v2.3.0.15

Other Operating (Income) Expense, Net (Schedule Of Other Operating (Income) Expense, Net) (Details) (USD $) In Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Other Operating (Income) Expense, Net [Abstract]
Other operating (income) expense	$ (971)	$ (839)	$ (2,727)	$ (4,780)
Impairment of capital work in progress / property, plant and equipment	3,854		5,319
Other operating (income) expense, net	$ 2,883	$ (839)	$ 2,592	$ (4,780)

X

- Definition

Amount of other operating income (expenses), not previously categorized, from items that are associated with the entity's operation.

+ Details

Name:	g_OtherOperatingIncomeExpense
Namespace Prefix:	g
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Definition

Other Operating (Income) Expense, Net [Abstract]

+ Details

Name:	g_OtherOperatingIncomeExpenseNetAbstract
Namespace Prefix:	g
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

The charge against earnings resulting from the write down of long lived assets other than goodwill due to the difference between the carrying value and lower fair value.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 28

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3602-108585



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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 360

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6391110&loc=d3e2921-110230

+ Details

Name:	us-gaap_OtherAssetImpairmentCharges
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

The net amount of other operating income and expenses, the components of which are not separately disclosed on the income statement, from items that are associated with the entity's normal revenue producing operations.

+ Details

Name:	us-gaap_OtherOperatingIncomeExpenseNet
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration