Summary of Significant Accounting Policies (Policies)	3 Months Ended
Jun. 30, 2022
Accounting Policies [Abstract]
Basis of Presentation	Basis of PresentationThe accompanying unaudited condensed consolidated financial statements of the Company have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) for interim financial information. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. Management believes it has made all necessary adjustments (which consisted of only normal recurring items) so that the condensed consolidated financial statements are presented fairly and that estimates made in preparing the condensed consolidated financial statements are reasonable and prudent. Results of operations for the three months ended June 30, 2022 are not necessarily indicative of the results that may be expected for the year ending March 31, 2023. These unaudited condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements included in HLI’s Annual Report on Form 10-K for the fiscal year ended March 31, 2022.
Accounting for Differing Fiscal Periods	Accounting for Differing Fiscal Periods The Partnerships primarily have a fiscal year end as of December 31, and the Company accounts for its investments in the Partnerships using a three-month lag due to the timing of financial information received from the investments held by the Partnerships. The Partnerships primarily invest in private equity funds, which generally require at least 90 days following the calendar year end to present audited financial statements. The Company records its share of capital contributions to and distributions from the Partnerships in investments in the Condensed Consolidated Balance Sheets during the three-month lag period.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The Company utilizes a hierarchy that prioritizes fair value measurements based on the types of inputs used for the various valuation techniques (market approach, income approach, and cost approach). The levels of the hierarchy are described below: •Level 1: Values are determined using quoted market prices for identical financial instruments in an active market. •Level 2: Values are determined using quoted prices for similar financial instruments and valuation models whose inputs are observable. •Level 3: Values are determined using pricing models that use significant inputs that are primarily unobservable, discounted cash flow methodologies or similar techniques, as well as instruments for which the determination of fair value requires significant management judgment or estimation. The carrying amount of cash and cash equivalents, fees receivable, and accounts payable approximate fair value due to the immediate or short-term maturity of these financial instruments.
Reclassifications	Reclassifications Certain prior period amounts have been reclassified to conform to the current period presentation.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In June 2022, the FASB issued Accounting Standard Updated ("ASU") 2022-03, Fair Value Measurement (Topic 820): Fair Value Measurement of Equity Securities Subject to Contractual Sale Restrictions. The amendments in this update clarify the guidance in Topic 820 when measuring the fair value of an equity security subject to contractual sale restrictions and introduce new disclosure requirements related to such equity securities. The amendments are effective for fiscal years beginning after December 15, 2023, with early adoption permitted. The Company is currently evaluating the impact of this guidance on its condensed consolidated financial statements.

Summary of Significant Accounting Policies (Policies)

3 Months Ended

Jun. 30, 2022

Basis of PresentationThe accompanying unaudited condensed consolidated financial statements of the Company have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) for interim financial information. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. Management believes it has made all necessary adjustments (which consisted of only normal recurring items) so that the condensed consolidated financial statements are presented fairly and that estimates made in preparing the condensed consolidated financial statements are reasonable and prudent. Results of operations for the three months ended June 30, 2022 are not necessarily indicative of the results that may be expected for the year ending March 31, 2023. These unaudited condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements included in HLI’s Annual Report on Form 10-K for the fiscal year ended March 31, 2022.

Accounting for Differing Fiscal Periods

The Partnerships primarily have a fiscal year end as of December 31, and the Company accounts for its investments in the Partnerships using a three-month lag due to the timing of financial information received from the investments held by the Partnerships. The Partnerships primarily invest in private equity funds, which generally require at least 90 days following the calendar year end to present audited financial statements. The Company records its share of capital contributions to and distributions from the Partnerships in investments in the Condensed Consolidated Balance Sheets during the three-month lag period.

Fair Value of Financial Instruments

The Company utilizes a hierarchy that prioritizes fair value measurements based on the types of inputs used for the various valuation techniques (market approach, income approach, and cost approach). The levels of the hierarchy are described below:

•Level 1: Values are determined using quoted market prices for identical financial instruments in an active market.

•Level 2: Values are determined using quoted prices for similar financial instruments and valuation models whose inputs are observable.

•Level 3: Values are determined using pricing models that use significant inputs that are primarily unobservable, discounted cash flow methodologies or similar techniques, as well as instruments for which the determination of fair value requires significant management judgment or estimation.

The carrying amount of cash and cash equivalents, fees receivable, and accounts payable approximate fair value due to the immediate or short-term maturity of these financial instruments.

Reclassifications

Certain prior period amounts have been reclassified to conform to the current period presentation.

Recent Accounting Pronouncements

In June 2022, the FASB issued Accounting Standard Updated ("ASU") 2022-03, Fair Value Measurement (Topic 820): Fair Value Measurement of Equity Securities Subject to Contractual Sale Restrictions. The amendments in this update clarify the guidance in Topic 820 when measuring the fair value of an equity security subject to contractual sale restrictions and introduce new disclosure requirements related to such equity securities. The amendments are effective for fiscal years beginning after December 15, 2023, with early adoption permitted. The Company is currently evaluating the impact of this guidance on its condensed consolidated financial statements.