Quarterly report pursuant to Section 13 or 15(d)

Income Taxes - Additional Information (Detail)

v3.10.0.1
Income Taxes - Additional Information (Detail) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended 12 Months Ended
Mar. 31, 2018
Jun. 30, 2018
Dec. 31, 2017
Jun. 30, 2017
Dec. 31, 2016
Schedule Of Income Taxes [Line Items]          
U.S. federal and state statutory rate   26.00%      
Provisional tax $ 91,900   $ 99,900    
Reduction in provisional tax   $ 8,000      
Cash and cash equivalents   844,847 $ 736,431 $ 751,581 $ 718,536
Non-US [Member]          
Schedule Of Income Taxes [Line Items]          
Cash and cash equivalents   $ 375,900      
Non-US [Member] | Geographic concentration risk [Member] | Cash and Cash Equivalents Geographical Area [Member]          
Schedule Of Income Taxes [Line Items]          
Percentage of cash and cash equivalents   44.50%      
Non-US [Member] | Funds Available For Repatriation [Member]          
Schedule Of Income Taxes [Line Items]          
Cash and cash equivalents   $ 176,900      
ASU 2016-09 [Member]          
Schedule Of Income Taxes [Line Items]          
Excess tax benefits recorded in earnings   $ 1,600      
Minimum [Member]          
Schedule Of Income Taxes [Line Items]          
Effective tax rate, remainder of fiscal year   12.00%      
Minimum [Member] | Non-U.S jurisdictions [Member]          
Schedule Of Income Taxes [Line Items]          
Statutory federal rate   0.00%      
Maximum [Member]          
Schedule Of Income Taxes [Line Items]          
Effective tax rate, remainder of fiscal year   17.00%      
Maximum [Member] | Non-U.S jurisdictions [Member]          
Schedule Of Income Taxes [Line Items]          
Statutory federal rate   34.00%