Fair Value Measurements (Details) (USD $) In Millions	Sep. 30, 2011	Dec. 31, 2010
Derivative Financial Instruments
Cash Flow Hedges	$ 0.3
Fair Value Measurements (Textual) [Abstract]
Long-term Debt	2,369.7	2,339.6
Level 1 [Member] \| Fair Value, Measurements, Recurring [Member]
Fair Value Measurements
Cash Equivalents	0	596.2
Derivative Financial Instruments
Rabbi Trust Assets	53.2	55.3
Long-term debt	0	0
Level 1 [Member] \| Fair Value, Measurements, Recurring [Member] \| Cash Flow Hedging [Member]
Derivative Financial Instruments
Cash Flow Hedges	0	0
Level 1 [Member] \| Fair Value, Measurements, Recurring [Member] \| Other Forward Contracts [Member]
Derivative Financial Instruments
Other Forward Contracts	0	0
Level 2 [Member] \| Fair Value, Measurements, Recurring [Member]
Fair Value Measurements
Cash Equivalents	0	0
Derivative Financial Instruments
Rabbi Trust Assets	0	0
Long-term debt	(2,861.4)	(2,531.8)
Level 2 [Member] \| Fair Value, Measurements, Recurring [Member] \| Cash Flow Hedging [Member]
Derivative Financial Instruments
Cash Flow Hedges	(0.3)	30.6
Level 2 [Member] \| Fair Value, Measurements, Recurring [Member] \| Other Forward Contracts [Member]
Derivative Financial Instruments
Other Forward Contracts	(0.7)	(0.2)
Level 3 [Member] \| Fair Value, Measurements, Recurring [Member]
Fair Value Measurements
Cash Equivalents	0	0
Derivative Financial Instruments
Rabbi Trust Assets	0	0
Long-term debt	0	0
Level 3 [Member] \| Fair Value, Measurements, Recurring [Member] \| Cash Flow Hedging [Member]
Derivative Financial Instruments
Cash Flow Hedges	0	0
Level 3 [Member] \| Fair Value, Measurements, Recurring [Member] \| Other Forward Contracts [Member]
Derivative Financial Instruments
Other Forward Contracts	0	0
Fair Value, Measurements, Recurring [Member]
Fair Value Measurements
Cash Equivalents	0	596.2
Derivative Financial Instruments
Rabbi Trust Assets	53.2	55.3
Long-term debt	(2,861.4)	(2,531.8)
Fair Value, Measurements, Recurring [Member] \| Cash Flow Hedging [Member]
Derivative Financial Instruments
Cash Flow Hedges	(0.3)	30.6
Fair Value, Measurements, Recurring [Member] \| Other Forward Contracts [Member]
Derivative Financial Instruments
Other Forward Contracts	$ (0.7)	$ (0.2)

Fair Value Measurements.

Name:	gr_FairValueMeasurementsTextualAbstract
Namespace Prefix:	gr
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Rabbi Trust Assets.

+ Details

Name:	gr_RabbiTrustAssets
Namespace Prefix:	gr
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

This element represents the portion of the balance sheet assertion valued at fair value by the entity 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. This item includes currency on hand as well as demand deposits with banks or financial institutions. It also includes other kinds of accounts that have the general characteristics of demand deposits in that the Company may deposit additional funds at any time and also effectively may withdraw funds at any time without prior notice or penalty. Cash equivalents, excluding items classified as marketable securities, include short-term, highly liquid investments that are both readily convertible to known amounts of cash, and so near their maturity that they present minimal risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three years ago does not become a cash equivalent when its remaining maturity is three months.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Cash

-URI http://asc.fasb.org/extlink&oid=6506951

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Cash Equivalents

-URI http://asc.fasb.org/extlink&oid=6507016

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 7, 8, 9, 10

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 7

-Footnote 1

-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 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 8

-Footnote 2

-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.

+ Details

Name:	us-gaap_CashAndCashEquivalentsFairValueDisclosure
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair value as of the balance sheet date of the assets less the liabilities of a derivative or group of derivatives.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 15

-URI http://asc.fasb.org/extlink&oid=6947722&loc=d3e13495-108611

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 45

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 45

-Paragraph 6

-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41271-113958

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 10

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6947722&loc=d3e13433-108611

+ Details

Name:	us-gaap_DerivativeFairValueOfDerivativeNet
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Derivative instrument obligations meeting the definition of a liability which the Company is a party to as of the balance sheet date.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 10

-Subparagraph i

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 6

-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 815

-SubTopic 10

-Section 15

-Paragraph 83

-URI http://asc.fasb.org/extlink&oid=6913464&loc=d3e34841-113949

+ Details

Name:	us-gaap_DerivativeFinancialInstrumentsLiabilitiesFairValueDisclosure
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_DerivativeInstrumentDetailAbstract
Namespace Prefix:	us-gaap
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisAbstract
Namespace Prefix:	us-gaap
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.

+ Details

Name:	us-gaap_LongTermDebtFairValue
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Sum of the carrying values as of the balance sheet date of all long-term debt, which is debt initially having maturities due after one year from the balance sheet date or beyond the operating cycle, if longer, but excluding the portions thereof scheduled to be repaid within one year (current maturities) or the normal operating cycle, if longer, and after deducting unamortized discount or premiums, if any.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

Reference 2: 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)

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

+ Details

Name:	us-gaap_LongTermDebtNoncurrent
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant