Loans and Loans Held for Sale - Restructured Loans By Segment and Type of Concession (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021 USD ($) loan	Sep. 30, 2020 USD ($) loan	Sep. 30, 2021 USD ($) loan	Sep. 30, 2020 USD ($) loan
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts | loan	11	14	29	34
Pre-Modification Outstanding Recorded Investment	$ 698	$ 4,693	$ 8,919	$ 13,034
Post-Modification Outstanding Recorded Investment	689	4,561	8,513	11,585
Bankruptcy
Financing Receivable, Troubled Debt Restructuring [Line Items]
Pre-Modification Outstanding Recorded Investment	317	338	866	1,056
Other
Financing Receivable, Troubled Debt Restructuring [Line Items]
Pre-Modification Outstanding Recorded Investment	0	0	80	0
Extend Maturity
Financing Receivable, Troubled Debt Restructuring [Line Items]
Pre-Modification Outstanding Recorded Investment	372	3,936	2,223	10,145
Modify Rate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Pre-Modification Outstanding Recorded Investment	0	0	0	0
Modify Payments
Financing Receivable, Troubled Debt Restructuring [Line Items]
Pre-Modification Outstanding Recorded Investment	$ 0	$ 287	$ 5,343	$ 384
Commercial real estate | Commercial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts | loan	0	0	0	1
Pre-Modification Outstanding Recorded Investment	$ 0	$ 0	$ 0	$ 2,210
Post-Modification Outstanding Recorded Investment	0	0	0	2,210
Commercial real estate | Bankruptcy | Commercial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Pre-Modification Outstanding Recorded Investment	0	0	0	0
Commercial real estate | Other | Commercial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Pre-Modification Outstanding Recorded Investment	0	0	0	0
Commercial real estate | Extend Maturity | Commercial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Pre-Modification Outstanding Recorded Investment	0	0	0	2,210
Commercial real estate | Modify Rate | Commercial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Pre-Modification Outstanding Recorded Investment	0	0	0	0
Commercial real estate | Modify Payments | Commercial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Pre-Modification Outstanding Recorded Investment	$ 0	$ 0	$ 0	$ 0
Commercial and industrial | Commercial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts | loan	2	2	2	3
Pre-Modification Outstanding Recorded Investment	$ 342	$ 4,021	$ 6,304	$ 6,489
Post-Modification Outstanding Recorded Investment	341	4,022	5,968	5,284
Commercial and industrial | Bankruptcy | Commercial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Pre-Modification Outstanding Recorded Investment	0	0	0	0
Commercial and industrial | Other | Commercial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Pre-Modification Outstanding Recorded Investment	0	0	0	0
Commercial and industrial | Extend Maturity | Commercial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Pre-Modification Outstanding Recorded Investment	341	3,735	772	4,997
Commercial and industrial | Modify Rate | Commercial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Pre-Modification Outstanding Recorded Investment	0	0	0	0
Commercial and industrial | Modify Payments | Commercial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Pre-Modification Outstanding Recorded Investment	$ 0	$ 287	$ 5,196	$ 287
Commercial construction | Commercial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts | loan	0	0	0	3
Pre-Modification Outstanding Recorded Investment	$ 0	$ 0	$ 0	$ 2,592
Post-Modification Outstanding Recorded Investment	0	0	0	2,561
Commercial construction | Bankruptcy | Commercial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Pre-Modification Outstanding Recorded Investment	0	0	0	0
Commercial construction | Other | Commercial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Pre-Modification Outstanding Recorded Investment	0	0	0	0
Commercial construction | Extend Maturity | Commercial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Pre-Modification Outstanding Recorded Investment	0	0	0	2,561
Commercial construction | Modify Rate | Commercial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Pre-Modification Outstanding Recorded Investment	0	0	0	0
Commercial construction | Modify Payments | Commercial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Pre-Modification Outstanding Recorded Investment	$ 0	$ 0	$ 0	$ 0
Business banking | Commercial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts | loan	0	1	7	3
Pre-Modification Outstanding Recorded Investment	$ 0	$ 333	$ 1,551	$ 501
Post-Modification Outstanding Recorded Investment	0	171	1,500	268
Business banking | Bankruptcy | Commercial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Pre-Modification Outstanding Recorded Investment	0	0	0	0
Business banking | Other | Commercial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Pre-Modification Outstanding Recorded Investment	0	0	80	0
Business banking | Extend Maturity | Commercial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Pre-Modification Outstanding Recorded Investment	0	171	1,420	171
Business banking | Modify Rate | Commercial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Pre-Modification Outstanding Recorded Investment	0	0	0	0
Business banking | Modify Payments | Commercial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Pre-Modification Outstanding Recorded Investment	$ 0	$ 0	$ 0	$ 97
Consumer real estate | Consumer
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts | loan	9	10	20	23
Pre-Modification Outstanding Recorded Investment	$ 356	$ 334	$ 1,064	$ 1,237
Post-Modification Outstanding Recorded Investment	348	364	1,045	1,258
Consumer real estate | Bankruptcy | Consumer
Financing Receivable, Troubled Debt Restructuring [Line Items]
Pre-Modification Outstanding Recorded Investment	317	334	866	1,052
Consumer real estate | Other | Consumer
Financing Receivable, Troubled Debt Restructuring [Line Items]
Pre-Modification Outstanding Recorded Investment	0	0		0
Consumer real estate | Extend Maturity | Consumer
Financing Receivable, Troubled Debt Restructuring [Line Items]
Pre-Modification Outstanding Recorded Investment	31	30	31	206
Consumer real estate | Modify Rate | Consumer
Financing Receivable, Troubled Debt Restructuring [Line Items]
Pre-Modification Outstanding Recorded Investment	0	0		0
Consumer real estate | Modify Payments | Consumer
Financing Receivable, Troubled Debt Restructuring [Line Items]
Pre-Modification Outstanding Recorded Investment	$ 0	$ 0	$ 147	$ 0
Other consumer | Consumer
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts | loan	0	1	0	1
Pre-Modification Outstanding Recorded Investment	$ 0	$ 5	$ 0	$ 5
Post-Modification Outstanding Recorded Investment	0	4	0	4
Other consumer | Bankruptcy | Consumer
Financing Receivable, Troubled Debt Restructuring [Line Items]
Pre-Modification Outstanding Recorded Investment	0	4	0	4
Other consumer | Other | Consumer
Financing Receivable, Troubled Debt Restructuring [Line Items]
Pre-Modification Outstanding Recorded Investment	0	0	0	0
Other consumer | Extend Maturity | Consumer
Financing Receivable, Troubled Debt Restructuring [Line Items]
Pre-Modification Outstanding Recorded Investment	0	0	0	0
Other consumer | Modify Rate | Consumer
Financing Receivable, Troubled Debt Restructuring [Line Items]
Pre-Modification Outstanding Recorded Investment	0	0	0	0
Other consumer | Modify Payments | Consumer
Financing Receivable, Troubled Debt Restructuring [Line Items]
Pre-Modification Outstanding Recorded Investment	$ 0	$ 0	$ 0	$ 0