Employee Stock And Incentive Plan (Summary Of Value Of Restricted Stock Units) (Details) - Restricted Stock Units [Member] - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average fair value of stock awards granted	$ 36.25	$ 35.15	$ 30.37
Intrinsic value of vested RSUs	$ 1,456	$ 1,605	$ 896
Fair value of vested RSUs	$ 1,341	$ 1,268	$ 751

The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(1)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

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