Commitments and Contingencies (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Commitments and Contingencies Disclosure [Line Items]
Standby letters of credit extension period	1 year
Operating leases rental expense	$ 4,300	$ 4,000	$ 3,500
Unpaid principal balance of loans repurchased	1,307	524
Reserve for loans repurchases	$ 180	180
Minimum [Member]
Commitments and Contingencies Disclosure [Line Items]
Lease expiration period	7 months
Lease expiration period, renewal option	9 months
Maximum [Member]
Commitments and Contingencies Disclosure [Line Items]
Lease expiration period	23 years
Lease expiration period, renewal option	5 years
Commitments to extend credit on standby letters of credit [Member] | Commitments to Extend Credit [Member]
Commitments and Contingencies Disclosure [Line Items]
Contract Amount	$ 6,666	$ 6,250