Long-Term Debt - Narrative (Detail) - USD ($)	6 Months Ended	12 Months Ended
Long-Term Debt - Narrative (Detail) - USD ($)	Jun. 30, 2025	Dec. 31, 2024	Jun. 30, 2024	Mar. 31, 2021
Debt Instrument [Line Items]
Margin over LIBOR (in percentage)	1.375%
Net debt to EBITDA leverage ratio, covenant line of credit	300.00%
Interest coverage minimum ratio, covenant line of credit	3
Long-term debt, amount	$ 1,209,087,000	$ 1,221,440,000
Term loan
Debt Instrument [Line Items]
Debt amortization expense	747,000	911,000
Long-term debt, amount	463,002,000	476,089,000
Principal amount of term loan	$ 6,625,000
2022 facility \| Maximum
Debt Instrument [Line Items]
Term SOFR adjustment (in percentage)	0.10%
2022 facility \| Minimum
Debt Instrument [Line Items]
Term SOFR adjustment (in percentage)	0.00%
2022 facility \| Line of credit
Debt Instrument [Line Items]
Debt instrument, face amount	$ 650,000,000
2022 facility \| Term loan
Debt Instrument [Line Items]
Debt instrument, face amount	$ 530,000,000
Amended 2015 facility
Debt Instrument [Line Items]
Margin over LIBOR (in percentage)	0.20%
Credit facility, base rate (in percentage)	0.375%
2021 Senior notes
Debt Instrument [Line Items]
Long-term debt, amount	$ 349,532,000	349,234,000
2021 Senior notes \| Genpact Luxembourg S.r.l.
Debt Instrument [Line Items]
Debt instrument, face amount				$ 350,000,000
Debt amortization expense	468,000	766,000
Long-term debt, amount	$ 349,532,000	349,234,000
Interest rate on senior notes (in percentage)	1.75%			1.75%
Total debt issuance cost				$ 3,032,000
Debt instrument redemption price (in percentage)	100.00%
Debt repurchase price as percentage of aggregate principal value upon certain change of controls (in percentage)	101.00%
Maximum increase in downgrade of credit rating of notes to adjust interest rate payable (in percentage)	2.00%
2024 Senior notes
Debt Instrument [Line Items]
Long-term debt, amount	$ 396,553,000	396,117,000
2024 Senior notes \| Genpact Luxembourg S.r.l.
Debt Instrument [Line Items]
Interest rate on senior notes (in percentage)	6.00%
2024 Senior notes \| Genpact Luxembourg and Genpact USA
Debt Instrument [Line Items]
Debt instrument, face amount			$ 400,000,000
Debt amortization expense	$ 3,447,000	3,883,000
Long-term debt, amount	$ 396,553,000	$ 396,117,000
Interest rate on senior notes (in percentage)			6.00%
Total debt issuance cost			$ 4,395,000
2019 Senior notes \| Genpact Luxembourg S.r.l.
Debt Instrument [Line Items]
Maximum increase in downgrade of credit rating of notes to adjust interest rate payable (in percentage)	2.00%

Genpact LTD 10-Q