Financial Derivatives and Hedging Activities - Outstanding Derivatives Used to Hedge Foreign Exchange Risks (Detail)	Jun. 30, 2021 USD ($)	Jun. 30, 2021 EUR (€)	Jun. 30, 2021 PHP (₱)	Jun. 30, 2021 CAD ($)	Jun. 30, 2021 GBP (£)	Dec. 31, 2020 USD ($)	Dec. 31, 2020 EUR (€)	Dec. 31, 2020 PHP (₱)	Dec. 31, 2020 CAD ($)	Dec. 31, 2020 GBP (£)
Cash Flow Hedges [Member] | Philippine Peso / Euro [Member] | Designated as Hedging [Member] | Sell Notional [Member]
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Derivative notional amount | €		€ 53,075,000					€ 18,522,000
Cash Flow Hedges [Member] | Euro / British Pound [Member] | Designated as Hedging [Member] | Sell Notional [Member]
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Derivative notional amount | €		€ 18,653,000					€ 18,638,000
Cash Flow Hedges [Member] | U.S Dollar / Euro [Member] | Designated as Hedging [Member] | Sell Notional [Member]
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Derivative notional amount	$ 658,000					$ 1,041,000
Cash Flow Hedges [Member] | U.S. Dollar / British Pound [Member] | Designated as Hedging [Member] | Sell Notional [Member]
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Derivative notional amount	11,634,000
Cash Flow Hedges [Member] | Canadian Dollar / U.S. Dollar [Member] | Designated as Hedging [Member] | Sell Notional [Member]
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Derivative notional amount						70,000
Cash Flow Hedges [Member] | Euro / Philippine Peso [Member] | Designated as Hedging [Member] | Buy Notional [Member]
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Derivative notional amount | ₱			₱ 924,747,000					₱ 853,686,000
Cash Flow Hedges [Member] | British Pound / Philippine Peso [Member] | Designated as Hedging [Member] | Buy Notional [Member]
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Derivative notional amount | ₱			₱ 1,096,306,000					₱ 1,081,791,000
Cash Flow Hedges [Member] | Euro / U.S. Dollar [Member] | Designated as Hedging [Member] | Buy Notional [Member]
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Derivative notional amount	88,426,000					69,324,000
Cash Flow Hedges [Member] | U.S. Dollar / Canadian Dollar [Member] | Designated as Hedging [Member] | Buy Notional [Member]
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Derivative notional amount				$ 34,749,000					$ 34,847,000
Foreign Currency Hedges [Member] | Euro / British Pound [Member] | Not Designated as Hedging [Member] | Sell Notional [Member]
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Derivative notional amount						600,000
Foreign Currency Hedges [Member] | U.S. Dollar / British Pound [Member] | Not Designated as Hedging [Member] | Sell Notional [Member]
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Derivative notional amount	22,300,000					25,250,000
Foreign Currency Hedges [Member] | Euro / U.S. Dollar [Member] | Not Designated as Hedging [Member] | Buy Notional [Member]
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Derivative notional amount	$ 5,500,000					$ 7,500,000
Foreign Currency Hedges [Member] | British Pound / Euro [Member] | Not Designated as Hedging [Member] | Sell Notional [Member]
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Derivative notional amount | £					£ 1,650,000					£ 1,900,000