Securities (Narrative) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019 USD ($) security	Jan. 01, 2019 USD ($)	Dec. 31, 2018 USD ($) security	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Schedule of Available for Sale and Held to Maturty Securities [Line Items]
Held to maturity debt securities, at amortized cost	$ 0		$ 10,415
Held to maturity debt securities, fair value	0		10,316
Unrealized losses on held to maturity securities, net of tax	(17,503)		(28,309)	$ (32,675)	$ (23,510)
Fair value of available for sale and held to maturity securities pledged as collateral	497,500		$ 439,700
Amortized cost of callable debt securities	273,400
Fair value of callable debt securities	$ 269,800
Number of securities in a continuous unrealized loss position total | security	73		90
Unrealized losses of securities in a continuous unrealized loss position total	$ (12,538)		$ (24,396)
Individual name issuer trust preferred debt securities
Schedule of Available for Sale and Held to Maturty Securities [Line Items]
Number of securities in a continuous unrealized loss position total | security	5		5
Securities in unrealized loss position, number of companies issuing securities | security	4
Amortized cost of trust preferred securities of individual name issuers that are below investment grade	$ 6,100
Unrealized losses of trust preferred securities of individual name issuers that are below investment grade	446
Unrealized losses of securities in a continuous unrealized loss position total	$ (941)		$ (1,535)
Corporate bonds [Member]
Schedule of Available for Sale and Held to Maturty Securities [Line Items]
Number of securities in a continuous unrealized loss position total | security	7		8
Unrealized losses of securities in a continuous unrealized loss position total	$ (1,323)		$ (1,777)
Minimum [Member]
Schedule of Available for Sale and Held to Maturty Securities [Line Items]
Maturity period of callable debt securities	2 months
Call features of callable debt securities	1 month
Maximum [Member]
Schedule of Available for Sale and Held to Maturty Securities [Line Items]
Maturity period of callable debt securities	18 years
Call features of callable debt securities	4 years
Adjustments for Change in Accounting Principle [Domain]
Schedule of Available for Sale and Held to Maturty Securities [Line Items]
Held to maturity debt securities, at amortized cost		$ 10,415
Held to maturity debt securities, fair value		10,316
Unrealized losses on held to maturity securities, net of tax		$ (75)