Loans (Narrative) (Details) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Jul. 01, 2018
Financing Receivable, Recorded Investment [Line Items]
Business Combination, Acquired Receivable, Fair Value	$ 272,800,000		$ 272,800,000
Business Combination, Acquired Receivables, Gross Contractual Amount	277,900,000		277,900,000			$ 277,900,000
Loans and Leases Receivable, Deferred Income	12,400,000		12,400,000		$ 12,200,000
Goodwill, Purchase Accounting Adjustments			5,100,000
Troubled Debt Restructuring, Classification removed	200,000		2,400,000	$ 0
Partial Charge-Offs On Impaired Loans			11,069,000		10,040,000
Impaired Financing Receivable, Related Allowance	1,846,000		1,846,000		684,000
Recorded investment, related to loans	5,200,000		5,200,000		3,500,000
Troubled Debt Restructuring Included In Nonaccrual Loans	25,200,000		25,200,000		38,500,000
TDRs included in accruing loan totals	14,700,000		14,700,000		20,200,000
Nonaccrual Trouble Debt Restructuring Current	19,400,000		19,400,000		32,400,000
Commitments to lend additional funds to borrowers whose terms had been modified in a TDR	200,000		200,000		1,300,000
Specific reserves related to troubled debt restructuring	900,000		900,000		500,000
Additional Specific Reserves Related To Troubled Debt Restructuring	150,000	$ 0	160,000	290,000
Financing Receivable, Modifications, Recorded Investment, During Period	3,704,000	4,938,000	6,566,000	10,765,000
Loan Modifications on Nonacrrual status	100,000	500,000	$ 500,000	3,000,000
Loan past due period before entering default status			30 days
Financing Receivable, Modifications, Subsequent Default, Recorded Investment, During Period	1,112,000	825,000	$ 1,290,000	1,088,000
Deposit Liabilities Reclassified as Loans Receivable	1,100,000		1,100,000		1,900,000
Financing Receivable With No Related Allowance Recorded [Member]
Financing Receivable, Recorded Investment [Line Items]
Partial Charge-Offs On Impaired Loans			8,900,000		7,900,000
Financing Receivable With A Related Allowance Recorded [Member]
Financing Receivable, Recorded Investment [Line Items]
Partial Charge-Offs On Impaired Loans			2,100,000
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Modifications, Recorded Investment, During Period	1,154,000	1,455,000	1,859,000	2,320,000
Commercial Real Estate [Member] | Financing Receivable With No Related Allowance Recorded [Member]
Financing Receivable, Recorded Investment [Line Items]
Impaired Financing Receivable, Related Allowance	0		0		0
Commercial Real Estate [Member] | Financing Receivable With A Related Allowance Recorded [Member]
Financing Receivable, Recorded Investment [Line Items]
Impaired Financing Receivable, Related Allowance	71,000		71,000		$ 2,000
Accruing [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Modifications, Recorded Investment, During Period	897,000	2,061,000	2,043,000	3,608,000
Loans modified during period	67,000		67,000	2,000
Accruing [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Modifications, Recorded Investment, During Period		974,000	447,000	1,525,000
Nonaccrual [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Modifications, Recorded Investment, During Period	2,807,000	2,877,000	4,523,000	7,157,000
Loans modified during period	1,000,000		1,200,000	1,100,000
Nonaccrual [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Modifications, Recorded Investment, During Period	1,154,000	481,000	1,412,000	795,000
Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Modifications, Recorded Investment, During Period	6,600,000	3,100,000	17,000,000	6,700,000
Commercial Portfolio Segment [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Modifications, Recorded Investment, During Period	0	$ 918,000	200,000	$ 1,000,000
Financial Asset Acquired with Credit Deterioration [Member]
Financing Receivable, Recorded Investment [Line Items]
Business Combination, Acquired Receivable, Fair Value	4,500,000		4,500,000			4,900,000
Business Combination, Acquired Receivables, Gross Contractual Amount	$ 4,700,000		$ 4,700,000			$ 5,100,000