Loans and Allowance for Credit Losses Past Due Loan Status and Non-Accrual Loans by Portfolio Segment (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Financing Receivable, Past Due [Line Items]
≥ 90 Days Past Due and Accruing	$ 13,761	$ 16,057
Non- accrual	128,321	125,098
Current	18,845,238	16,620,575
Net Loans	19,028,621	16,837,526
Financial Asset, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due and Non-accrual	33,743	56,326
Financial Asset, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due and Non-accrual	7,558	19,470
Real estate - commercial mortgage
Financing Receivable, Past Due [Line Items]
≥ 90 Days Past Due and Accruing	2,499	4,113
Non- accrual	40,926	33,166
Current	6,987,336	6,651,042
Net Loans	7,046,330	6,700,776
Real estate - commercial mortgage \| Financial Asset, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due and Non-accrual	11,867	10,912
Real estate - commercial mortgage \| Financial Asset, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due and Non-accrual	3,702	1,543
Commercial and industrial
Financing Receivable, Past Due [Line Items]
≥ 90 Days Past Due and Accruing	1,950	1,385
Non- accrual	35,274	48,106
Current	5,924,376	4,392,278
Net Loans	5,968,154	4,446,701
Commercial and industrial \| Financial Asset, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due and Non-accrual	5,326	2,302
Commercial and industrial \| Financial Asset, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due and Non-accrual	1,228	2,630
Real-estate - home equity
Financing Receivable, Past Due [Line Items]
≥ 90 Days Past Due and Accruing	3,070	3,564
Non- accrual	8,682	7,004
Current	1,206,089	1,292,035
Net Loans	1,222,709	1,314,944
Real-estate - home equity \| Financial Asset, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due and Non-accrual	3,966	9,635
Real-estate - home equity \| Financial Asset, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due and Non-accrual	902	2,706
Real estate - residential mortgage
Financing Receivable, Past Due [Line Items]
≥ 90 Days Past Due and Accruing	3,394	5,735
Non- accrual	24,893	16,676
Current	3,021,682	2,584,763
Net Loans	3,061,835	2,641,465
Real estate - residential mortgage \| Financial Asset, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due and Non-accrual	10,686	26,982
Real estate - residential mortgage \| Financial Asset, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due and Non-accrual	1,180	7,309
Real-estate - construction
Financing Receivable, Past Due [Line Items]
≥ 90 Days Past Due and Accruing	2,430	688
Non- accrual	1,621	3,618
Current	1,003,483	964,158
Net Loans	1,007,534	971,079
Real-estate - construction \| Financial Asset, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due and Non-accrual	0	1,715
Real-estate - construction \| Financial Asset, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due and Non-accrual	0	900
Consumer
Financing Receivable, Past Due [Line Items]
≥ 90 Days Past Due and Accruing	306	458
Non- accrual	235	0
Current	466,926	457,556
Net Loans	469,551	463,164
Consumer \| Financial Asset, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due and Non-accrual	1,648	4,228
Consumer \| Financial Asset, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due and Non-accrual	436	922
Equipment lease financing, other and overdrafts
Financing Receivable, Past Due [Line Items]
≥ 90 Days Past Due and Accruing	112	114
Non- accrual	16,690	16,528
Current	235,346	278,743
Net Loans	252,508	299,397
Equipment lease financing, other and overdrafts \| Financial Asset, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due and Non-accrual	250	552
Equipment lease financing, other and overdrafts \| Financial Asset, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due and Non-accrual	$ 110	$ 3,460

Amount of financing receivable 90 days or more past due and still accruing.

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