Stock-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2017

Stock-Based Compensation [Abstract]

Schedule Of Assumptions Used To Estimate Fair Value Of Stock Options

	For the three months ended
	March 31,
	2017	2016
Risk free interest rate	1.91%	1.33% - 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	1,149	$	115.17
Exercised	(213)	$	62.99
Canceled	(20)	$	102.89
Outstanding at March 31, 2017	5,363	$	98.98	5.0	$	118,838
Exercisable at March 31, 2017	2,451	$	87.48	3.8	$	82,673
Unvested at March 31, 2017	2,912	$	108.66	6.0	$	36,165

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	161	$	115.17
Vested	(115)	$	98.50
Forfeited/canceled	(2)	$	105.21
Outstanding at March 31, 2017	335	$	109.29