Income Taxes (Detail) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Provision for income taxes	$ 26,216,000	$ 25,049,000	$ 45,171,000	$ 40,154,000
Effective income tax rate	33.10%	35.00%	33.20%	32.60%
Unrecognized tax benefits	17,400,000		17,400,000		14,500,000
Unrecognized tax benefits reductions resulting from settlements with taxing authorities and lapse of applicable statute of limitations			$ 4,000,000