Commitments and Contingencies - Gains (Losses) Related to Interest Rate Derivatives Designated as Hedges of Fair Value (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Gain Loss On Fair Value Hedges Recognized In Earnings [Line Items]
Gains (losses) included in the consolidated statements of income	$ 690	$ 158	$ (214)
Fair value hedge | Interest rate swaps | Interest income
Gain Loss On Fair Value Hedges Recognized In Earnings [Line Items]
Gains (losses) included in the consolidated statements of income	320	176	(13)
Fair value hedge | Interest rate swaps | Interest expense
Gain Loss On Fair Value Hedges Recognized In Earnings [Line Items]
Gains (losses) included in the consolidated statements of income	6,670	1,400	9,380
Fair value hedge | Interest rate caps and swaps | Derivatives designated as hedging instruments | Interest income
Gain Loss On Fair Value Hedges Recognized In Earnings [Line Items]
Gains (losses) included in the consolidated statements of income	(320)	(176)	13
Fair value hedge | Interest rate caps and swaps | Derivatives designated as hedging instruments | Interest expense
Gain Loss On Fair Value Hedges Recognized In Earnings [Line Items]
Gains (losses) included in the consolidated statements of income	$ (6,645)	$ (1,473)	$ (9,449)