Loans And Allowance For Credit Losses (Credit Quality Commercial Loan Portfolio Non-Vintage) (Details) - Commercial Portfolio Segment [Member] $ in Thousands	Dec. 31, 2019 USD ($)
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial Loan Portfolio Gross Carrying Amount	$ 9,298,380
Pass [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial Loan Portfolio Gross Carrying Amount	8,910,119
Special Mention [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial Loan Portfolio Gross Carrying Amount	215,256
Substandard [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial Loan Portfolio Gross Carrying Amount	164,484
Non-Accrual [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial Loan Portfolio Gross Carrying Amount	8,521
Business [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial Loan Portfolio Gross Carrying Amount	5,565,449
Business [Member] | Pass [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial Loan Portfolio Gross Carrying Amount	5,393,928
Business [Member] | Special Mention [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial Loan Portfolio Gross Carrying Amount	80,089
Business [Member] | Substandard [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial Loan Portfolio Gross Carrying Amount	83,943
Business [Member] | Non-Accrual [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial Loan Portfolio Gross Carrying Amount	7,489
Real Estate - Construction And Land [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial Loan Portfolio Gross Carrying Amount	899,377
Real Estate - Construction And Land [Member] | Pass [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial Loan Portfolio Gross Carrying Amount	856,364
Real Estate - Construction And Land [Member] | Special Mention [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial Loan Portfolio Gross Carrying Amount	42,541
Real Estate - Construction And Land [Member] | Substandard [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial Loan Portfolio Gross Carrying Amount	470
Real Estate - Construction And Land [Member] | Non-Accrual [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial Loan Portfolio Gross Carrying Amount	2
Real Estate - Business [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial Loan Portfolio Gross Carrying Amount	2,833,554
Real Estate - Business [Member] | Pass [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial Loan Portfolio Gross Carrying Amount	2,659,827
Real Estate - Business [Member] | Special Mention [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial Loan Portfolio Gross Carrying Amount	92,626
Real Estate - Business [Member] | Substandard [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial Loan Portfolio Gross Carrying Amount	80,071
Real Estate - Business [Member] | Non-Accrual [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial Loan Portfolio Gross Carrying Amount	$ 1,030