Segment Information - Schedule of Company's Reportable Segments (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Revenue
Total revenue	$ 229,008	$ 201,735	$ 668,872	$ 596,617
Adjusted revenue
Total Adjusted revenue	230,711	203,102	673,809	605,443
Operating profit
Operating profit	38,049	5,745	47,297	56,962
Adjusted EBITDA
Total Adjusted EBITDA	66,508	50,139	161,579	148,362
Adjusted EBITDA margin
Total Adjusted EBITDA margin	28.80%	24.70%	24.00%	24.50%
Depreciation and amortization
Total depreciation and amortization	16,655	15,287	51,586	44,776
CEB Segment [Member]
Revenue
Total revenue	179,100	158,709	515,189	463,666
Adjusted revenue
Total Adjusted revenue	180,128	158,709	518,064	463,666
Operating profit
Operating profit	39,750	10,357	52,966	67,683
Adjusted EBITDA
Total Adjusted EBITDA	56,343	45,014	136,328	124,879
Adjusted EBITDA margin
Total Adjusted EBITDA margin	31.30%	28.40%	26.30%	26.90%
Depreciation and amortization
Total depreciation and amortization	7,917	6,964	25,052	21,256
SHL Talent Measurement Segment [Member]
Revenue
Total revenue	49,908	43,026	153,683	132,951
Adjusted revenue
Total Adjusted revenue	50,583	44,393	155,745	141,777
Operating profit
Operating profit	(1,701)	(4,612)	(5,669)	(10,721)
Adjusted EBITDA
Total Adjusted EBITDA	10,165	5,125	25,251	23,483
Adjusted EBITDA margin
Total Adjusted EBITDA margin	20.10%	11.50%	16.20%	16.60%
Depreciation and amortization
Total depreciation and amortization	$ 8,738	$ 8,323	$ 26,534	$ 23,520