Share-Based Compensation - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Expected volatility term	5 years
Closing stock price	$ 104.86
Number of shares available for issuance	1,749,744
Equity Incentive Plan
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Maximum aggregate number of shares that may be awarded and sold	7,543,321
Number of shares available for Grant additional shares approved in period	2,000,000
Options granted under the 2006 Incentive Plan, expiration period	7 years
Options, exercisable period	4 years
Equity Incentive Plan | Restricted stock units | Lower Limit
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Vesting period	3 years
Equity Incentive Plan | Performance-based restricted stock | Lower Limit
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Vesting period	12 months
Employee Stock Purchase Plan
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Maximum percentage of gross compensation that participating employees may annually contribute towards ESPP	10.00%
Maximum amount that participating employees may annually contribute towards ESPP	$ 25,000
Percentage of fair market value of common stock at which employees may purchase shares under ESPP	85.00%
Number of shares issued under ESPP	176,416
Proceeds from issuance of shares under ESPP	$ 9,800,000
Number of shares available for issuance	696,309