Disclosures about Fair Value of Financial Instruments (Summary of the Company's Financial Instruments) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Fair Value Disclosures [Abstract]
Cash and cash equivalents, Carrying Amount	$ 266,743	$ 253,172	$ 294,335	$ 225,262
Investment in securities, Carrying Amount	390,552	375,696
Loans, net, Carrying Amount	654,691	647,420
Accrued interest receivable, Carrying Amount	6,543	6,647
Assets, Carrying Amount	1,318,529	1,282,935
Cash and cash equivalents, Fair Value	266,743	253,172
Investment in securities, Fair Value	390,552	375,696
Loans, net, Fair Value	652,028	649,161
Accrued interest receivable, Fair Value	6,543	6,647
Assets, Fair Value	1,315,866	1,284,676
Deposits, Carrying Amount	621,961	646,484
Accounts and drafts payable, Carrying Amount	642,287	577,259
Accrued interest payable, Carrying Amount	46	35
Liabilities, Carrying Amount	1,264,294	1,223,778
Deposits, Fair Value	622,173	646,892
Accounts and drafts payable, Fair Value	642,287	577,259
Accrued interest payable, Fair Value	46	35
Liabilities, Fair Value	$ 1,264,506	$ 1,224,186