Financial Derivatives and Hedging Activities - Outstanding Derivatives Used to Hedge Foreign Exchange Risks (Detail)	Sep. 30, 2015 EUR (€)	Sep. 30, 2015 USD ($)	Sep. 30, 2015 PHP	Sep. 30, 2015 CAD	Dec. 31, 2014 EUR (€)	Dec. 31, 2014 USD ($)	Dec. 31, 2014 PHP	Dec. 31, 2014 CAD
Cash Flow Hedges [Member] | Euro / British Pound [Member] | Designated as Hedging [Member] | Sell/Buy - Sell Notional [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative notional amount	€ 9,189,000				€ 4,592,000
Cash Flow Hedges [Member] | Euro / Philippine Peso [Member] | Designated as Hedging [Member] | Sell/Buy - Buy Notional [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative notional amount | PHP			PHP 661,453,000				PHP 523,313,000
Cash Flow Hedges [Member] | British Pound / Philippine Peso [Member] | Designated as Hedging [Member] | Sell/Buy - Buy Notional [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative notional amount | PHP			PHP 471,607,000				PHP 260,535,000
Cash Flow Hedges [Member] | Euro / U.S. Dollar [Member] | Designated as Hedging [Member] | Sell/Buy - Buy Notional [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative notional amount | $		$ 47,751,000				$ 32,527,000
Cash Flow Hedges [Member] | U.S. Dollar / Canadian Dollar [Member] | Designated as Hedging [Member] | Sell/Buy - Buy Notional [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative notional amount | CAD				CAD 19,205,000				CAD 10,036,000
Foreign Currency Hedges [Member] | Euro / British Pound [Member] | Not Designated as Hedging [Member] | Sell/Buy - Sell Notional [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative notional amount					2,000,000
Foreign Currency Hedges [Member] | Euro / U.S. Dollar [Member] | Not Designated as Hedging [Member] | Sell/Buy - Buy Notional [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative notional amount | $		7,000,000
Foreign Currency Hedges [Member] | U.S Dollar / Euro [Member] | Not Designated as Hedging [Member] | Sell/Buy - Sell Notional [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative notional amount | $						4,000,000
Foreign Currency Hedges [Member] | U.S. Dollar / British Pound [Member] | Not Designated as Hedging [Member] | Sell/Buy - Sell Notional [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative notional amount | $		$ 7,000,000				$ 9,000,000
Foreign Currency Hedges [Member] | British Pound / Euro [Member] | Not Designated as Hedging [Member] | Sell/Buy - Sell Notional [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative notional amount	2,000,000
Foreign Currency Hedges [Member] | British Pound / Euro [Member] | Not Designated as Hedging [Member] | Sell/Buy - Buy Notional [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative notional amount	€ 15,500,000				€ 3,000,000