Derivative Financial Instruments - Impact of Derivatives on Consolidated Balance Sheet (Detail) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Derivatives, Fair Value [Line Items]
Derivative Assets	$ 52,007	$ 15,314
Derivative Liabilities	(52,250)	(30,497)
Interest rate swaps
Derivatives, Fair Value [Line Items]
Derivative Assets	52,007	15,314
Derivative Liabilities	(52,250)	(30,497)
Total net derivatives	(243)	(15,183)
Interest rate swaps | Trading
Derivatives, Fair Value [Line Items]
Derivative Assets	1,225	83
Derivative Liabilities	(135)	(646)
Total net derivatives	1,090	(563)
Interest rate swaps | Cash Flow | Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative Assets	0	0
Derivative Liabilities	(51,955)	(27,512)
Total net derivatives	(51,955)	(27,512)
Interest rate swaps | Fair Value | Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative Assets	50,782	15,231
Derivative Liabilities	(160)	(2,339)
Total net derivatives	$ 50,622	$ 12,892