Income Taxes Computed at Federal Statutory Rate (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Income Tax Disclosure [Abstract]
Income from continuing operations before taxes	$ (50,642)	$ (15,201)	$ 96,244	$ 18,153	$ (26,171)	$ (33,196)	$ 86,294	$ 19,002	$ 48,554	$ 45,929	$ 49,026
Provision for income taxes:
Tax at Federal statutory rate									10,196	9,645	10,295
State taxes net of federal benefit									3,145	3,401	3,251
Permanent differences									286	520	249
Expiration of State NOL									2,160	0	0
Change in valuation allowance									(2,328)	252	208
Other									(128)	166	(265)
Income tax expense									$ 13,331	$ 13,984	$ 13,738