Quarterly Results - Schedule of Unaudited Quarterly Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Apr. 30, 2019	Jan. 31, 2019	Oct. 31, 2018	Jul. 31, 2018	Apr. 30, 2018	Jan. 31, 2018	Oct. 31, 2017	Jul. 31, 2017	Apr. 30, 2019	Apr. 30, 2018	Apr. 30, 2017
Quarterly Financial Information [Line Items]
Fee Revenue									$ 1,973,862	$ 1,819,519	$ 1,621,669
Operating income (loss)	$ 62,275	$ 62,683	$ 70,987	$ (55,119)	$ 64,197	$ 49,846	$ 52,468	$ 41,935	140,826	208,446	120,288
Net income	50,627	45,444	47,317	(38,592)	42,309	27,427	36,732	29,429	104,796	135,897	87,238
Net income attributable to Korn Ferry	$ 50,264	$ 44,964	$ 46,034	$ (38,611)	$ 41,160	$ 27,247	$ 36,331	$ 29,041	$ 102,651	$ 133,779	$ 84,181
Earnings per common share attributable to Korn Ferry:
Basic	$ 0.90	$ 0.81	$ 0.82	$ (0.70)	$ 0.74	$ 0.49	$ 0.65	$ 0.52	$ 1.84	$ 2.39	$ 1.48
Diluted	$ 0.89	$ 0.80	$ 0.81	$ (0.70)	$ 0.73	$ 0.48	$ 0.64	$ 0.51	$ 1.81	$ 2.35	$ 1.47
Fee Revenue
Quarterly Financial Information [Line Items]
Fee Revenue	$ 490,756	$ 474,504	$ 495,205	$ 465,568	$ 475,364	$ 447,581	$ 443,018	$ 401,254	$ 1,926,033	$ 1,767,217	$ 1,565,521