XML 115 R98.htm IDEA: XBRL DOCUMENT v3.10.0.1
Income Taxes - Schedule of Changes in Balance of Gross Unrecognized Tax Benefits (Detail)
$ in Thousands
 6 Months Ended
Jun. 30, 2018
USD ($)
Income Tax Contingency [Line Items]  
Accrued in connection with the ETFS acquisition $ 30,466
Increases 37
Foreign currency translation (2,164)
Ending balance 28,339
Unrecognized Tax Benefits [Member]  
Income Tax Contingency [Line Items]  
Accrued in connection with the ETFS acquisition 25,631
Foreign currency translation (1,820)
Ending balance 23,811
Interest and Penalties [Member]  
Income Tax Contingency [Line Items]  
Accrued in connection with the ETFS acquisition 4,835
Increases 37
Foreign currency translation (344)
Ending balance $ 4,528