Stockholders' Equity - Additional Information (Detail) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($) purchase_period $ / shares shares	Dec. 31, 2018 USD ($) $ / shares shares	Dec. 31, 2017 USD ($) $ / shares shares	May 16, 2013 shares
Stockholders Equity Note [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	8,187
Preferred stock, par value (usd per share) | $ / shares	$ 0.0001	$ 0.0001
Total intrinsic value of stock options exercised | $	$ 2,000	$ 17,600	$ 18,100
Payroll taxes paid upon the vesting of equity awards | $	$ (57,675)	$ (86,067)	$ (46,168)
Employee Stock Purchase Plan, Duration Of Offering Period	24 months
Number of offering periods | purchase_period	4
Number of shares issued (in thousands)	130,000	164,000	202,000
Stock-based compensation expense | $	$ 88,184	$ 70,763	$ 58,854
Exercised (usd per share) | $ / shares	$ 8.07
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	0
Incentive Plan 2005
Stockholders Equity Note [Line Items]
Common Stock Capital Shares Reserved For Future Issuance Shares Available	5,450,162
2010 Purchase Plan
Stockholders Equity Note [Line Items]
Employee stock purchase plan, purchase price as percentage of fair market value of common stock	85.00%
Restricted Stock Units (RSUs)
Stockholders Equity Note [Line Items]
Vested rand released in period, Total intrinsic value | $	$ 112,400	146,700	99,500
Vested in period, Fair value | $	$ 46,800	$ 42,200	$ 46,200
Granted (usd per share) | $ / shares	$ 255.42	$ 262.58	$ 118.77
Total unamortized compensation cost | $	$ 88,700
Weighted average period of total unamortized cost	2 years
Restricted stock units, shares vested and released (shares)	442,524
Restricted stock units, shares withheld for tax payments	141,543
Restricted stock units, net issuance	300,981
Market Performance Based Restricted Stock Units
Stockholders Equity Note [Line Items]
Vested rand released in period, Total intrinsic value | $	$ 47,700	$ 92,700	$ 28,800
Vested in period, Fair value | $	$ 14,800	19,500	15,000
Granted (usd per share) | $ / shares	$ 240.73
Total unamortized compensation cost | $	$ 36,200
Weighted average period of total unamortized cost	1 year 1 month 6 days
Restricted stock units, shares vested and released (shares)	191,176
Restricted stock units, shares withheld for tax payments	88,292
Restricted stock units, net issuance	102,884
Market Performance Based Restricted Stock Units | Minimum
Stockholders Equity Note [Line Items]
Percentage of market-performance based restricted stock units eligible to vest over the vesting period	250.00%
Market Performance Based Restricted Stock Units | Maximum
Stockholders Equity Note [Line Items]
Stock incentive plan, vesting period	3 years
2010 Purchase Plan
Stockholders Equity Note [Line Items]
Share Based Compensation Arrangement By Share Based Payment Award Shares Remaining Available For Issuance	416,293
Employee Stock Incentive Plan 2005
Stockholders Equity Note [Line Items]
Number of shares available for grant (shares)				27,783,379
Share-based Compensation Arrangement by Share-based Payment Award, Weight Of Awarded Shares Against Authorized Maximum	1.9			1.9
2010 Purchase Plan | Maximum
Stockholders Equity Note [Line Items]
Maximum number of shares available	2,400,000
Employee Stock Purchase Plan
Stockholders Equity Note [Line Items]
Total unamortized compensation cost | $	$ 9,900
Weighted average period of total unamortized cost	10 months 24 days
Stock-based compensation expense | $	$ 12,100	$ 5,600	$ 5,400