholdersEquityAfterCarveOutAllocationAtFairValue
Namespace Prefix:	wmih_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant