Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Numerator:
Net income (loss) attributable to StepStone Group Inc. – Basic	$ 58,091	$ (18,398)	$ 193,885
Net income (loss) attributable to StepStone Group Inc. – Diluted	$ 60,744	$ (18,398)	$ 205,617
Denominator:
Weighted-average shares of Class A common stock outstanding – Basic (in shares)	63,489,135	61,884,671	49,833,760
Weighted-average shares of Class A common stock outstanding - Diluted (in shares)	66,544,038	61,884,671	53,600,250
Net income (loss) per share of Class A common stock:
Basic (in dollars per share)	$ 0.91	$ (0.30)	$ 3.89
Diluted (in dollars per share)	$ 0.91	$ (0.30)	$ 3.84
Restricted Stock Units (RSUs)
Numerator:
Incremental income from assumed vesting of units	$ 451	$ 0	$ 4,043
Denominator:
Assumed vesting and exchange of restricted share units and Class B2 units (in shares)	512,152	0	1,289,809
Class B2 units
Numerator:
Incremental income from assumed vesting of units	$ 2,202	$ 0	$ 7,689
Denominator:
Assumed vesting and exchange of restricted share units and Class B2 units (in shares)	2,542,751	0	2,476,681