Earnings Per Share - Schedule of Earnings Per Share, Basic and Dilutive (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Numerator:
Income from continuing operations	$ 140,175	$ 158,688	$ 220,718
Loss from discontinued operations, net of tax	0	(77)	(14)
Net income	$ 140,175	$ 158,611	$ 220,704
Denominator:
Basic weighted-average shares (in shares)	30,548	30,353	30,432
Dilutive effect of restricted stock awards (in shares)	397	388	357
Dilutive effect of stock options (in shares)	8	6	7
Diluted weighted-average shares (in shares)	30,953	30,747	30,796
Basic income per share:
Continuing operations (in dollars per share)	$ 4.59	$ 5.23	$ 7.25
Discontinued operations (in dollars per share)	0	0	0
Total (in dollars per share)	4.59	5.23	7.25
Diluted income per share:
Continuing operations (in dollars per share)	4.53	5.16	7.17
Discontinued operations (in dollars per share)	0	0	0
Total (in dollars per share)	$ 4.53	$ 5.16	$ 7.17