Financial Instruments with Off-Balance Sheet Risk (Loan Commitments and Standby Letters of Credit) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Loan Commitments and Standby Letters of Credit [Line Items]
Contractual Loan Commitments		$ 15,000
Unused Commitments to Extend Credit	$ 456,976	473,768
Standby letters of credit	20,873	25,651
Home equity lines of credit
Loan Commitments and Standby Letters of Credit [Line Items]
Contractual Loan Commitments	83,949	85,024
Construction Loans [Member]
Loan Commitments and Standby Letters of Credit [Line Items]
Contractual Loan Commitments	112,475	119,075
Other loan commitments
Loan Commitments and Standby Letters of Credit [Line Items]
Contractual Loan Commitments	$ 260,552	$ 269,669