Derivatives and Hedging Activities - Summary of Cash Flow Hedge Instruments (Detail) - Cash flow hedge instruments - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Notional amount, derivative assets	$ 642,542	$ 72,262
Notional amount, derivative liabilities	118,324	440,637
Notional amount, total	760,866	512,899
Fair value, derivative assets	38,606	2,379
Fair value, derivative liabilities	(865)	(29,777)
Fair value, total	37,741	(27,398)
Accumulated Other Comprehensive Income (Loss) (2)(3)
Derivatives, Fair Value [Line Items]
Fair value, derivative assets	27,968	2,055
Fair value, derivative liabilities	(1,997)	(34,311)
Fair value, total	25,971	(32,256)
Net gain (loss) related to cash flow hedges recorded in accumulated other comprehensive income (loss) that is expected to be recognized in next 12 months	$ 21,400	$ (26,700)