Income Taxes (Additional Information) (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Provision for income taxes	$ 28,913,000	$ 29,769,000	$ 55,842,000	$ 59,443,000
Effective tax rate	29.40%	29.30%	29.20%	28.90%
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