Loans - Nonaccrual Loans and Loans Past Due over 90 Days Still Accruing Interest by Class of Loans (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Financing Receivable, Past Due [Line Items]
Nonaccrual	$ 14,809	$ 14,262
Past Due Over 90 Days Still on Accrual	550	887
Commercial, industrial, and agricultural
Financing Receivable, Past Due [Line Items]
Nonaccrual	3,994	2,076
Past Due Over 90 Days Still on Accrual	443	487
Commercial mortgages
Financing Receivable, Past Due [Line Items]
Nonaccrual	5,299	6,329
Past Due Over 90 Days Still on Accrual	0	53
Residential real estate
Financing Receivable, Past Due [Line Items]
Nonaccrual	4,779	5,187
Past Due Over 90 Days Still on Accrual	62	299
Consumer
Financing Receivable, Past Due [Line Items]
Nonaccrual	737	670
Past Due Over 90 Days Still on Accrual	0	43
Credit Cards
Financing Receivable, Past Due [Line Items]
Nonaccrual	0	0
Past Due Over 90 Days Still on Accrual	$ 45	$ 5