Principles Of Consolidation And Presentation (Narrative) (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Jun. 30, 2020	Jan. 01, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Dec. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	$ 3,306,264	$ 3,358,169		$ 3,138,472	$ 3,106,014	$ 3,171,363	$ 2,937,149
Financing Receivable, Allowance for Credit Loss	236,360	240,744	$ 139,643
Off-Balance Sheet, Credit Loss, Liability	35,200	35,299	17,165	1,075
Commercial Portfolio Segment [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing Receivable, Allowance for Credit Loss	128,424	130,553	62,049
Off-Balance Sheet, Credit Loss, Liability	33,992	34,052	16,456
Personal Banking Portfolio Segment [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing Receivable, Allowance for Credit Loss	107,936	110,191	77,594
Off-Balance Sheet, Credit Loss, Liability	1,208	1,247	709
Retained Earnings [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	$ 326,890	$ 232,082		$ 201,562	$ 463,231	$ 384,232	$ 241,163
Accounting Standards Update 2016-13
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing Receivable, Allowance for Credit Loss			(21,039)
Off-Balance Sheet, Credit Loss, Liability			16,090
Deferred Income Tax Assets, Net			(1,200)
Accounting Standards Update 2016-13 | Commercial Portfolio Segment [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing Receivable, Allowance for Credit Loss			(29,711)
Accounting Standards Update 2016-13 | Personal Banking Portfolio Segment [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing Receivable, Allowance for Credit Loss			8,672
Accounting Standards Update 2016-13 | Retained Earnings [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest			$ 3,800