Derivative Financial Instruments - Notional Amount and Fair Value of Foreign Currency Forward Contract (Detail) In Thousands, unless otherwise specified	Sep. 30, 2014 Financial Institution Counterparties [Member] Other Assets [Member] Non Designated as Hedging Instrument [Member] CAD	Sep. 30, 2014 Financial Institution Counterparties [Member] Other Assets [Member] Non Designated as Hedging Instrument [Member] EUR (€)	Sep. 30, 2014 Financial Institution Counterparties [Member] Other Assets [Member] Non Designated as Hedging Instrument [Member] GBP (£)	Dec. 31, 2013 Financial Institution Counterparties [Member] Other Assets [Member] Non Designated as Hedging Instrument [Member] CAD	Dec. 31, 2013 Financial Institution Counterparties [Member] Other Assets [Member] Non Designated as Hedging Instrument [Member] EUR (€)	Dec. 31, 2013 Financial Institution Counterparties [Member] Other Assets [Member] Non Designated as Hedging Instrument [Member] GBP (£)	Sep. 30, 2014 Financial Institution Counterparties [Member] Other Liabilities [Member] Non Designated as Hedging Instrument [Member] CAD	Sep. 30, 2014 Financial Institution Counterparties [Member] Other Liabilities [Member] Non Designated as Hedging Instrument [Member] EUR (€)	Dec. 31, 2013 Financial Institution Counterparties [Member] Other Liabilities [Member] Non Designated as Hedging Instrument [Member] CAD	Dec. 31, 2013 Financial Institution Counterparties [Member] Other Liabilities [Member] Non Designated as Hedging Instrument [Member] EUR (€)	Sep. 30, 2014 Customer Counterparties [Member] Other Assets [Member] Non Designated as Hedging Instrument [Member] CAD	Dec. 31, 2013 Customer Counterparties [Member] Other Assets [Member] Non Designated as Hedging Instrument [Member] CAD	Sep. 30, 2014 Customer Counterparties [Member] Other Liabilities [Member] Non Designated as Hedging Instrument [Member] CAD	Dec. 31, 2013 Customer Counterparties [Member] Other Liabilities [Member] Non Designated as Hedging Instrument [Member] CAD	Sep. 30, 2014 Foreign Exchange Forward [Member] Financial Institution Counterparties [Member] USD ($)	Dec. 31, 2013 Foreign Exchange Forward [Member] Financial Institution Counterparties [Member] USD ($)	Sep. 30, 2014 Foreign Exchange Forward [Member] Customer Counterparties [Member] USD ($)	Dec. 31, 2013 Foreign Exchange Forward [Member] Customer Counterparties [Member] USD ($)	Sep. 30, 2014 GBP Foreign Exchange Forward [Member] Financial Institution Counterparties [Member] USD ($)	Dec. 31, 2013 GBP Foreign Exchange Forward [Member] Financial Institution Counterparties [Member] USD ($)	Sep. 30, 2014 Eurodollar Foreign Exchange Forward [Member] [Member] Financial Institution Counterparties [Member] USD ($)	Dec. 31, 2013 Eurodollar Foreign Exchange Forward [Member] [Member] Financial Institution Counterparties [Member] USD ($)
Derivative Counter Party [Line Items]
Forward Contracts – Assets Notional Amount	27,571	€ 967	£ 501	18,886	€ 1,175	£ 0					0	14,055
Forward Contracts – Liability Notional Amount							0	0	14,078	494			27,528	18,859
Forward Contracts – Assets Estimated Fair Value															816	85	0	45			7	5
Forward Contracts – Liability Estimated Fair Value															$ 0	$ (23)	$ (773)	$ (58)	$ 0	$ 0	$ 0	$ (4)