Income Taxes - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	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	$ 15,264	$ 12,350	$ 38,214	$ 37,215
Effective tax rate (as a percent)	38.00%	38.00%	36.00%	42.00%
Increase (decrease) in deferred tax assets, changes in unrealized gain (loss) on marketable securities			60	126
Increase (decrease) in deferred tax assets, changes in foreign currency translation adjustments			1,737	184
Unrecognized tax benefits	802		802
Unrecognized tax benefits that would affect the effective tax rate	574		574
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Amount of Unrecorded Benefit	802		802
Income tax penalties and interest expense	125		171
Income tax penalties and interest accrued	$ 310		$ 310