Commitments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Commitments to extend credit
Schedule of Commitments [Line Items]
Off-balance sheet financial instruments, contractual amounts	$ 1,469,413	$ 1,344,687
Letters of credit
Schedule of Commitments [Line Items]
Off-balance sheet financial instruments, contractual amounts	$ 47,969	44,665
Letters of credit | Minimum
Schedule of Commitments [Line Items]
Remaining term	1 month
Letters of credit | Maximum
Schedule of Commitments [Line Items]
Remaining term	5 years 3 months
State tax credits, held for sale
Schedule of Commitments [Line Items]
Off-balance sheet financial instruments, contractual amounts	$ 28,035	37,473
Low Income Housing Tax Credits [Domain]
Schedule of Commitments [Line Items]
Off-balance sheet financial instruments, contractual amounts	704	4,299
SBIC Capital Commitments [Domain]
Schedule of Commitments [Line Items]
Off-balance sheet financial instruments, contractual amounts	20,829	20,402
Unadvanced Commitment on Impaired Loan
Schedule of Commitments [Line Items]
Estimated losses attributable to unadvanced commitments on impaired loans	400
Fixed Rate Loan Commitment | Commitments to extend credit
Schedule of Commitments [Line Items]
Off-balance sheet financial instruments, contractual amounts	$ 144,800	$ 68,500