XML 93 R73.htm IDEA: XBRL DOCUMENT v3.6.0.2
Business Information - Additional Information (Detail)
$ in Millions
12 Months Ended
Dec. 31, 2016
USD ($)
Segment
Entity
Dec. 31, 2015
USD ($)
Entity
Dec. 31, 2014
Segment Reporting Information [Line Items]      
Number of business segments (segment) | Segment 1    
Advisory revenues as a percentage of total revenue 100.00% 100.00% 102.00%
United States      
Segment Reporting Information [Line Items]      
Long-lived assets | $ $ 34.8 $ 43.0  
Advisory Services      
Segment Reporting Information [Line Items]      
Number of clients that accounted for more than 10% of total revenues | Entity 0 0  
Revenue      
Segment Reporting Information [Line Items]      
Principal investments in merchant banking funds, percent of revenue 1.00%    
Revenue | Geographic Concentration Risk | United States      
Segment Reporting Information [Line Items]      
Percent of revenue per derived location 59.00% 66.00% 58.00%
Revenue | Geographic Concentration Risk | United Kingdom      
Segment Reporting Information [Line Items]      
Percent of revenue per derived location 27.00% 20.00% 25.00%