Debt (Senior Notes) (Details) - USD ($)	Oct. 27, 2015	Jan. 01, 2016
Debt Instrument [Line Items]
Weighted average interest rate		5.69%
Senior Notes [Member] \| 9.125% Senior Notes due 2023 [Member]
Debt Instrument [Line Items]
Principle amount	$ 360,000,000
Debt Instrument, Interest Rate, Stated Percentage	9.125%
Debt maturity date	Nov. 01, 2023
Debt fair value		$ 354,600,000
Senior Notes [Member] \| 9.125% Senior Notes due 2023 [Member] \| Debt Instrument, Redemption, Period One [Member]
Debt Instrument [Line Items]
Debt redemption price prior to make-whole premium	100.00%
Debt redemption percentage of principle amount redeemed if using proceeds from certain equity offerings	40.00%
Debt redemption price if using proceeds from certain equity offerings	109.125%

Debt Instrument, Redemption Price, Percentage Excluding Make Whole Premium

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- Definition

Debt Instrument, Redemption Price, Percentage, Using Proceeds From Equity Offerings

+ References

No definition available.

+ Details

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- Definition

Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed, Using Proceeds From Equity Offerings

+ References

No definition available.

+ Details

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Namespace Prefix:	gb_
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- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=34725769&loc=d3e28878-108400

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399

+ Details

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Balance Type:	credit
Period Type:	instant

- 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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- 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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- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

+ 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)(2))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Period Type:	duration

- Definition

Weighted average interest rate of debt outstanding.

+ References

No definition available.

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- 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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Balance Type:	credit
Period Type:	instant

- Details

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- Details

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