Borrowed Funds - Scheduled Securities Sold Under Repurchase Agreements (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Total scheduled maturities of securities	$ 261,350	$ 246,571
Securities Sold Under Repurchase Agreements [Member]
Debt Instrument [Line Items]
Due in one year or less	181,350
Due after one year through two years	25,000
Due after two years through three years	20,000
Due after three years through four years	35,000
Due after four years through five years	0
Thereafter	0
Total scheduled maturities of securities	$ 261,350