Share-Based Compensation - Additional Information (Detail) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2016 USD ($) period $ / shares shares	Dec. 31, 2015 USD ($) shares	Dec. 31, 2014 USD ($) shares	Apr. 21, 2016 shares	Apr. 23, 2015 shares	Jan. 31, 2013 shares	Oct. 31, 2009 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate intrinsic value of options exercised under stock option plans | $	$ 273.3	$ 196.5	$ 146.2
Cash received from option exercises and employee stock purchase plans | $	$ 580.9	361.1	283.6
Number of options vested and expected to vest | shares	3,000,000
Weighted average remaining contractual life of shares vested and expected to vest, years	5 years 10 months 20 days
Aggregate intrinsic value of shares vested and expected to vest | $	$ 587.5
Options vested and expected to vest, weighted-average exercise price per share | $ / shares	$ 442.48
Excess tax benefit from employee stock plans | $	$ 44.1	34.3	24.0
Share-based compensation charges, income tax effect | $	56.1	51.8	53.5
Employee Service Share-based Compensation, Tax Benefit Realized from Exercise of Stock Options | $	$ 82.9
2010 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation, options, expiration term (in years)	10 years
Number of shares of common stock reserved for issuance (shares) | shares				7,050,000	6,250,000
Shares were reserved for future issuance (shares) | shares	1,700,000
2009 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation, options, expiration term (in years)	10 years
Number of shares of common stock reserved for issuance (shares) | shares					1,455,000	1,155,000
Shares were reserved for future issuance (shares) | shares	100,000
2000 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation, options, expiration term (in years)	10 years
Minimum exercise price of NSOs, percentage of fair value	85.00%
2000 Non-Employee Directors' Stock Option Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation, options, expiration term (in years)	10 years
Number of shares of common stock reserved for issuance (shares) | shares							150,000
Shares were reserved for future issuance (shares) | shares	48,000
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation expense | $	$ 200.3
Weighted average period unrecognized compensation expenses are expected to be recognized, years	2 years 7 months 6 days
Expected to vest (in shares) | shares	500,000
Aggregate intrinsic value | $	$ 336.2
Canceled (shares) | shares	35,000
Vested in period, aggregate fair value | $	$ 65.3	$ 29.5	$ 0.0
Restricted Stock Units (RSUs) | 2010 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares were reserved for future issuance (shares) | shares	800,000
Restricted Stock Units (RSUs) | Employees
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage	25.00%
Share based vesting period	4 years
Restricted Stock Units (RSUs) | Director
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based vesting period	1 year
Annual Grant Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage vesting upon six months of service	12.50%
Percentage vesting per month after six months of service	2.0833%
Annual Grant Options | 2000 Non-Employee Directors' Stock Option Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based vesting period	1 year
New Hire Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage vesting upon one year of service	25.00%
Percentage vesting per month after one year	2.0833%
Initial Grant Options | 2000 Non-Employee Directors' Stock Option Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage vesting upon one year of service		33.3333%
Percentage vesting per month after one year		2.7778%
Stock options granted initial vesting period, years		3 years
Employee Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares were reserved for future issuance (shares) | shares	100,000
Minimum hours employed per week	20 hours
Minimum months employed per year	5 months
Maximum percentage of employees on stockholders to participate in ESPP	5.00%
Percentage of employee payroll deduction under the stock plan, maximum	15.00%
Duration for each offering period	24 months
Number of shorter purchase periods that each offering period is divided into | period	4
Duration of each shorter offering period	6 months
Discount on fair market value on the offering date	85.00%
Discount on fair market value on the purchase date	85.00%
Period of look-back that could cause offering period to reset	2 years
Employee stock purchase plan, shares issued | shares	100,000	100,000	100,000
Employee stock purchase plan, value of shares issued | $	$ 32.5	$ 31.2	$ 29.4
Total unrecognized compensation expense | $	$ 9.0
Weighted average period unrecognized compensation expenses are expected to be recognized, years	1 year
Nonvested Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation expense | $	$ 80.3
Weighted average period unrecognized compensation expenses are expected to be recognized, years	2 years 2 months 12 days
Initial RSU grants | Director
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage		33.3333%
Share based vesting period		3 years
February Grant | Annual Grant Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage vesting upon six months of service	12.50%
Percentage vesting per month after six months of service	2.0833%
February Grant | Annual Grant Options | 2010 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based vesting period	4 years
August Grant | Annual Grant Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage vesting at the end of one month	14.5833%
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage	2.0833%
August Grant | Annual Grant Options | 2010 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based vesting period	3 years 6 months