Guarantees (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018
Commitments to Extend Credit
Loan Commitments and Letters of Credit [Line Items]
Notional Amount	$ 310,749	$ 321,143	$ 328,774
Fair Value	0	0	0
Standby Letters of Credit
Loan Commitments and Letters of Credit [Line Items]
Notional Amount	4,431	4,466	3,584
Fair Value	$ 20	$ 12	$ 24
Minimum | Standby Letters of Credit
Loan Commitments and Letters of Credit [Line Items]
Loan commitments, fixed fee percent	1.00%
Maximum | Standby Letters of Credit
Loan Commitments and Letters of Credit [Line Items]
Loan commitments, fixed fee percent	3.00%