Loans and Allowance for Credit Losses Allowance for Loan Losses by Portfolio Segment (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance			$ 277,567
Loans charged off	$ 9,522	$ 8,047	17,724	$ 22,050
Recoveries of loans previously charged off	2,568	3,926	4,589	6,813
Total net (charge-offs) recoveries	(6,954)	(4,121)	(13,135)	(15,237)
Provision for credit losses	(3,500)	19,570	(9,000)	63,600
Ending balance	255,032		255,032		$ 277,567
Loans - Excluding OBS Credit Exposure [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	265,986	238,508	277,567	163,622	163,622
Loans charged off	9,522	8,047	17,724	22,050
Recoveries of loans previously charged off	2,568	3,926	4,589	6,813
Total net (charge-offs) recoveries	(6,954)	(4,121)	(13,135)	(15,237)
Provision for credit losses	(4,000)	22,150	(9,400)	62,429
Ending balance	255,032	256,537	255,032	256,537	277,567
Loans - Excluding OBS Credit Exposure [Member] | Real estate - commercial mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	100,976	90,319	103,425	45,610	45,610
Loans charged off	6,506	2,324	8,343	3,179
Recoveries of loans previously charged off	729	95	903	339
Total net (charge-offs) recoveries	(5,777)	(2,229)	(7,440)	(2,840)
Provision for credit losses	182	14,605	(604)	30,564
Ending balance	95,381	102,695	95,381	102,695	103,425
Loans - Excluding OBS Credit Exposure [Member] | Commercial and industrial (1)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	71,194	63,606	74,771	68,602	68,602
Loans charged off	954	3,480	5,273	14,379
Recoveries of loans previously charged off	693	2,978	1,462	4,712
Total net (charge-offs) recoveries	(261)	(502)	(3,811)	(9,667)
Provision for credit losses	(5,529)	(1,657)	(5,556)	21,088
Ending balance	65,404	61,447	65,404	61,447	74,771
Loans - Excluding OBS Credit Exposure [Member] | Real-estate - home equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	13,730	15,253	14,232	17,744	17,744
Loans charged off	212	458	424	745
Recoveries of loans previously charged off	58	44	109	261
Total net (charge-offs) recoveries	(154)	(414)	(315)	(484)
Provision for credit losses	(983)	1,552	(1,324)	(804)
Ending balance	12,593	16,391	12,593	16,391	14,232
Loans - Excluding OBS Credit Exposure [Member] | Real estate - residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	49,995	42,427	51,995	19,771	19,771
Loans charged off	496	235	688	422
Recoveries of loans previously charged off	105	112	200	197
Total net (charge-offs) recoveries	(391)	(123)	(488)	(225)
Provision for credit losses	4,584	4,139	2,681	5,662
Ending balance	54,188	46,443	54,188	46,443	51,995
Loans - Excluding OBS Credit Exposure [Member] | Real-estate - construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	15,079	8,398	15,608	4,443	4,443
Loans charged off	0	17	39	17
Recoveries of loans previously charged off	254	0	638	70
Total net (charge-offs) recoveries	254	(17)	599	53
Provision for credit losses	(2,679)	3,933	(3,553)	3,803
Ending balance	12,654	12,314	12,654	12,314	15,608
Loans - Excluding OBS Credit Exposure [Member] | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	9,412	9,865	10,905	3,762	3,762
Loans charged off	918	845	1,553	2,087
Recoveries of loans previously charged off	576	605	965	1,034
Total net (charge-offs) recoveries	(342)	(240)	(588)	(1,053)
Provision for credit losses	331	674	(916)	1,621
Ending balance	9,401	10,299	9,401	10,299	10,905
Loans - Excluding OBS Credit Exposure [Member] | Equipment lease financing, other and overdrafts
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	5,600	8,640	6,631	3,690	3,690
Loans charged off	436	688	1,404	1,221
Recoveries of loans previously charged off	153	92	312	200
Total net (charge-offs) recoveries	(283)	(596)	(1,092)	(1,021)
Provision for credit losses	94	(1,096)	(128)	495
Ending balance	$ 5,411	$ 6,948	$ 5,411	6,948	6,631
Loans - Excluding OBS Credit Exposure [Member] | Cumulative Effect, Period of Adoption, Adjustment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance				45,723	45,723
Loans - Excluding OBS Credit Exposure [Member] | Cumulative Effect, Period of Adoption, Adjustment | Real estate - commercial mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance				29,361	29,361
Loans - Excluding OBS Credit Exposure [Member] | Cumulative Effect, Period of Adoption, Adjustment | Commercial and industrial (1)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance				(18,576)	(18,576)
Loans - Excluding OBS Credit Exposure [Member] | Cumulative Effect, Period of Adoption, Adjustment | Real-estate - home equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance				(65)	(65)
Loans - Excluding OBS Credit Exposure [Member] | Cumulative Effect, Period of Adoption, Adjustment | Real estate - residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance				21,235	21,235
Loans - Excluding OBS Credit Exposure [Member] | Cumulative Effect, Period of Adoption, Adjustment | Real-estate - construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance				4,015	4,015
Loans - Excluding OBS Credit Exposure [Member] | Cumulative Effect, Period of Adoption, Adjustment | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance				5,969	5,969
Loans - Excluding OBS Credit Exposure [Member] | Cumulative Effect, Period of Adoption, Adjustment | Equipment lease financing, other and overdrafts
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance				$ 3,784	$ 3,784