Income Taxes	3 Months Ended
Jun. 30, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes HLI is the sole managing member of HLA, which is organized as a limited liability company and treated as a “flow-through” entity for income tax purposes. As a “flow-through” entity, HLA is not subject to income taxes apart from certain local taxes assessed at the limited liability company level and foreign taxes attributable to its operations in foreign jurisdictions. Any taxable income or loss generated by HLA is passed through to and included in the taxable income or loss of its members, including HLI, on a pro rata basis. As a result, the Company does not record income taxes on pre-tax income or loss attributable to the non-controlling interests in the general partnerships and HLA, except for certain local and foreign taxes discussed above. HLI is subject to U.S. federal and applicable state corporate income taxes with respect to its allocable share of any taxable income from HLA. The Company’s effective tax rate used for interim periods is based on an estimated annual effective tax rate including the tax effect of items required to be recorded discretely in the interim period in which those items occur. The effective tax rate is dependent on many factors, including the estimated amount of income subject to income tax; therefore, the effective tax rate can vary from period to period. The Company’s effective tax rate was 6.5% and 12.6% for the three months ended June 30, 2018 and 2017, respectively. These rates were less than the statutory rate primarily due to the portion of income allocated to the non-controlling entities and discrete tax adjustments recorded in the three months ended June 30, 2018. On December 22, 2017, the Tax Cuts and Jobs Act (the “Tax Act”) was enacted, resulting in significant changes to U.S. federal income tax laws which include, but are not limited to: (1) a reduction of the corporate income tax rate from a maximum graduated tax rate of 35% to a flat tax rate of 21% effective January 1, 2018, (2) a limitation of the tax deduction for interest expense, (3) expensing the cost of acquired qualified property, and (4) a one-time transition tax on accumulated, undistributed earnings of certain foreign subsidiaries. The SEC Staff issued Staff Accounting Bulletin No. 118 (“SAB 118”) in December 2017 which addresses situations where the information needed to account for the income tax effects of the Tax Act is either not available, not prepared, or incomplete for the reporting period in which the Tax Act was enacted. During the year ended March 31, 2018, the Company recorded a provisional amount as a reasonable estimate of the impact of the Tax Act in accordance with SAB 118. As of June 30, 2018, the Company has not completed the accounting for the effects of the Tax Act and there have been no changes to the previously recorded provisional amounts. The Company evaluates the realizability of its deferred tax asset on a quarterly basis and adjusts the valuation allowance when it is more likely than not that all or a portion of the deferred tax asset may not be realized. As of June 30, 2018, the Company had no unrecognized tax positions and believes there will be no changes to uncertain tax positions within the next 12 months. Tax Receivable Agreement HLI’s purchase of HLA Class A units in connection with the IPO, and the subsequent and future exchanges by holders of HLA units for shares of HLI’s Class A common stock pursuant to the exchange agreement, are expected to result in increases in HLI’s share of the tax basis of the tangible and intangible assets of HLA. This will increase the tax depreciation and amortization deductions that otherwise would not have been available to HLI. These increases in tax basis and tax depreciation and amortization deductions are expected to reduce the amount of cash taxes that HLI would otherwise be required to pay in the future. On March 6, 2017, HLI entered into a tax receivable agreement (“TRA”) with the other members of HLA that requires HLI to pay exchanging HLA unitholders (the “TRA Recipients”) 85% of the amount of cash savings, if any, in U.S. federal, state, and local income tax that HLI actually realizes (or, under certain circumstances, is deemed to realize) as a result of the increases in tax basis in connection with exchanges by the TRA Recipients described above and certain other tax benefits attributable to payments under the TRA. Based on current projections, we anticipate having sufficient taxable income to utilize these tax attributes and receive corresponding tax deductions in future periods. Changes in the projected liability resulting from the TRA may occur based on changes in anticipated future taxable income, changes in applicable tax rates or other changes in tax attributes that may occur and could affect the expected future tax benefits to be received by us. The payable to related parties pursuant to the TRA increased to $34,335 as of June 30, 2018 from $34,133 as of March 31, 2018 as a result of being re-measured due to changes in state tax rates. The change in liability was recorded to other non-operating loss in the Condensed Consolidated Statements of Income. No amounts were paid to TRA Recipients during the three months ended June 30, 2018.

Income Taxes

HLI is the sole managing member of HLA, which is organized as a limited liability company and treated as a “flow-through” entity for income tax purposes. As a “flow-through” entity, HLA is not subject to income taxes apart from certain local taxes assessed at the limited liability company level and foreign taxes attributable to its operations in foreign jurisdictions. Any taxable income or loss generated by HLA is passed through to and included in the taxable income or loss of its members, including HLI, on a pro rata basis. As a result, the Company does not record income taxes on pre-tax income or loss attributable to the non-controlling interests in the general partnerships and HLA, except for certain local and foreign taxes discussed above. HLI is subject to U.S. federal and applicable state corporate income taxes with respect to its allocable share of any taxable income from HLA.

The Company’s effective tax rate used for interim periods is based on an estimated annual effective tax rate including the tax effect of items required to be recorded discretely in the interim period in which those items occur. The effective tax rate is dependent on many factors, including the estimated amount of income subject to income tax; therefore, the effective tax rate can vary from period to period.

The Company’s effective tax rate was 6.5% and 12.6% for the three months ended June 30, 2018 and 2017, respectively. These rates were less than the statutory rate primarily due to the portion of income allocated to the non-controlling entities and discrete tax adjustments recorded in the three months ended June 30, 2018.

On December 22, 2017, the Tax Cuts and Jobs Act (the “Tax Act”) was enacted, resulting in significant changes to U.S. federal income tax laws which include, but are not limited to: (1) a reduction of the corporate income tax rate from a maximum graduated tax rate of 35% to a flat tax rate of 21% effective January 1, 2018, (2) a limitation of the tax deduction for interest expense, (3) expensing the cost of acquired qualified property, and (4) a one-time transition tax on accumulated, undistributed earnings of certain foreign subsidiaries. The SEC Staff issued Staff Accounting Bulletin No. 118 (“SAB 118”) in December 2017 which addresses situations where the information needed to account for the income tax effects of the Tax Act is either not available, not prepared, or incomplete for the reporting period in which the Tax Act was enacted. During the year ended March 31, 2018, the Company recorded a provisional amount as a reasonable estimate of the impact of the Tax Act in accordance with SAB 118. As of June 30, 2018, the Company has not completed the accounting for the effects of the Tax Act and there have been no changes to the previously recorded provisional amounts.

The Company evaluates the realizability of its deferred tax asset on a quarterly basis and adjusts the valuation allowance when it is more likely than not that all or a portion of the deferred tax asset may not be realized.

As of June 30, 2018, the Company had no unrecognized tax positions and believes there will be no changes to uncertain tax positions within the next 12 months.

Tax Receivable Agreement

HLI’s purchase of HLA Class A units in connection with the IPO, and the subsequent and future exchanges by holders of HLA units for shares of HLI’s Class A common stock pursuant to the exchange agreement, are expected to result in increases in HLI’s share of the tax basis of the tangible and intangible assets of HLA. This will increase the tax depreciation and amortization deductions that otherwise would not have been available to HLI. These increases in tax basis and tax depreciation and amortization deductions are expected to reduce the amount of cash taxes that HLI would otherwise be required to pay in the future. On March 6, 2017, HLI entered into a tax receivable agreement (“TRA”) with the other members of HLA that requires HLI to pay exchanging HLA unitholders (the “TRA Recipients”) 85% of the amount of cash savings, if any, in U.S. federal, state, and local income tax that HLI actually realizes (or, under certain circumstances, is deemed to realize) as a result of the increases in tax basis in connection with exchanges by the TRA Recipients described above and certain other tax benefits attributable to payments under the TRA.

Based on current projections, we anticipate having sufficient taxable income to utilize these tax attributes and receive corresponding tax deductions in future periods. Changes in the projected liability resulting from the TRA may occur based on changes in anticipated future taxable income, changes in applicable tax rates or other changes in tax attributes that may occur and could affect the expected future tax benefits to be received by us.

The payable to related parties pursuant to the TRA increased to $34,335 as of June 30, 2018 from $34,133 as of March 31, 2018 as a result of being re-measured due to changes in state tax rates. The change in liability was recorded to other non-operating loss in the Condensed Consolidated Statements of Income. No amounts were paid to TRA Recipients during the three months ended June 30, 2018.