Income Taxes - Summary of Reconciliation of Effective Income Tax Rate (Details)	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Income Tax Disclosure [Abstract]
Statutory federal tax rate	21.00%	21.00%	21.00%
Income attributable to non-controlling interests and nontaxable income	(0.20%)	(1.30%)	(0.20%)
State income taxes, net of federal benefit	3.40%	(2.40%)	3.30%
Non-deductible items	(1.10%)	(23.30%)	0.00%
Federal and state credits	0.40%	10.10%	0.00%
Loss on impairment	0.00%	0.00%	(11.40%)
Other	(0.10%)	(1.70%)	(4.70%)
Effective income tax rate	23.40%	2.40%	8.00%