Write Off Of Unamortized Debt Discount

No definition available.

Name:	gcpwi_WriteOffOfUnamortizedDebtDiscount
Namespace Prefix:	gcpwi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

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.

+ References

No definition available.

+ Details

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

+ References

No definition available.

+ Details

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

- Definition

The cash outflow to repay long-term debt that is wholly or partially secured by collateral. Excludes repayments of tax exempt secured debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3291-108585

+ Details

Name:	us-gaap_RepaymentsOfSecuredDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Write-off of amounts previously capitalized as debt issuance cost in an extinguishment of debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.8)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

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Namespace Prefix:
Data Type:	na
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- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_LoansPayableMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_SecuredDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=gcpwi_CreditAgreementMember
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Data Type:	na
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- Details

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Data Type:	na
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- Details

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- Details

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- Details

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Data Type:	na
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- Details

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Debt and Other Financial Instruments - Carrying Amounts and Fair Values of Debt Instruments (Details) - USD ($) $ in Millions		9 Months Ended
	Jul. 31, 2017	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016	Jan. 27, 2016
Debt Instrument [Line Items]
Repayments of secured debt		$ 416.6	$ 30.7
Senior Notes
Debt Instrument [Line Items]
Stated interest rate		9.50%			9.50%
Term Loan
Debt Instrument [Line Items]
Write off of unamortized debt discount	$ 2.1
Write off of deferred debt issuance cost	3.9
Term Loan \| Secured Debt \| Credit Agreement
Debt Instrument [Line Items]
Repayments of secured debt	$ 272.6
Carrying Amount
Debt Instrument [Line Items]
Fair value		$ 544.1		$ 830.9
Carrying Amount \| Senior Notes
Debt Instrument [Line Items]
Fair value		518.4		517.7
Carrying Amount \| Term Loan
Debt Instrument [Line Items]
Fair value		0.0		266.2
Carrying Amount \| Other Borrowings
Debt Instrument [Line Items]
Fair value		25.7		22.0
Carrying Amount \| Other Borrowings \| Revolving Credit
Debt Instrument [Line Items]
Fair value		0.0		25.0
Fair Value \| Level 2 Inputs
Debt Instrument [Line Items]
Fair value		618.3		924.7
Fair Value \| Senior Notes \| Level 2 Inputs
Debt Instrument [Line Items]
Fair value		592.6		603.1
Fair Value \| Term Loan \| Level 2 Inputs
Debt Instrument [Line Items]
Fair value		0.0		274.6
Fair Value \| Other Borrowings \| Level 2 Inputs
Debt Instrument [Line Items]
Fair value		25.7		22.0
Fair Value \| Other Borrowings \| Revolving Credit \| Level 2 Inputs
Debt Instrument [Line Items]
Fair value		$ 0.0		$ 25.0