Quarterly Results (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Apr. 30, 2017	Jan. 31, 2017	Oct. 31, 2016	Jul. 31, 2016	Apr. 30, 2016	Jan. 31, 2016	Oct. 31, 2015	Jul. 31, 2015	Apr. 30, 2017	Apr. 30, 2016	Apr. 30, 2015
Quarterly Financial Information [Line Items]
Fee revenue	$ 406,065	$ 381,918	$ 401,917	$ 375,621	$ 399,960	$ 344,158	$ 280,600	$ 267,394	$ 1,565,521	$ 1,292,112	$ 1,028,152
Operating income (loss)	32,834	30,542	46,548	4,516	4,842	(14,067)	29,013	32,904	114,440	52,692	114,028
Net income (loss)	27,736	24,378	31,056	4,068	6,375	(15,995)	17,971	23,082	87,238	31,433	88,357
Net income (loss) attributable to Korn/Ferry International	$ 26,924	$ 23,897	$ 30,152	$ 3,208	$ 5,855	$ (15,995)	$ 17,971	$ 23,082	$ 84,181	$ 30,913	$ 88,357
Basic	$ 0.48	$ 0.42	$ 0.53	$ 0.06	$ 0.10	$ (0.30)	$ 0.36	$ 0.46	$ 1.48	$ 0.58	$ 1.78
Diluted	$ 0.47	$ 0.42	$ 0.52	$ 0.06	$ 0.10	$ (0.30)	$ 0.35	$ 0.46	$ 1.47	$ 0.58	$ 1.76