Principles Of Consolidation And Presentation (Narrative) (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Mar. 31, 2020	Jan. 01, 2020	Dec. 31, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	$ 3,358,169	$ 3,252,464		$ 3,138,472	$ 3,171,363	$ 3,043,213	$ 2,937,149
Financing Receivable, Allowance for Credit Loss	240,744	171,653	$ 139,643
Off-Balance Sheet, Credit Loss, Liability	35,299	32,250	17,165	1,075
Commercial Portfolio Segment [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing Receivable, Allowance for Credit Loss	130,553	83,551	62,049
Off-Balance Sheet, Credit Loss, Liability	34,052	31,061	16,456
Personal Banking Portfolio Segment [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing Receivable, Allowance for Credit Loss	110,191	88,102	77,594
Off-Balance Sheet, Credit Loss, Liability	1,247	1,189	709
Retained Earnings [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	$ 232,082	$ 224,643	3,800	$ 201,562	$ 384,232	$ 307,193	$ 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