Loans and Allowance for Credit Losses Allowance for Loan Losses by Portfolio Segment (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	$ 166,209	$ 169,410
Loans charged off	14,003
Recoveries of loans previously charged off	2,887
Current period net charge-offs	(11,116)
Provision for credit losses	44,029
Ending balance	257,471	170,372
Beginning balance	163,622	160,537
Loans charged off		(6,369)
Recovery of loans previously charged off		2,231
Net loans recovered (charged off)		(4,138)
Allowance for loan and lease losses, provision for loss, net of provision applied to unfunded commitments		5,710
Ending balance	238,508	162,109
Real-estate - commercial mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance		52,889
Loans charged off		(1,145)
Recovery of loans previously charged off		136
Net loans recovered (charged off)		(1,009)
Allowance for loan and lease losses, provision for loss, net of provision applied to unfunded commitments		66
Ending balance		51,946
Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance		58,868
Loans charged off		(2,787)
Recovery of loans previously charged off		1,243
Net loans recovered (charged off)		(1,544)
Allowance for loan and lease losses, provision for loss, net of provision applied to unfunded commitments		3,177
Ending balance		60,501
Real-estate - home equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance		18,911
Loans charged off		(219)
Recovery of loans previously charged off		197
Net loans recovered (charged off)		(22)
Allowance for loan and lease losses, provision for loss, net of provision applied to unfunded commitments		326
Ending balance		19,215
Real estate - residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance		18,921
Loans charged off		(655)
Recovery of loans previously charged off		132
Net loans recovered (charged off)		(523)
Allowance for loan and lease losses, provision for loss, net of provision applied to unfunded commitments		748
Ending balance		19,146
Real estate - construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance		5,061
Loans charged off		(95)
Recovery of loans previously charged off		84
Net loans recovered (charged off)		(11)
Allowance for loan and lease losses, provision for loss, net of provision applied to unfunded commitments		(109)
Ending balance		4,941
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance		3,217
Loans charged off		(683)
Recovery of loans previously charged off		210
Net loans recovered (charged off)		(473)
Allowance for loan and lease losses, provision for loss, net of provision applied to unfunded commitments		575
Ending balance		3,319
Equipment lease financing, other and overdrafts
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance		2,670
Loans charged off		(785)
Recovery of loans previously charged off		229
Net loans recovered (charged off)		(556)
Allowance for loan and lease losses, provision for loss, net of provision applied to unfunded commitments		927
Ending balance		$ 3,041
Cumulative Effect, Period of Adoption, Adjustment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	58,349
Loans - Excluding OBS Credit Exposure [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	163,622
Loans charged off	14,003
Recoveries of loans previously charged off	2,887
Current period net charge-offs	(11,116)
Provision for credit losses	40,279
Ending balance	238,508
Loans - Excluding OBS Credit Exposure [Member] | Real-estate - commercial mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	45,610
Loans charged off	855
Recoveries of loans previously charged off	244
Current period net charge-offs	(611)
Provision for credit losses	15,959
Ending balance	90,319
Loans - Excluding OBS Credit Exposure [Member] | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	68,602
Loans charged off	10,899
Recoveries of loans previously charged off	1,734
Current period net charge-offs	(9,165)
Provision for credit losses	22,745
Ending balance	63,606
Loans - Excluding OBS Credit Exposure [Member] | Real-estate - home equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	17,744
Loans charged off	316
Recoveries of loans previously charged off	646
Current period net charge-offs	330
Provision for credit losses	(2,756)
Ending balance	15,253
Loans - Excluding OBS Credit Exposure [Member] | Real estate - residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	19,771
Loans charged off	187
Recoveries of loans previously charged off	85
Current period net charge-offs	(102)
Provision for credit losses	1,523
Ending balance	42,427
Loans - Excluding OBS Credit Exposure [Member] | Real estate - construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	4,443
Loans charged off	0
Recoveries of loans previously charged off	70
Current period net charge-offs	70
Provision for credit losses	(130)
Ending balance	8,398
Loans - Excluding OBS Credit Exposure [Member] | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	3,762
Loans charged off	1,213
Recoveries of loans previously charged off	0
Current period net charge-offs	(1,213)
Provision for credit losses	1,347
Ending balance	9,865
Loans - Excluding OBS Credit Exposure [Member] | Equipment lease financing, other and overdrafts
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	3,690
Loans charged off	533
Recoveries of loans previously charged off	108
Current period net charge-offs	(425)
Provision for credit losses	1,591
Ending balance	8,640
Loans - Excluding OBS Credit Exposure [Member] | Cumulative Effect, Period of Adoption, Adjustment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	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
Loans - Excluding OBS Credit Exposure [Member] | Cumulative Effect, Period of Adoption, Adjustment | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	(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)
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
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
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
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