Derivative financial instruments - Schedule of Aggregate Notional Principal Amounts of Outstanding Derivative Financial Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025
Derivative [Line Items]
Notional principal amounts	$ 4,085,590	$ 4,449,720
Balance sheet exposure asset (liability)	(182,109)	(89,569)
United States Dollars (sell) Indian Rupees (buy)
Derivative [Line Items]
Notional principal amounts	2,537,209	2,771,310
Balance sheet exposure asset (liability)	(167,737)	(72,843)
United States Dollars (sell) Mexican Peso (buy)
Derivative [Line Items]
Notional principal amounts	60,900	71,400
Balance sheet exposure asset (liability)	2,585	2,201
United States Dollars (sell) Philippines Peso (buy)
Derivative [Line Items]
Notional principal amounts	214,050	234,000
Balance sheet exposure asset (liability)	(9,427)	(5,739)
Euro (sell) United States Dollars (buy)
Derivative [Line Items]
Notional principal amounts	422,290	446,846
Balance sheet exposure asset (liability)	269	(9,636)
Euro (sell) Romanian Leu (buy)
Derivative [Line Items]
Notional principal amounts	46,449	63,353
Balance sheet exposure asset (liability)	478	143
Japanese Yen (sell) Chinese Renminbi (buy)
Derivative [Line Items]
Notional principal amounts	71,212	67,617
Balance sheet exposure asset (liability)	5,109	3,746
United States Dollars (sell) Chinese Renminbi (buy)
Derivative [Line Items]
Notional principal amounts	72,300	82,800
Balance sheet exposure asset (liability)	1,108	144
Pound Sterling (sell) United States Dollars (buy)
Derivative [Line Items]
Notional principal amounts	80,245	92,322
Balance sheet exposure asset (liability)	1,263	(279)
United States Dollars (sell) Hungarian Forint (buy)
Derivative [Line Items]
Notional principal amounts	24,000	33,000
Balance sheet exposure asset (liability)	1,688	2,524
Australian Dollars (sell) Indian Rupees (buy)
Derivative [Line Items]
Notional principal amounts	186,385	189,797
Balance sheet exposure asset (liability)	(17,613)	(8,204)
United States Dollars (sell) Polish Zloty (buy)
Derivative [Line Items]
Notional principal amounts	35,250	42,000
Balance sheet exposure asset (liability)	375	1,884
Japanese Yen (sell) United States Dollars (buy)
Derivative [Line Items]
Notional principal amounts	0	7,000
Balance sheet exposure asset (liability)	0	238
Israeli Shekel (buy) United States Dollars (sell)
Derivative [Line Items]
Notional principal amounts	20,000	30,000
Balance sheet exposure asset (liability)	527	1,025
South African Rand (sell) United States Dollars (buy)
Derivative [Line Items]
Notional principal amounts	18,000	18,000
Balance sheet exposure asset (liability)	(836)	(1,186)
United States Dollars (sell) Brazilian Real (buy)
Derivative [Line Items]
Notional principal amounts	4,000	4,000
Balance sheet exposure asset (liability)	136	(46)
United States Dollars (sell) Costa Rica Colon (buy)
Derivative [Line Items]
Notional principal amounts	44,300	44,400
Balance sheet exposure asset (liability)	2,838	773
United States Dollars (sell) Canadian Dollar (buy)
Derivative [Line Items]
Notional principal amounts	9,000	9,000
Balance sheet exposure asset (liability)	38	193
United States Dollars (sell) Malaysian Ringgit (buy)
Derivative [Line Items]
Notional principal amounts	21,250	21,000
Balance sheet exposure asset (liability)	343	486
Interest rate swaps (floating to fixed)
Derivative [Line Items]
Notional principal amounts	218,750	221,875
Balance sheet exposure asset (liability)	$ (3,253)	$ (4,993)

Fair value of credit risk derivative asset after deduction of credit risk derivative liability.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4K
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480434/815-10-50-4K

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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

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 815
-SubTopic 20
-Name Accounting Standards Codification
-Section 25
-Paragraph 6A
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480682/815-20-25-6A

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480237/815-40-50-5

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- Definition

Nominal or face amount used to calculate payment on derivative.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 181
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480401/815-10-55-181

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480434/815-10-50-1B

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1A
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480434/815-10-50-1A

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