Basis Of Presentation (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Decrease income taxes	$ 18,835	$ 16,664	$ 15,153	$ 48,175
Increase to basic earnings per share	$ 2.22	$ 1.66	$ 2.72	$ 4.66
Increase to diluted earnings per share	$ 2.13	$ 1.62	$ 2.60	$ 4.54
ASU No. 2016-09 [Member]
Decrease income taxes	$ 1,800		$ 8,100
Effective tax rate	34.70%		25.80%
Increase to basic earnings per share	$ 0.11		$ 0.51
Increase to diluted earnings per share	$ 0.09		$ 0.46