Derivative Financial Instruments - Impact of Derivatives on Consolidated Balance Sheet (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Derivatives, Fair Value [Line Items]
Derivative Assets	$ 43,410	$ 15,314
Interest rate swaps
Derivatives, Fair Value [Line Items]
Derivative Assets	43,410	15,314
Derivative Liabilities	(52,578)	(30,497)
Total net derivatives	(9,168)	(15,183)
Interest rate swaps | Trading
Derivatives, Fair Value [Line Items]
Derivative Assets	414	83
Derivative Liabilities	(194)	(646)
Total net derivatives	220	(563)
Interest rate swaps | Cash Flow | Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative Assets	0	0
Derivative Liabilities	(52,197)	(27,512)
Total net derivatives	(52,197)	(27,512)
Interest rate swaps | Fair Value | Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative Assets	42,996	15,231
Derivative Liabilities	(187)	(2,339)
Total net derivatives	$ 42,809	$ 12,892