Loans and Allowance for Credit Losses - Allowance for Loan Losses by Portfolio Segment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	$ 269,366	$ 249,001	$ 277,567
Loans charged off	39,201	21,472
Recoveries of loans previously charged off	10,129	14,092
Net loans recovered (charged off)			(13,806)
Loans - Excluding OBS Credit Exposure
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance		249,001
Beginning balance	269,366
Loans charged off	39,201	21,472
Recoveries of loans previously charged off	10,129	14,092
Net loans recovered (charged off)	(29,072)	(7,380)
Provision for credit losses	53,110	18,656
Ending balance	293,404	269,366
Allowance for credit losses at acquisition		1,135
Real estate - commercial mortgage | Loans - Excluding OBS Credit Exposure
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance		87,970
Beginning balance	69,456
Loans charged off	17,999	12,473
Recoveries of loans previously charged off	1,076	3,860
Net loans recovered (charged off)	(16,923)	(8,613)
Provision for credit losses	60,032	(15,059)
Ending balance	112,565	69,456
Allowance for credit losses at acquisition		1,051
Commercial and Industrial | Loans - Excluding OBS Credit Exposure
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance		67,056
Beginning balance	70,116
Loans charged off	9,246	2,390
Recoveries of loans previously charged off	3,473	5,893
Net loans recovered (charged off)	(5,773)	3,503
Provision for credit losses	9,923	(443)
Ending balance	74,266	70,116
Allowance for credit losses at acquisition		0
Real-estate - home equity | Loans - Excluding OBS Credit Exposure
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance		19,749
Beginning balance	26,429
Loans charged off	7,514	4,412
Recoveries of loans previously charged off	3,198	2,581
Net loans recovered (charged off)	(4,316)	(1,831)
Provision for credit losses	(4,509)	8,373
Ending balance	17,604	26,429
Financing Receivable, Provision Expense		131
Allowance for credit losses at acquisition		7
Real estate – residential mortgage | Loans - Excluding OBS Credit Exposure
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance		54,236
Beginning balance	83,250
Loans charged off	62	66
Recoveries of loans previously charged off	421	425
Net loans recovered (charged off)	359	359
Provision for credit losses	(10,323)	24,862
Ending balance	73,286	83,250
Financing Receivable, Provision Expense		3,716
Allowance for credit losses at acquisition		77
Real-estate - construction | Loans - Excluding OBS Credit Exposure
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance		12,941
Beginning balance	10,743
Loans charged off	0	0
Recoveries of loans previously charged off	858	574
Net loans recovered (charged off)	858	574
Provision for credit losses	694	(2,772)
Ending balance	12,295	10,743
Allowance for credit losses at acquisition		0
Leases and other loans | Loans - Excluding OBS Credit Exposure
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance		7,049
Beginning balance	9,372
Loans charged off	4,380	2,131
Recoveries of loans previously charged off	1,103	759
Net loans recovered (charged off)	(3,277)	(1,372)
Provision for credit losses	(2,707)	3,695
Ending balance	$ 3,388	9,372
Allowance for credit losses at acquisition		0
Cumulative Effect, Period of Adoption, Adjustment | Loans - Excluding OBS Credit Exposure
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance		7,954
Ending balance			7,954
Cumulative Effect, Period of Adoption, Adjustment | Real estate - commercial mortgage | Loans - Excluding OBS Credit Exposure
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance		4,107
Ending balance			4,107
Cumulative Effect, Period of Adoption, Adjustment | Commercial and Industrial | Loans - Excluding OBS Credit Exposure
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance		0
Ending balance			0
Cumulative Effect, Period of Adoption, Adjustment | Real-estate - construction | Loans - Excluding OBS Credit Exposure
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance		0
Ending balance			0
Cumulative Effect, Period of Adoption, Adjustment | Leases and other loans | Loans - Excluding OBS Credit Exposure
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance		$ 0
Ending balance			$ 0