Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2023	Sep. 30, 2022
Deferred tax assets:
Share-based compensation	$ 7.4	$ 4.8
Deferred compensation	5.4	5.1
Net operating loss carryforwards	17.2	18.7
Intangible assets	3.8	6.4
Bad debt reserve	9.6	7.8
Hedging	5.9	17.0
Foreign tax credit carryforwards	0.6	1.6
Other compensation	7.8	8.0
Pension	3.6	2.1
Right of use assets	20.1	23.8
Other	1.1	2.0
Total gross deferred tax assets	82.5	97.3
Less valuation allowance	(12.4)	(15.8)
Deferred tax assets	70.1	81.5
Deferred income tax liabilities:
Unrealized gain on securities	2.8	2.5
Prepaid expenses	5.0	3.8
Property and equipment	1.6	2.0
Right of use liabilities	17.2	20.8
Mark to market on inventory	4.8	0.0
Other deferred liabilities	1.4	0.4
Deferred income tax liabilities	32.8	29.5
Deferred income taxes, net	$ 37.3	$ 52.0