Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2017

Stock-Based Compensation [Abstract]

Schedule Of Assumptions Used To Estimate Fair Value Of Stock Options

	For the nine months ended
	September 30,
	2017	2016
Risk free interest rate	1.70% - 1.97%	1.11% - 1.43%
Dividend yield	0.0%	0.0%
Expected volatility	20%	20%
Expected lives	4.6 years	4.7 years

Company's Activities With Respect To Its Stock Options

				Weighted-
		Weighted-		Average
		Average		Remaining
	Number	Exercise Price		Contractual	Aggregate
	of Shares	Per Share		Life (in years)	Intrinsic Value
Outstanding at December 31, 2016	4,447	$	93.09
Granted	1,171	$	115.41
Exercised	(615)	$	78.64
Canceled	(62)	$	105.44
Outstanding at September 30, 2017	4,941	$	100.03	4.6	$	217,485
Exercisable at September 30, 2017	2,076	$	87.74	3.3	$	116,910
Unvested at September 30, 2017	2,865	$	108.93	5.5	$	100,575

Company's Restricted Stock Unit Activity

		Weighted-
		Average
		Grant Date
	Number of	Fair Value per
	Shares	Share
	(in thousands)
Outstanding at December 31, 2016	291	$	101.74
Granted	171	$	116.52
Vested	(122)	$	98.75
Forfeited/canceled	(10)	$	109.83
Outstanding at September 30, 2017	330	$	110.27