Goodwill and Other Intangible Assets - Changes in Carrying Amount of Goodwill by Segment (Detail) (USD $) In Thousands, unless otherwise specified	0 Months Ended	12 Months Ended
	Oct. 31, 2011	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Goodwill [Line Items]
Beginning Balance		$ 120,940	$ 90,696	$ 109,888
Goodwill impairment	0			(23,507)
Exchange rate fluctuations		(395)	537	385
Ending Balance		123,274	120,940	90,696
Iron Hill [Member]
Goodwill [Line Items]
Iron Hill earnout adjustment				3,930
Senn Delaney [Member]
Goodwill [Line Items]
Scambler MacGregor acquisition			29,707
Scambler MacGregor [Member]
Goodwill [Line Items]
Scambler MacGregor acquisition		2,729
Europe [Member]
Goodwill [Line Items]
Goodwill impairment				(23,507)
Executive Search and Leadership Consulting [Member] | Americas [Member]
Goodwill [Line Items]
Beginning Balance		82,941	82,814	78,989
Exchange rate fluctuations		(301)	127	(105)
Ending Balance		82,640	82,941	82,814
Executive Search and Leadership Consulting [Member] | Americas [Member] | Iron Hill [Member]
Goodwill [Line Items]
Iron Hill earnout adjustment				3,930
Executive Search and Leadership Consulting [Member] | Europe [Member]
Goodwill [Line Items]
Beginning Balance				22,982
Goodwill impairment				(23,507)
Exchange rate fluctuations				525
Ending Balance
Executive Search and Leadership Consulting [Member] | Europe [Member] | Senn Delaney [Member]
Goodwill [Line Items]
Scambler MacGregor acquisition
Executive Search and Leadership Consulting [Member] | Europe [Member] | Scambler MacGregor [Member]
Goodwill [Line Items]
Scambler MacGregor acquisition
Executive Search and Leadership Consulting [Member] | Asia Pacific [Member]
Goodwill [Line Items]
Beginning Balance		8,292	7,882	7,917
Goodwill impairment
Exchange rate fluctuations		(167)	410	(35)
Ending Balance		10,854	8,292	7,882
Executive Search and Leadership Consulting [Member] | Asia Pacific [Member] | Iron Hill [Member]
Goodwill [Line Items]
Iron Hill earnout adjustment
Executive Search and Leadership Consulting [Member] | Asia Pacific [Member] | Scambler MacGregor [Member]
Goodwill [Line Items]
Scambler MacGregor acquisition		2,729
Culture Shaping [Member]
Goodwill [Line Items]
Beginning Balance		29,707
Goodwill impairment
Exchange rate fluctuations		73
Ending Balance		29,780
Culture Shaping [Member] | Iron Hill [Member]
Goodwill [Line Items]
Iron Hill earnout adjustment
Culture Shaping [Member] | Senn Delaney [Member]
Goodwill [Line Items]
Scambler MacGregor acquisition			$ 29,707