Income Taxes - Additional Information (Detail) (USD $)	3 Months Ended	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Schedule Of Pre Tax Income [Line Items]
Pre-tax income from U.S. operations		$ 112,500,000	$ 105,200,000	$ 84,700,000
U.S. federal tax at statutory rate		35.00%	35.00%	35.00%
Stock compensation expense		7,266,000	6,022,000
Employee and non-employee awards		52,600,000
Additional annual limitations		50% or greater change
Percentage of change in ownership		50.00%
Additional annual limitations period		3 years
Capital loss on the sale		20,600,000
Capital loss carried back		1,200,000
Reduction in income tax provision	6,700,000
Decrease in unrecognized tax benefit reserve	3,600,000
Increase unrecognized tax benefits	3,100,000			3,100,000
Undistributed earnings of foreign subsidiaries		5,300,000
Undistributed earnings of foreign subsidiaries, deferred tax liability		500,000
Foreign Country [Member]
Schedule Of Pre Tax Income [Line Items]
Pre-tax income from foreign operations		6,000,000	2,100,000	4,600,000
US Country [Member]
Schedule Of Pre Tax Income [Line Items]
Net operating loss carryforwards		$ 8,000,000
Net operating loss carryforwards, expiration date		2021