Stock Compensation (Summary Of Stock Options Activity) (Details) - Stock Options [Member] - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Options, Outstanding		341,852	380,773	454,573
Number of Options, Granted		16,000	16,000	24,000
Number of Options, Exercised		(99,178)	(61,273)	(97,800)
Number of Options, Forfeited			(4,000)
Number of options, Special dividend adjustment	[1]		10,352
Number of Options, Outstanding		258,674	341,852	380,773
Number of Options, Exercisable at December 31, 2015		194,999
Weighted Average Exercise Price, Outstanding		$ 57.11	$ 56.45	$ 53.41
Weighted Average Exercise Price, Granted		80.13	82.84	78.99
Weighted Average Exercise Price, Exercised		51.31	49.84	47.87
Weighted Average Exercise Price, Forfeited			52.35
Weighted Average Exercise Price, Outstanding		60.76	$ 57.11	$ 56.45
Weighted Average Exercise Price, Exercisable at December 31, 2015		$ 56.23
Weighted Average Remaining Contract Life, Outstanding at December 31, 2015		5 years 4 days
Weighted Average Remaining Contract Life, Exercisable at December 31, 2015		4 years 1 month 21 days
Aggregate Intrinsic Value, Outstanding at December 31, 2015		$ 6,899
Aggregate Intrinsic Value, Exercisable at December 31, 2015		$ 6,084

[1] In accordance with the applicable equity award plan documents, the number and exercise price of outstanding options as of December 31, 2014 have been adjusted as a result of the Special Cash Dividend so that the option holder maintains their economic position with respect to the shareholders.