Income Taxes (Additional Information) (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Provision for income taxes	$ 32,772,000	$ 29,889,000	$ 88,614,000	$ 89,332,000
Effective tax rate	29.20%	29.50%	29.20%	29.10%
Minimum
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Reasonably possible change in unrecognized tax benefits over next 12 months	$ 0		$ 0
Maximum
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Reasonably possible change in unrecognized tax benefits over next 12 months	$ 2,200,000		$ 2,200,000