Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Cash and cash equivalents, Carrying Amount	$ 199,582	$ 228,110	$ 143,570	$ 266,743
Investment securities, Carrying Amount	454,981	470,523
Loans, net, Carrying Amount	691,790	676,026
Accrued interest receivable, Carrying Amount	6,509	7,413
Assets, Carrying Amount	1,352,862	1,382,072
Cash and cash equivalents, Fair Value	199,582	228,110
Investment securities, Fair Value	454,981	470,523
Loans, net, Fair Value	684,135	675,020
Accrued interest receivable, Fair Value	6,509	7,413
Assets, Fair Value	1,345,207	1,381,066
Deposits, Carrying Amount	639,243	678,088
Accounts and drafts payable, Carrying Amount	747,455	715,888
Accrued interest payable, Carrying Amount	67	55
Liabilities, Carrying Amount	1,386,765	1,340,031
Deposits, Fair Value	635,619	678,346
Accounts and drafts payable, Fair Value	747,455	661,888
Accrued interest payable, Fair Value	67	55
Liabilities, Fair Value	$ 1,383,141	$ 1,340,289