Income Taxes (Detail) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Provision for income taxes	$ 18,955,000	$ 15,105,000
Effective income tax rate	33.40%	29.20%
Unrecognized tax benefits	15,800,000		14,500,000
Unrecognized tax benefits reductions resulting from settlements with taxing authorities and lapse of applicable statute of limitations	$ 4,000,000