Stock-Based Awards and Other Equity Instruments (Tables)

12 Months Ended

Dec. 31, 2016

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Summary of Stock Option Activity

The following table presents a summary of our stock option activity:

	Options		Weighted Average Exercise Price		Remaining Contractual Life	Aggregate Intrinsic Value
	(In thousands)				(In years)	(In thousands)
Balance as of January 1, 2014	15,427		$	36.03
Granted	4,113		78.70
Exercised	(3,804	)	25.66
Cancelled	(1,301	)	53.69
Balance as of December 31, 2014	14,435		49.33
Granted	7,572		94.13
Exercised	(4,201	)	34.57
Cancelled	(751	)	74.06
Balance as of December 31, 2015	17,055		71.77
Granted	5,670		105.37
Exercised	(2,686	)	47.57
Cancelled	(1,198	)	91.62
Balance as of December 31, 2016	18,841		84.07		4.7	$	552,445
Exercisable as of December 31, 2016	5,770		58.27		3.1	317,909
Vested and expected to vest after December 31, 2016(1)	18,841		84.07		4.7	552,445

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(1) As of our adoption of the new share-based payment accounting standard in 2016, we no longer include a forfeiture rate in our vested and expected to vest calculation unless necessary for a performance condition award.

Weighted Average Assumptions of Black-Scholes and Monte Carlo Option-Pricing Models

The fair value of stock options granted during the years ended December 31, 2016, 2015 and 2014 were estimated at the date of grant using appropriate valuation techniques, including the Black-Scholes and Monte Carlo option-pricing models, assuming the following weighted average assumptions:

	2016			2015			2014
Risk-free interest rate	0.97		%	1.19		%	1.13		%
Expected volatility	39.06		%	41.48		%	42.97		%
Expected life (in years)	3.59			4.06			4.04
Dividend yield	0.91		%	0.78		%	0.76		%
Weighted-average estimated fair value of options granted during the year	$	29.48		$	30.56		$	25.80

Summary of Restricted Stock Units Activity

The following table presents a summary of RSU activity:

	RSUs		Weighted Average Grant-Date Fair Value
	(In thousands)
Balance as of January 1, 2014	432		$	50.64
Granted	108		80.94
Vested	(159	)	45.90
Cancelled	(44	)	55.52
Balance as of December 31, 2014	337		61.97
Granted	1,643		123.42
Vested	(493	)	103.73
Cancelled	(91	)	67.11
Balance as of December 31, 2015	1,396		119.20
Granted	691		109.38
Vested	(516	)	118.71
Cancelled	(222	)	117.84
Balance as of December 31, 2016	1,349		114.58