Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Income Tax Disclosure [Abstract]
Provision for Income Taxes	$ 16,723	$ 15,387	$ 22,935	$ 22,950
Effective Income Tax Rate Reconciliation, Percent	51.00%	34.00%	51.00%	35.00%
Increase (decrease) in deferred tax assets, changes in unrealized gain (loss) on marketable securities			$ 461	$ (552)
Increase (decrease) in deferred tax assets, changes in foreign currency translation adjustments			$ 1,220	$ (1,453)