Derivative Instruments and Hedging Activities - Schedule of Gross Amounts of Derivative Assets and Derivative Liabilities (Detail) - Not Designated as Hedging Instruments - USD ($) $ in Thousands		Sep. 30, 2016	Dec. 31, 2015
Other Assets
Derivative Asset [Abstract]
Gross amounts recognized		$ 15,255	$ 11,295
Gross amounts offset		0	0
Net amounts presented in the Consolidated Balance Sheets		15,255	11,295
Net Amount		15,255	11,295
Derivative Liability [Abstract]
Gross amounts not offset	[1]	0	0
Other Liabilities
Derivative Liability [Abstract]
Gross amounts recognized		15,202	11,276
Gross amounts offset		0	0
Net amounts presented in the Consolidated Balance Sheets		15,202	11,276
Gross amounts not offset	[1]	(14,542)	(12,573)
Net Amount		$ 660	$ (1,297)

[1] Amounts represent posted collateral.