Loans - Schedule of Loan Assigned Risk Rating within 12 Months of Balance Sheet Date (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Financing Receivable, Recorded Investment [Line Items]
Net loans	$ 2,505,744	$ 2,454,853
Pass
Financing Receivable, Recorded Investment [Line Items]
Net loans	1,612,205	1,572,960
Special Mention
Financing Receivable, Recorded Investment [Line Items]
Net loans	19,186	13,760
Substandard
Financing Receivable, Recorded Investment [Line Items]
Net loans	29,200	27,353
Doubtful
Financing Receivable, Recorded Investment [Line Items]
Net loans	0	0
Pass, Special Mention, Substandard, Doubtful
Financing Receivable, Recorded Investment [Line Items]
Net loans	1,660,591	1,614,073
Commercial, industrial, and agricultural
Financing Receivable, Recorded Investment [Line Items]
Net loans	950,865	916,297
Commercial, industrial, and agricultural | Pass
Financing Receivable, Recorded Investment [Line Items]
Net loans	922,618	889,547
Commercial, industrial, and agricultural | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Net loans	10,149	10,519
Commercial, industrial, and agricultural | Substandard
Financing Receivable, Recorded Investment [Line Items]
Net loans	18,098	16,231
Commercial, industrial, and agricultural | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Net loans	0	0
Commercial mortgages
Financing Receivable, Recorded Investment [Line Items]
Net loans	709,726	697,776
Commercial mortgages | Pass
Financing Receivable, Recorded Investment [Line Items]
Net loans	689,587	683,413
Commercial mortgages | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Net loans	9,037	3,241
Commercial mortgages | Substandard
Financing Receivable, Recorded Investment [Line Items]
Net loans	11,102	11,122
Commercial mortgages | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Net loans	$ 0	$ 0