Commitments and Contingencies (Financial Instruments with Off Balance Sheet Risk) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Interest rate lock commitments [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Notional amount	$ 30,766	$ 45,139
Commitments to sell mortgage loans [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Notional amount	61,993	71,539
Interest rate swaps with customers [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Notional amount	648,050	545,049
Mirror swaps with counterparties [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Notional amount	648,050	545,049
Risk participation-in agreement [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Notional amount	46,510	34,052
Foreign exchange contracts [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Notional amount	2,784	3,005
Interest rate swaps [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Notional amount	60,000	60,000
Commitments to Extend Credit [Member] | Commitments to extend credit on commerical loans [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Contract Amount	533,884	537,310
Commitments to Extend Credit [Member] | Commitments to extend credit on home equity lines [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Contract Amount	270,462	254,855
Commitments to Extend Credit [Member] | Commitments to extend credit on other loans [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Contract Amount	46,698	48,819
Commitments to Extend Credit [Member] | Commitments to extend credit on standby letters of credit [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Contract Amount	$ 7,706	$ 6,666