Fair Value Measurements - Schedule of Fair Value of Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Mar. 31, 2024
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Partnership and LLC interests	$ 158,222	$ 131,858
Equity Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Partnership and LLC interests	24,553	17,028
Partnership And LLC Interests
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Partnership and LLC interests	133,669	114,830
Level III
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Partnership and LLC interests	16,500	13,700
Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration obligation	56,312	53,449
Total liabilities	56,312	53,449
Total assets	16,466	13,694
Fair Value, Recurring \| Equity Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Partnership and LLC interests	10,697	12,421
Fair Value, Recurring \| Partnership And LLC Interests
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Partnership and LLC interests	5,769	1,273
Fair Value, Recurring \| Level I
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration obligation	0	0
Total liabilities	0	0
Total assets	0	0
Fair Value, Recurring \| Level I \| Equity Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Partnership and LLC interests	0	0
Fair Value, Recurring \| Level I \| Partnership And LLC Interests
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Partnership and LLC interests	0	0
Fair Value, Recurring \| Level II
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration obligation	0	0
Total liabilities	0	0
Total assets	0	0
Fair Value, Recurring \| Level II \| Equity Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Partnership and LLC interests	0	0
Fair Value, Recurring \| Level II \| Partnership And LLC Interests
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Partnership and LLC interests	0	0
Fair Value, Recurring \| Level III
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration obligation	56,312	53,449
Total liabilities	56,312	53,449
Total assets	16,466	13,694
Fair Value, Recurring \| Level III \| Equity Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Partnership and LLC interests	10,697	12,421
Fair Value, Recurring \| Level III \| Partnership And LLC Interests
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Partnership and LLC interests	$ 5,769	$ 1,273