Goodwill and Other Intangible Assets - Summary of Other Intangible Assets Net by Segment (Detail) - USD ($)
$ in Thousands
Dec. 31, 2015
Dec. 31, 2014
Finite-Lived Intangible Assets [Line Items]    
Net Carrying Amount $ 18,687 $ 20,939
Executive Search and Leadership Consulting [Member]    
Finite-Lived Intangible Assets [Line Items]    
Net Carrying Amount 3,521 1,427
Executive Search and Leadership Consulting [Member] | Americas [Member]    
Finite-Lived Intangible Assets [Line Items]    
Net Carrying Amount 764 1,044
Executive Search and Leadership Consulting [Member] | Europe [Member]    
Finite-Lived Intangible Assets [Line Items]    
Net Carrying Amount 2,548 0
Executive Search and Leadership Consulting [Member] | Asia Pacific [Member]    
Finite-Lived Intangible Assets [Line Items]    
Net Carrying Amount 209 383
Culture Shaping [Member]    
Finite-Lived Intangible Assets [Line Items]    
Net Carrying Amount $ 15,166 $ 19,512