Income Taxes (Detail) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Provision for income taxes	$ 15,889,000	$ 18,955,000
Effective income tax rate	35.90%	33.40%
Unrecognized tax benefits	21,700,000		20,600,000
Unrecognized tax benefits reductions resulting from settlements with taxing authorities and lapse of applicable statute of limitations	$ 4,600,000