Commitments - Summary of Financial instruments Whose Contract Amount Represents Credit Risk (Details) - Credit Risk - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Line Of Credit Facility [Line Items]
Contractual amount of financial instruments	$ 110,783	$ 104,173
Stand-by and Performance Letter of Credit
Line Of Credit Facility [Line Items]
Contractual amount of financial instruments	2,219	2,935
Commitments to Extend Credit
Line Of Credit Facility [Line Items]
Contractual amount of financial instruments	$ 108,564	$ 101,238