Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Cash and cash equivalents, Carrying Amount	$ 303,103	$ 253,172	$ 226,082	$ 294,335
Investment securities, Carrying Amount	382,671	375,696
Loans, net, Carrying Amount	674,201	647,420
Accrued interest receivable, Carrying Amount	5,498	6,647
Assets, Carrying Amount	1,365,473	1,282,935
Cash and cash equivalents, Fair Value	303,103	253,172
Investment securities, Fair Value	382,671	375,696
Loans, net, Fair Value	678,185	649,161
Accrued interest receivable, Fair Value	5,498	6,647
Assets, Fair Value	1,369,457	1,284,676
Deposits, Carrying Amount	624,013	646,484
Accounts and drafts payable, Carrying Amount	682,762	577,259
Accrued interest payable, Carrying Amount	40	35
Liabilities, Carrying Amount	1,306,815	1,223,778
Deposits, Fair Value	624,367	646,892
Accounts and drafts payable, Fair Value	682,762	577,259
Accrued interest payable, Fair Value	40	35
Liabilities, Fair Value	$ 1,307,169	$ 1,224,186