Basic and Diluted Earnings Per Share - Basic and Diluted Earnings per Common Share Attributable to Common Stockholders (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Apr. 30, 2021	Jan. 31, 2021	Oct. 31, 2020	Jul. 31, 2020	Apr. 30, 2020	Jan. 31, 2020	Oct. 31, 2019	Jul. 31, 2019	Apr. 30, 2021	Apr. 30, 2020	Apr. 30, 2019
Earnings Per Share Disclosure [Line Items]
Net income attributable to Korn Ferry	$ 66,190	$ 51,319	$ 27,778	$ (30,833)	$ (802)	$ 19,993	$ 42,804	$ 42,951	$ 114,454	$ 104,946	$ 102,651
Less: distributed and undistributed earnings to nonvested restricted stockholders									2,763	1,140	1,066
Basic net earnings attributable to common stockholders									111,691	103,806	101,585
Add: undistributed earnings to nonvested restricted stockholders									2,185	901	831
Less: reallocation of undistributed earnings to nonvested restricted stockholders									2,165	894	820
Diluted net earnings attributable to common stockholders									$ 111,711	$ 103,813	$ 101,596
Basic weighted-average number of common shares outstanding									52,928	54,342	55,311
Diluted weighted-average number of common shares outstanding									53,405	54,767	56,096
Basic earnings per share	$ 1.22	$ 0.95	$ 0.51	$ (0.58)	$ (0.02)	$ 0.37	$ 0.78	$ 0.77	$ 2.11	$ 1.91	$ 1.84
Diluted earnings per share	$ 1.21	$ 0.94	$ 0.51	$ (0.58)	$ (0.02)	$ 0.36	$ 0.77	$ 0.76	$ 2.09	$ 1.90	$ 1.81
ESPP
Earnings Per Share Disclosure [Line Items]
Effect of dilutive securities									1	58	34
Restricted Stock
Earnings Per Share Disclosure [Line Items]
Effect of dilutive securities									476	367	750
Stock Options
Earnings Per Share Disclosure [Line Items]
Effect of dilutive securities											1