Borrowed Funds - Schedule of Repayment of Long-Term Borrowings for Securities Sold Under Agreements to Repurchase (Detail) - Long-term borrowings [Member] - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
2016	$ 92,500
2017	65,000
2018	100,000
Thereafter	50,000
Securities sold under agreements to repurchase	$ 307,500	$ 462,500