Derivatives and Hedging Activities - Summary of Cash Flow Hedges (Detail) - Cash flow hedges [Member] - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Derivatives, Fair Value [Line Items]
Notional Amount, Derivative assets	$ 177,873	$ 545,638
Notional Amount, Derivative liabilities	449,147	42,207
Notional Amount, Total	627,020	587,845
Fair Value, Derivative assets	10,284	44,570
Fair Value, Derivative liabilities	(18,049)	(1,815)
Fair Value, Total	(7,765)	42,755
Unrealized gain (loss) on cash flow hedging instruments, derivative assets	9,375	42,634
Unrealized gain (loss) on cash flow hedging instruments, derivative liabilities	(20,884)	(1,453)
Unrealized gain (loss) on cash flow hedging instruments	(11,509)	41,181
Unrealized gain (loss) on cash flow hedges [Member]
Derivatives, Fair Value [Line Items]
Net loss to be reclassified within 12 months	$ (3,001)	$ 31,900