Commitments and Contingencies - Incentive Fees (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Mar. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Carried interest still subject to contingencies	$ 1,064,430	$ 648,772
Incentive fees, unrecorded estimate	$ 266,107	$ 162,193

Incentive Fee Revenue, Carried Interest, Unrecorded Estimate

No definition available.

Name:	hlne_IncentiveFeeRevenueCarriedInterestUnrecordedEstimate
Namespace Prefix:	hlne_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant