Loans - Allowance for credit loss activity (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020		Dec. 31, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning Allowance	$ 31,243		$ 28,331	$ 26,683
Impact of ASC 326 Adoption	2,354			47
Acquisition related allowance for credit loss (PCD)	7,698
Charge-Offs	(6,352)		(1,725)	(2,874)
Recoveries	3,982		1,732	3,346
Provisions	43,154	[1]	2,905	1,176
Ending Allowance	82,079		31,243	28,331
Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning Allowance	2,867		2,881	2,532
Impact of ASC 326 Adoption	1,765
Acquisition related allowance for credit loss (PCD)	1,077
Charge-Offs	(307)		(515)	(261)
Recoveries	342		193	131
Provisions	11,790	[1]	308	479
Ending Allowance	17,534		2,867	2,881
Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning Allowance	16,302		15,142	13,056
Impact of ASC 326 Adoption	3,682
Acquisition related allowance for credit loss (PCD)	4,053
Charge-Offs	(4,237)		(148)	(1,387)
Recoveries	1,352		645	777
Provisions	22,265	[1]	663	2,696
Ending Allowance	43,417		16,302	15,142
Construction Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning Allowance	996		682	647
Impact of ASC 326 Adoption	(223)
Charge-Offs	(1)
Provisions	1,969	[1]	314	35
Ending Allowance	2,741		996	682
Home Equity and Improvement [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning Allowance	1,700		2,026	2,255
Impact of ASC 326 Adoption	(521)
Acquisition related allowance for credit loss (PCD)	248
Charge-Offs	(164)		(245)	(269)
Recoveries	262		184	191
Provisions	3,214	[1]	(265)	(151)
Ending Allowance	4,739		1,700	2,026
Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning Allowance	9,003		7,281	7,965
Impact of ASC 326 Adoption	(2,263)
Acquisition related allowance for credit loss (PCD)	2,272
Charge-Offs	(1,350)		(528)	(724)
Recoveries	1,850		642	2,221
Provisions	2,153	[1]	1,608	(2,181)
Ending Allowance	11,665		9,003	7,281
Consumer Finance [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning Allowance	375		319	228
Impact of ASC 326 Adoption	(86)
Acquisition related allowance for credit loss (PCD)	48
Charge-Offs	(293)		(289)	(233)
Recoveries	176		68	26
Provisions	1,763	[1]	277	298
Ending Allowance	$ 1,983		$ 375	$ 319

[1] Allowance/provision are not comparable to prior periods due to the adoption of CECL.