Stock-Based Compensation - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2015 USD ($) performance_metric $ / shares shares	Dec. 31, 2014 USD ($) $ / shares shares	Dec. 31, 2013 USD ($) $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock available for issuance (in shares) | shares	322,986
Common stock reserved for issuance (in shares) | shares	1,800,000
Weighted-average remaining contractual term, stock options outstanding	2 years 10 months 24 days	3 years 10 months 24 days
Weighted-average remaining contractual term, stock options vested and exercisable	2 years 10 months 24 days
Aggregate intrinsic value, stock options outstanding	$ 0
Aggregate intrinsic value, stock options vested and exercisable	15,500,000
Grant-date fair value, stock options vested	0	$ 400,000	$ 200,000
Intrinsic value, stock options exercised	700,000	4,200,000	5,100,000
Cash received from stock option exercises	116,000	$ 753,000	$ 570,000
Restricted stock units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant-date intrinsic value	$ 15,900,000
Weighted-average grant-date fair value (in $ per share) | $ / shares	$ 134.37	$ 183.83	$ 188.36
Fair value of awards vested	$ 11,800,000	$ 21,100,000	$ 17,900,000
Share settlement under RSUs (in shares) | shares	37,488	50,952	38,222
Cash used for employee withholding tax payments	$ 5,100,000	$ 9,100,000	$ 7,500,000
Unamortized stock-based compensation expense	$ 16,700,000	$ 12,600,000
Weighted average remaining amortization period	1 year 8 months 12 days	1 year 1 month 6 days
Restricted stock units (RSUs), performance-based [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards granted (in shares) | shares	33,632	30,101
Number of performance metrics | performance_metric	2
Measurement period for growth in operating income	1 year
Measurement period for total shareholder return	3 years
Stock-based compensation expense	$ 2,500,000	$ 1,400,000
Unamortized stock-based compensation expense	$ 6,200,000	$ 3,500,000
Compensation expense recognition period	3 years
Stock options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Contractual life in years	10 years
Vesting period of stock options in years	3 years
Unvested stock options (in shares) | shares	0
Minimum [Member] | Restricted stock units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Contractual life in years	1 year
Maximum [Member] | Restricted stock units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Contractual life in years	3 years