Derivatives and Hedging Activities - Summary of Cash Flow Hedges (Detail) - Cash flow hedges [Member] - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Derivatives, Fair Value [Line Items]
Notional Amount, Derivative assets	$ 483,110	$ 545,638
Notional Amount, Derivative liabilities	176,432	42,207
Notional Amount, Total	659,542	587,845
Fair Value, Derivative assets	30,350	44,570
Fair Value, Derivative liabilities	(2,315)	(1,815)
Fair Value, Total	28,035	42,755
Unrealized gain (loss) on cash flow hedging instruments, derivative assets	27,744	42,634
Unrealized gain (loss) on cash flow hedging instruments, derivative liabilities	(2,340)	(1,453)
Unrealized gain (loss) on cash flow hedging instruments	25,404	41,181
Unrealized gain (loss) on cash flow hedges [Member]
Derivatives, Fair Value [Line Items]
Net gain to be reclassified within 12 months	$ 23,042	$ 31,900