Goodwill and Other Intangible Assets - Goodwill - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Culture Shaping [Member]
Goodwill And Other Intangible Assets [Line Items]
Percentage of fair value excess by carrying value	5.00%
Co Company [Member]
Goodwill And Other Intangible Assets [Line Items]
Goodwill acquired		$ 10,745
Executive Search and Leadership Consulting [Member] | Europe [Member]
Goodwill And Other Intangible Assets [Line Items]
Percentage of fair value excess by carrying value	68.00%
Executive Search and Leadership Consulting [Member] | Americas [Member]
Goodwill And Other Intangible Assets [Line Items]
Percentage of fair value excess by carrying value	118.00%
Executive Search and Leadership Consulting [Member] | Asia Pacific [Member]
Goodwill And Other Intangible Assets [Line Items]
Percentage of fair value excess by carrying value	38.00%
Executive Search [Member] | Europe [Member]
Goodwill And Other Intangible Assets [Line Items]
Percentage of fair value excess by carrying value	69.00%
Executive Search [Member] | Americas [Member]
Goodwill And Other Intangible Assets [Line Items]
Percentage of fair value excess by carrying value	124.00%
Executive Search [Member] | Asia Pacific [Member]
Goodwill And Other Intangible Assets [Line Items]
Percentage of fair value excess by carrying value	34.00%
Executive Search [Member] | Co Company [Member] | Europe [Member]
Goodwill And Other Intangible Assets [Line Items]
Goodwill acquired		$ 10,745
Leadership Consulting [Member]
Goodwill And Other Intangible Assets [Line Items]
Percentage of fair value excess by carrying value	46.00%