ACL for Loans - Prior Period Adversely Classified Loans (Details) $ in Thousands	Dec. 31, 2020 USD ($)
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	$ 3,087,246
Commercial real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	1,478,235
Commercial and industrial
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	435,660
Commercial construction
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	373,309
SBA Paycheck Protection Program ("PPP")
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	453,084
Residential mortgages
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	252,971
Home equity loans and lines
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	85,006
Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	8,981
Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	52,386
Substandard | Commercial real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	40,088
Substandard | Commercial and industrial
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	7,901
Substandard | Commercial construction
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	3,501
Substandard | SBA Paycheck Protection Program ("PPP")
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	0
Substandard | Residential mortgages
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	474
Substandard | Home equity loans and lines
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	381
Substandard | Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	41
Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	2,490
Doubtful | Commercial real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	197
Doubtful | Commercial and industrial
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	2,293
Doubtful | Commercial construction
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	0
Doubtful | SBA Paycheck Protection Program ("PPP")
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	0
Doubtful | Residential mortgages
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	0
Doubtful | Home equity loans and lines
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	0
Doubtful | Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	0
Loss
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	0
Loss | Commercial real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	0
Loss | Commercial and industrial
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	0
Loss | Commercial construction
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	0
Loss | SBA Paycheck Protection Program ("PPP")
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	0
Loss | Residential mortgages
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	0
Loss | Home equity loans and lines
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	0
Loss | Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	0
Not Adversely Classified
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	3,032,370
Not Adversely Classified | Commercial real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	1,437,950
Not Adversely Classified | Commercial and industrial
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	425,466
Not Adversely Classified | Commercial construction
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	369,808
Not Adversely Classified | SBA Paycheck Protection Program ("PPP")
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	453,084
Not Adversely Classified | Residential mortgages
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	252,497
Not Adversely Classified | Home equity loans and lines
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	84,625
Not Adversely Classified | Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	$ 8,940