Fair Values of Financial Instruments - Notional Amount of Off-Balance Sheet Commitment Financial Instruments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Fair Values Of Financial Instruments [Line Items]
Fixed Rate	$ 17,147	$ 7,699
Variable Rate	75,379	50,972
Commitments to make loans
Fair Values Of Financial Instruments [Line Items]
Fixed Rate	11,940	1,197
Variable Rate	12,785	2,298
Unused lines of credit
Fair Values Of Financial Instruments [Line Items]
Fixed Rate	5,207	6,502
Variable Rate	$ 62,594	$ 48,674