Summary of Significant Accounting Policies - Revenue Recognition (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Apr. 01, 2018
Disaggregation of Revenue [Line Items]
Cumulative effect adjustment on APIC	$ 150,564	$ 107,727
Minimum
Disaggregation of Revenue [Line Items]
Incentive Fees, Percentage Of Profit	5.00%
Maximum
Disaggregation of Revenue [Line Items]
Incentive Fees, Percentage Of Profit	12.50%
Difference between Revenue Guidance in Effect before and after Topic 606 | Accounting Standards Update 2014-09
Disaggregation of Revenue [Line Items]
Cumulative effect adjustment on APIC			$ 411
Cumulative effect adjustment on retained earnings			20
Hamilton Lane Advisors, L.L.C.
Disaggregation of Revenue [Line Items]
Cumulative effect adjustment on retained earnings	$ 87,512	47,090
Cumulative effect adjustment on equity	$ 73,861	$ 77,757
Hamilton Lane Advisors, L.L.C. | Difference between Revenue Guidance in Effect before and after Topic 606 | Accounting Standards Update 2014-09
Disaggregation of Revenue [Line Items]
Cumulative effect adjustment on equity			$ 566