Derivative Financial Instruments - Additional Information (Detail)	Dec. 31, 2016 USD ($) Agreement	Dec. 31, 2015 USD ($)
Derivative Instruments, Gain (Loss) [Line Items]
Derivative assets and liabilities offset in balance sheet	$ 0
Total notional amount of the Company's swaps	$ 202,700,000	$ 189,000,000
Interest-rate Swap Agreements with Customers [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Number of interest-rate swap agreements | Agreement	83