Date when the business acquisition agreement was executed, in CCYY-MM-DD format.

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Number of shares of equity interests issued or issuable to acquire entity.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
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Price of a single share of a number of saleable stocks paid or offered to be paid in a business combination.

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No definition available.

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Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

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Face amount or stated value per share of common stock.

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The maximum number of common shares permitted to be issued by an entity's charter and bylaws.

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Total number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury.

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

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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- Definition

Face (par) amount of debt instrument at time of issuance.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Contractual interest rate for funds borrowed, under the debt agreement.

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- Definition

Date the plan of reorganization is effective, in CCYY-MM-DD format.

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-Name Accounting Standards Codification
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- Definition

The percentage rate used to calculate dividend payments on preferred stock.

+ References

No definition available.

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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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Date the preferred stock has been redeemed, in CCYY-MM-DD format.

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The maximum number of nonredeemable preferred shares (or preferred stock redeemable solely at the option of the issuer) permitted to be issued by an entity's charter and bylaws.

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Total number of nonredeemable preferred shares (or preferred stock redeemable solely at the option of the issuer) issued to shareholders (includes related preferred shares that were issued, repurchased, and remain in the treasury). May be all or portion of the number of preferred shares authorized. Excludes preferred shares that are classified as debt.

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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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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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The number of securities classified as temporary equity that have been sold (or granted) to the entity's shareholders. Securities issued include securities outstanding and securities held in treasury. Temporary equity is a security with redemption features that are outside the control of the issuer, is not classified as an asset or liability in conformity with GAAP, and is not mandatorily redeemable. Includes any type of security that is redeemable at a fixed or determinable price or on a fixed or determinable date or dates, is redeemable at the option of the holder, or has conditions for redemption which are not solely within the control of the issuer. If convertible, the issuer does not control the actions or events necessary to issue the maximum number of shares that could be required to be delivered under the conversion option if the holder exercises the option to convert the stock to another class of equity. If the security is a warrant or a rights issue, the warrant or rights issue is considered to be temporary equity if the issuer cannot demonstrate that it would be able to deliver upon the exercise of the option by the holder in all cases. Includes stock with put option held by ESOP and stock redeemable by holder only in the event of a change in control of the issuer.

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The number of securities classified as temporary equity that have been issued and are held by the entity's shareholders. Securities outstanding equals securities issued minus securities held in treasury. Temporary equity is a security with redemption features that are outside the control of the issuer, is not classified as an asset or liability in conformity with GAAP, and is not mandatorily redeemable. Includes any type of security that is redeemable at a fixed or determinable price or on a fixed or determinable date or dates, is redeemable at the option of the holder, or has conditions for redemption which are not solely within the control of the issuer. If convertible, the issuer does not control the actions or events necessary to issue the maximum number of shares that could be required to be delivered under the conversion option if the holder exercises the option to convert the stock to another class of equity. If the security is a warrant or a rights issue, the warrant or rights issue is considered to be temporary equity if the issuer cannot demonstrate that it would be able to deliver upon the exercise of the option by the holder in all cases. Includes stock with put option held by ESOP and stock redeemable by holder only in the event of a change in control of the issuer.

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Amendment effective date.

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No definition available.

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Expected merger closing date.

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No definition available.

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Number of insurers.

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No definition available.

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Reinsurance agreement termination date.

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No definition available.

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The Company and its Subsidiaries - Additional Information (Detail)					6 Months Ended	12 Months Ended
	Jun. 15, 2018	Feb. 12, 2018 USD ($) $ / shares shares	Feb. 02, 2018	Dec. 11, 2017	Jun. 30, 2018 Insurers $ / shares shares	Dec. 31, 2017 $ / shares shares	Jun. 29, 2018 USD ($)	Jun. 14, 2018	Dec. 31, 2016 shares	May 11, 2015 $ / shares shares	Jan. 05, 2015 shares	Jan. 30, 2014 shares	Mar. 19, 2012 $ / shares shares
Related Party Transaction [Line Items]
Plan Effective Date					Mar. 19, 2012
Common stock, par value \| $ / shares					$ 0.00001	$ 0.00001				$ 0.00001			$ 0.00001
Expected merger close date					Jul. 31, 2018
Common stock, shares authorized					3,500,000,000	3,500,000,000				3,500,000,000			500,000,000
Preferred stock, shares authorized					10,000,000					10,000,000			5,000,000
Convertible preferred stock, par value \| $ / shares					$ 0.00001					$ 0.00001			$ 0.00001
Common stock, shares issued		21,197,619			216,664,908	206,714,132
Common stock, shares outstanding					216,664,908	206,714,132
WMMRC [Member]
Related Party Transaction [Line Items]
Number of primary mortgage insurers \| Insurers					7
Reinsurance agreement termination date			Feb. 02, 2018
Redeemable Convertible Series B Preferred Stock [Member]
Related Party Transaction [Line Items]
Preferred stock, redemption date					Oct. 05, 2019
Preferred stock dividend rate	5.00%					3.00%
Preferred stock, shares issued					600,000	600,000					600,000
Preferred stock, shares outstanding					600,000	600,000			600,000
Amendment Effective Date					Jan. 05, 2018
Redeemable Convertible Series B Preferred Stock [Member] \| Amended and Restated Certificate of Incorporation [Member]
Related Party Transaction [Line Items]
Preferred stock, redemption date					Oct. 05, 2019
Preferred stock dividend rate					5.00%
Redeemable Convertible Series B Preferred Stock [Member] \| Certificate of Amendment [Member]
Related Party Transaction [Line Items]
Amendment Effective Date				Jan. 05, 2018
Convertible Series A Preferred Stock [Member]
Related Party Transaction [Line Items]
Convertible preferred stock, par value \| $ / shares					$ 0.00001	$ 0.00001
Convertible preferred stock, shares issued					1,000,000	1,000,000						1,000,000
Convertible preferred stock, shares outstanding					1,000,000	1,000,000
Merger Sub [Member] \| Senior Notes [Member]
Related Party Transaction [Line Items]
Issued aggregate principal amount \| $							$ 1,700,000,000
Senior Notes due 2021 [Member]
Related Party Transaction [Line Items]
Stated interest rate								6.50%
Senior Notes due 2022 [Member]
Related Party Transaction [Line Items]
Stated interest rate								6.50%
Notes due 2023 [Member] \| Merger Sub [Member] \| Senior Notes [Member]
Related Party Transaction [Line Items]
Stated interest rate							8.125%
Issued aggregate principal amount \| $							$ 950,000,000
Notes due 2026 [Member] \| Merger Sub [Member] \| Senior Notes [Member]
Related Party Transaction [Line Items]
Stated interest rate							9.125%
Issued aggregate principal amount \| $							$ 750,000,000
WMIH Common Stock [Member]
Related Party Transaction [Line Items]
Common stock, shares issued		21,197,619
Merger Agreement [Member]
Related Party Transaction [Line Items]
Merger agreement date		Feb. 12, 2018
Share price, without interest \| $ / shares		$ 18.00
Aggregate amount of merger consideration \| $		$ 1,200,000,000
Merger Agreement [Member] \| WMIH Common Stock [Member]
Related Party Transaction [Line Items]
Stock issued, fully paid and nonassessable shares		12.7793
Common stock, par value \| $ / shares		$ 0.00001