Borrowed Funds - Schedule of Repayment of Long-Term Borrowings for Securities Sold Under Agreements to Repurchase (Detail) - Long-term borrowings - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
2017	$ 65,000
2018	50,000
Thereafter	50,000
Securities sold under agreements to repurchase	$ 165,000	$ 307,500