Commitments and Contingencies - Total Commitments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Commitments and Contingencies
Total commitments and standby letters of credit	$ 276,184	$ 255,093
Outstanding financial fixed rate commitments	31,200
Outstanding financial variable rate commitments	245,000
Commitments to extend credit
Commitments and Contingencies
Total commitments and standby letters of credit	263,817	242,125
Standby letters of credit
Commitments and Contingencies
Total commitments and standby letters of credit	12,367	12,968
Standby letters of credit | One customer
Commitments and Contingencies
Total commitments and standby letters of credit	$ 10,200	$ 10,400