XML 47 R32.htm IDEA: XBRL DOCUMENT v3.8.0.1
Summary of Significant Accounting Policies - Fixed Assets (Details)
12 Months Ended
Dec. 31, 2017
Furniture, Equipment and Technology and Software | Minimum  
Property, Plant and Equipment [Line Items]  
Fixed assets, useful life 3 years
Furniture, Equipment and Technology and Software | Maximum  
Property, Plant and Equipment [Line Items]  
Fixed assets, useful life 10 years
Internal-Use Software Development | Minimum  
Property, Plant and Equipment [Line Items]  
Fixed assets, useful life 3 years
Internal-Use Software Development | Maximum  
Property, Plant and Equipment [Line Items]  
Fixed assets, useful life 10 years