Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Current [Abstract]
Federal	$ 31,986	$ 18,966	$ 4,384
State	5,492	3,108	1,436
Foreign	6	0	0
Total current tax expense benefit	37,484	22,074	5,820
Deferred [Abstract]
Federal	5,376	3,341	395
State	365	387	114
Foreign	0	0	0
Total deferred tax expense benefit	5,741	3,728	509
Income tax expense	$ 43,225	$ 25,802	$ 6,329
Effective Income Tax Rate Reconciliation [Abstract]
Statutory federal tax rate	21.00%	21.00%	21.00%
Income attributable to non-controlling interests and nontaxable income	(2.30%)	(5.50%)	(12.40%)
State income taxes, net of federal benefit	2.90%	2.40%	2.30%
Other	0.40%	0.80%	0.60%
Effective income tax rate	22.00%	18.70%	11.50%
Deferred tax assets [Abstract]
Investment in partnerships	$ 0	$ 19,293
Tax receivable agreement	11,609	9,817
Other	3	0
Total	11,612	29,110
Valuation allowance	0	0
Total deferred tax assets	11,612	29,110
Deferred tax liabilities [Abstract]
Investment in partnerships	2,410	0
Fixed assets	66	0
Intangibles	703	0
Total deferred tax liabilities	3,179	0
Deferred tax assets, net	8,433	29,110
Tax receivable agreement liability	$ 46,400	$ 40,100
Percentage of net cash savings	85.00%