Income Taxes (Additional Information) (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Income Tax Disclosure [Abstract]
Provision for income taxes	$ 29,889,000	$ 22,812,000	$ 89,332,000	$ 72,774,000
Effective tax rate	29.50%	26.30%	29.10%	27.90%
Reasonably possible change in unrecognized tax benefits over next 12 months, lower range	0		0
Reasonably possible change in unrecognized tax benefits over next 12 months, upper range	$ 1,000,000		$ 1,000,000