Employee Stock And Incentive Plan (Assumptions Used In The Pricing Model) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (years)	5 years 5 months 19 days	5 years 5 months 15 days	5 years 5 months 12 days
Risk-free interest rate	2.53%	2.72%	2.01%
Expected volatility	17.70%	17.20%	17.70%
Dividend yield	2.44%	2.37%	2.51%
Grant date fair value	$ 5.25	$ 5.10	$ 4.07
Performance Share Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (years)		3 years	3 years
Risk-free interest rate		2.43%	1.49%
Expected volatility		17.20%	17.90%
Grant date fair value		$ 37.42	$ 30.79
Intrinsic value of vested PSUs	$ 3,181	$ 4,704	$ 3,926
Fair value of vested PSUs	$ 2,569	$ 3,613	$ 3,207