Segments - Financial Highlights by Operating Segment (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Oct. 31, 2020	Oct. 31, 2019	Oct. 31, 2020	Oct. 31, 2019
Segment Reporting Information [Line Items]
Total revenue	$ 437,789	$ 504,177	$ 784,672	$ 1,000,375
Net income (loss) attributable to Korn Ferry	27,778	42,804	(3,055)	85,755
Net income attributable to noncontrolling interest	300	228	278	927
Other income, net	(277)	(1,133)	(11,439)	(2,959)
Interest expense, net	7,494	4,210	14,388	8,267
Income tax provision	12,877	15,760	4,205	30,213
Operating income (loss)	48,172	61,869	4,377	122,203
Depreciation and amortization	15,298	12,715	30,333	25,492
Other income (loss), net	277	1,133	11,439	2,959
EBITDA	63,747	75,717	46,149	150,654
Integration/acquisition costs		2,615	737	2,615
Restructuring charges, net	2,407		29,894
Adjusted EBITDA	66,154	78,332	76,780	153,269
Fee Revenue
Segment Reporting Information [Line Items]
Total revenue	435,439	492,389	779,536	976,938
Operating Segments | Consulting
Segment Reporting Information [Line Items]
Total revenue	127,051	148,198	226,641	289,534
Operating income (loss)	14,621	9,826	3,694	21,609
Depreciation and amortization	4,063	4,357	8,072	8,771
Other income (loss), net	336	386	1,124	911
EBITDA	19,020	14,569	12,890	31,291
Restructuring charges, net	1,143		13,877
Adjusted EBITDA	20,163	14,569	26,767	31,291
Operating Segments | Digital
Segment Reporting Information [Line Items]
Total revenue	75,038	65,724	131,060	123,708
Operating income (loss)	15,823	18,565	13,196	32,573
Depreciation and amortization	7,005	3,685	13,731	7,324
Other income (loss), net	202	134	620	335
EBITDA	23,030	22,384	27,547	40,232
Integration/acquisition costs			556
Restructuring charges, net	54		2,924
Adjusted EBITDA	23,084	22,384	31,027	40,232
Operating Segments | Executive Search
Segment Reporting Information [Line Items]
Total revenue	148,599	191,959	269,485	389,972
Operating income (loss)	25,628	41,229	13,318	86,865
Depreciation and amortization	1,523	1,963	3,092	3,994
Other income (loss), net	195	846	9,830	2,070
EBITDA	27,346	44,038	26,240	92,929
Restructuring charges, net	882		10,042
Adjusted EBITDA	28,228	44,038	36,282	92,929
Operating Segments | Executive Search | North America
Segment Reporting Information [Line Items]
Total revenue	91,609	117,077	161,465	232,523
Operating income (loss)	20,491	28,124	14,756	58,446
Depreciation and amortization	716	869	1,446	1,770
Other income (loss), net	(9)	637	9,333	1,777
EBITDA	21,198	29,630	25,535	61,993
Restructuring charges, net	(12)		963
Adjusted EBITDA	21,186	29,630	26,498	61,993
Operating Segments | Executive Search | EMEA
Segment Reporting Information [Line Items]
Total revenue	31,714	40,441	61,909	87,753
Operating income (loss)	1,509	6,511	(4,710)	13,822
Depreciation and amortization	355	450	717	906
Other income (loss), net	31	107	50	119
EBITDA	1,895	7,068	(3,943)	14,847
Restructuring charges, net	922		8,470
Adjusted EBITDA	2,817	7,068	4,527	14,847
Operating Segments | Executive Search | Asia Pacific
Segment Reporting Information [Line Items]
Total revenue	20,820	26,168	38,160	53,836
Operating income (loss)	3,253	5,803	4,114	12,796
Depreciation and amortization	250	329	525	675
Other income (loss), net	166	72	392	87
EBITDA	3,669	6,204	5,031	13,558
Restructuring charges, net	(28)		204
Adjusted EBITDA	3,641	6,204	5,235	13,558
Operating Segments | Executive Search | Latin America
Segment Reporting Information [Line Items]
Total revenue	4,456	8,273	7,951	15,860
Operating income (loss)	375	791	(842)	1,801
Depreciation and amortization	202	315	404	643
Other income (loss), net	7	30	55	87
EBITDA	584	1,136	(383)	2,531
Restructuring charges, net			405
Adjusted EBITDA	584	1,136	22	2,531
Operating Segments | RPO & Professional Search
Segment Reporting Information [Line Items]
Total revenue	87,101	98,296	157,486	197,161
Operating income (loss)	12,502	15,094	14,667	30,135
Depreciation and amortization	945	990	1,885	1,982
Other income (loss), net	24	54	220	128
EBITDA	13,471	16,138	16,772	32,245
Restructuring charges, net	328		3,051
Adjusted EBITDA	13,799	16,138	19,823	32,245
Operating Segments | Fee Revenue | Consulting
Segment Reporting Information [Line Items]
Total revenue	126,685	144,036	226,003	281,578
Operating Segments | Fee Revenue | Digital
Segment Reporting Information [Line Items]
Total revenue	75,043	65,724	131,016	123,708
Operating Segments | Fee Revenue | Executive Search
Segment Reporting Information [Line Items]
Total revenue	148,060	187,855	268,203	381,054
Operating Segments | Fee Revenue | Executive Search | North America
Segment Reporting Information [Line Items]
Total revenue	91,168	113,818	160,483	225,540
Operating Segments | Fee Revenue | Executive Search | EMEA
Segment Reporting Information [Line Items]
Total revenue	31,629	39,821	61,710	86,351
Operating Segments | Fee Revenue | Executive Search | Asia Pacific
Segment Reporting Information [Line Items]
Total revenue	20,807	25,944	38,059	53,306
Operating Segments | Fee Revenue | Executive Search | Latin America
Segment Reporting Information [Line Items]
Total revenue	4,456	8,272	7,951	15,857
Operating Segments | Fee Revenue | RPO & Professional Search
Segment Reporting Information [Line Items]
Total revenue	85,651	94,774	154,314	190,598
Corporate
Segment Reporting Information [Line Items]
Operating income (loss)	(20,402)	(22,845)	(40,498)	(48,979)
Depreciation and amortization	1,762	1,720	3,553	3,421
Other income (loss), net	(480)	(287)	(355)	(485)
EBITDA	(19,120)	(21,412)	(37,300)	(46,043)
Integration/acquisition costs		2,615	181	2,615
Adjusted EBITDA	$ (19,120)	$ (18,797)	$ (37,119)	$ (43,428)