Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2018

Stock-Based Compensation [Abstract]

Schedule of Assumptions Used to Estimate Fair Value of Stock Options

	For the nine months ended
	September 30,
	2018	2017
Risk free interest rate	2.57% - 2.87%	1.70% - 1.97%
Dividend yield	0.7%	0.0%
Expected volatility	22%	20%
Expected lives	4.6 years	4.6 years

Summary of Stock Option Activity

		Weighted-		Weighted-Average
		Average		Remaining
	Number	Exercise Price		Contractual	Aggregate
	of Shares	Per Share		Life (in years)	Intrinsic Value
Outstanding at December 31, 2017	4,842	$	100.12
Granted	937	$	156.54
Exercised	(548)	$	81.99
Forfeited/canceled	(38)	$	123.91
Outstanding at September 30, 2018	5,193	$	112.05	4.3	$	252,235
Exercisable at September 30, 2018	2,538	$	97.34	3.1	$	160,627
Unvested at September 30, 2018	2,655	$	126.11	5.4	$	91,608

Summary of Restricted Stock Unit Activity

		Weighted-Average
	Number of	Grant Date Fair
	Shares	Value per Share
	(in thousands)
Outstanding at December 31, 2017	328	$	110.20
Granted	137	$	156.61
Vested	(129)	$	110.94
Forfeited/canceled	(11)	$	134.37
Outstanding at September 30, 2018	325	$	128.73