Borrowings (Summary of Short term and Long term Borrowings and Subordinated Debentures) (Details) - USD ($) $ in Thousands		Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
FHLBB borrowings		$ 25,000
Securities Sold under Agreements to Repurchase		$ 237,984	$ 245,868
FHLBB borrowings
Debt Instrument [Line Items]
Weighted Average Rate (as a percent)		1.87%	1.87%
Long-term Debt and Capital Lease Obligations, Repayments of Principal in Next Twelve Months		$ 10,000
Maturities of Long-term Debt and Capital Lease Obligations [Abstract]
2018		25,000
2019		0
2020		0
Customer repurchase agreements
Maturities of Long-term Debt and Capital Lease Obligations [Abstract]
2018		237,984
FHLBB and correspondent bank overnight borrowings
Maturities of Long-term Debt and Capital Lease Obligations [Abstract]
2018		$ 5,825
Capital lease obligation
Debt Instrument [Line Items]
Weighted Average Rate (as a percent)	[1]	0.00%	4.20%
Maturities of Long-term Debt and Capital Lease Obligations [Abstract]
2018	[1]	$ 0
2019	[1]	0
2020	[1]	0
2021	[1]	0
2022	[1]	0
Thereafter	[1]	$ 0
Long-term Debt
Debt Instrument [Line Items]
Weighted Average Rate (as a percent)		1.87%	2.19%
Long-term Debt and Capital Lease Obligations, Repayments of Principal in Next Twelve Months		$ 10,000
Maturities of Long-term Debt and Capital Lease Obligations [Abstract]
2019		0
2020		0
2021		0
2022		0
Thereafter		0
Total long-term borrowings		$ 10,000	$ 11,580
Long-term Debt | FHLBB borrowings
Debt Instrument [Line Items]
Weighted Average Rate (as a percent)		1.87%	1.87%
Subordinated Debt and Junior Subordinated Debt
Debt Instrument [Line Items]
Weighted Average Rate (as a percent)		5.35%	5.23%
Maturities of Long-term Debt and Capital Lease Obligations [Abstract]
Thereafter		$ 59,080
Total long-term borrowings		$ 59,080	$ 59,067
Subordinated Debt | Subordinated debentures
Debt Instrument [Line Items]
Weighted Average Rate (as a percent)	[2]	5.50%	5.50%
Maturities of Long-term Debt and Capital Lease Obligations [Abstract]
Thereafter	[2]	$ 14,749
Total long-term borrowings	[2]	14,749	$ 14,634
Debt Issuance Costs, Net		251	366
Short-term Debt
Debt Instrument [Line Items]
Total short-term borrowings		$ 268,809	$ 270,868
Weighted Average Rate (as a percent)		1.28%	1.43%
Maturities of Long-term Debt and Capital Lease Obligations [Abstract]
2018		$ 268,809
Short-term Debt | FHLBB borrowings
Debt Instrument [Line Items]
FHLBB borrowings		$ 25,000	$ 25,000
Weighted Average Rate (as a percent)		1.79%	2.71%
Short-term Debt | Customer repurchase agreements
Debt Instrument [Line Items]
Securities Sold under Agreements to Repurchase		$ 237,984	$ 245,868
Short-term Debt | FHLBB and correspondent bank overnight borrowings
Debt Instrument [Line Items]
FHLBB and correspondent bank overnight borrowings		5,825	0
Long-term Debt | FHLBB borrowings
Maturities of Long-term Debt and Capital Lease Obligations [Abstract]
Long-term Federal Home Loan Bank Advances		10,000	10,000
Long-term Debt | Capital lease obligation
Maturities of Long-term Debt and Capital Lease Obligations [Abstract]
Capital lease obligation	[1]	$ 0	$ 1,580
Subsidiary One [Member] | Junior Subordinated Debt
Debt Instrument [Line Items]
Weighted Average Rate (as a percent)		5.50%	5.38%
Maturities of Long-term Debt and Capital Lease Obligations [Abstract]
Thereafter		$ 36,083
Total long-term borrowings		$ 36,083	$ 36,083
Subsidiary Two [Member] | Junior Subordinated Debt
Debt Instrument [Line Items]
Weighted Average Rate (as a percent)		4.45%	4.14%
Maturities of Long-term Debt and Capital Lease Obligations [Abstract]
Thereafter		$ 8,248
Total long-term borrowings		$ 8,248	$ 8,350

[1] (1)Upon adoption of ASU 2016-02, effective January 1, 2019, lease liabilities are presented within other liabilities on the consolidated statements of condition. Refer to Notes 1 and 6 for further information.

[2] (2)The outstanding balance of subordinated debentures was presented net of debt issuance costs of $251,000 and $366,000 at December 31, 2019 and 2018, respectively.