Summary of Significant Accounting Policies, Credit Loss Adoption Impact (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Jan. 01, 2020	Dec. 31, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for Loan Losses			$ 201,371
Allowance for Unfunded Commitments	$ 64,776		21,907
Total commercial
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for Loan Losses			166,846
Allowance for Unfunded Commitments			20,465
Total consumer
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for Loan Losses			34,525
Allowance for Unfunded Commitments			1,443
Commercial and industrial | Total commercial
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for Loan Losses			91,133
Allowance for Unfunded Commitments			12,276
Commercial real estate — owner occupied | Total commercial
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for Loan Losses			10,284
Allowance for Unfunded Commitments			127
Commercial and business lending | Total commercial
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for Loan Losses			101,417
Allowance for Unfunded Commitments			12,403
Commercial real estate — investor | Total commercial
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for Loan Losses			40,514
Allowance for Unfunded Commitments			530
Real Estate Construction | Total commercial
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for Loan Losses			24,915
Allowance for Unfunded Commitments			7,532
Commercial Real Estate | Total commercial
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for Loan Losses			65,428
Allowance for Unfunded Commitments			8,062
Residential mortgage | Total consumer
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for Loan Losses			16,960
Allowance for Unfunded Commitments			0
Home Equity Loan | Total consumer
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for Loan Losses			10,926
Allowance for Unfunded Commitments			1,038
Other consumer | Total consumer
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for Loan Losses			6,639
Allowance for Unfunded Commitments			$ 405
Cumulative Effect, Period Of Adoption, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for Loan Losses		$ 131,147
Cumulative Effect, Period Of Adoption, Adjustment | Total commercial
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for Loan Losses		75,171
Cumulative Effect, Period Of Adoption, Adjustment | Total consumer
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for Loan Losses		55,975
Cumulative Effect, Period Of Adoption, Adjustment | Commercial and industrial | Total commercial
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for Loan Losses		48,921
Cumulative Effect, Period Of Adoption, Adjustment | Commercial real estate — owner occupied | Total commercial
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for Loan Losses		(1,851)
Cumulative Effect, Period Of Adoption, Adjustment | Commercial and business lending | Total commercial
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for Loan Losses		47,070
Cumulative Effect, Period Of Adoption, Adjustment | Commercial real estate — investor | Total commercial
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for Loan Losses		2,287
Cumulative Effect, Period Of Adoption, Adjustment | Real Estate Construction | Total commercial
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for Loan Losses		25,814
Cumulative Effect, Period Of Adoption, Adjustment | Commercial Real Estate | Total commercial
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for Loan Losses		28,101
Cumulative Effect, Period Of Adoption, Adjustment | Residential mortgage | Total consumer
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for Loan Losses		33,215
Cumulative Effect, Period Of Adoption, Adjustment | Home Equity Loan | Total consumer
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for Loan Losses		14,240
Cumulative Effect, Period Of Adoption, Adjustment | Other consumer | Total consumer
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for Loan Losses		8,520
Cumulative Effect, Period Of Adoption, Adjusted Balance
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for Loan Losses		354,425
Allowance for Unfunded Commitments		40,597
Cumulative Effect, Period Of Adoption, Adjusted Balance | Total commercial
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for Loan Losses		262,482
Cumulative Effect, Period Of Adoption, Adjusted Balance | Total consumer
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for Loan Losses		91,943
Cumulative Effect, Period Of Adoption, Adjusted Balance | Commercial and industrial | Total commercial
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for Loan Losses		152,330
Cumulative Effect, Period Of Adoption, Adjusted Balance | Commercial real estate — owner occupied | Total commercial
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for Loan Losses		8,560
Cumulative Effect, Period Of Adoption, Adjusted Balance | Commercial and business lending | Total commercial
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for Loan Losses		160,890
Cumulative Effect, Period Of Adoption, Adjusted Balance | Commercial real estate — investor | Total commercial
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for Loan Losses		43,331
Cumulative Effect, Period Of Adoption, Adjusted Balance | Real Estate Construction | Total commercial
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for Loan Losses		58,261
Cumulative Effect, Period Of Adoption, Adjusted Balance | Commercial Real Estate | Total commercial
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for Loan Losses		101,591
Cumulative Effect, Period Of Adoption, Adjusted Balance | Residential mortgage | Total consumer
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for Loan Losses		50,175
Cumulative Effect, Period Of Adoption, Adjusted Balance | Home Equity Loan | Total consumer
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for Loan Losses		26,204
Cumulative Effect, Period Of Adoption, Adjusted Balance | Other consumer | Total consumer
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for Loan Losses		$ 15,564