Share-Based Compensation (Schedule Of Stock Option Activity) (Details) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($) $ / shares shares
Share-Based Compensation [Abstract]
Outstanding, at beginning of year | shares	3,176
Granted | shares	384
Exercised | shares	(716)
Forfeited | shares	(117)
Outstanding, at end of year | shares	2,727
Fully vested, at end of year | shares	1,327
Fully vested and expected to vest, at end of year | shares	2,649
Weighted average exercise price of beginning balance of options outstanding | $ / shares	$ 57.31
Weighted average exercise price of options granted | $ / shares	142.89
Weighted average exercise price of options exercised | $ / shares	42.66
Weighted average exercise price of options forfeited | $ / shares	68.41
Weighted average exercise price of ending balance of options outstanding | $ / shares	72.72
Weighted average exercise price of options fully vested | $ / shares	56.06
Weighted average exercise price of options fully vested and expected to vest | $ / shares	$ 72.45
Weighted average remaining contractual term of ending balance of options outstanding	6 years
Weighted average remaining contractual term of options fully vested	4 years 2 months 12 days
Weighted average remaining contractual term of options fully vested and expected to vest	5 years 10 months 24 days
Aggregate Intrinsic Value | $	$ 228,243
Aggregate intrinsic value of options fully vested | $	133,115
Aggregate intrinsic value of options expected to vest | $	$ 222,422