Share-Based Compensation (Schedule Of Restricted Stock Unit Activity) (Details) shares in Thousands	12 Months Ended
	Dec. 31, 2018 $ / shares shares
Restricted stock units (RSU's)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Nonvested, at beginning of year (in shares) | shares	383
Granted (in shares) | shares	79
Vested (in shares) | shares	(136)
Forfeited (in shares) | shares	(20)
Nonvested, at end of year (in shares) | shares	306
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Weighted average grant date fair value, beginning of year (in USD per share) | $ / shares	$ 85.74
Weighted average grant date fair value, granted (in USD per share) | $ / shares	179.22
Weighted average grant date fair value, vested (in USD per share) | $ / shares	74.69
Weighted average grant date fair value, forfeited (in USD per share) | $ / shares	100.02
Weighted average grant date fair value, end of year (in USD per share) | $ / shares	$ 113.87
Restricted stock units expected to vest reduced for estimated forfeitures
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Nonvested, at end of year (in shares) | shares	289
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Weighted average grant date fair value, end of year (in USD per share) | $ / shares	$ 113.44