OPERATING SEGMENTS - Schedule of Revenue and Long-Lived Assets by Geographic Area (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Revenues from External Customers and Long-Lived Assets [Line Items]
Total sales	$ 1,243.9	$ 1,117.4	$ 1,204.7
Total long-lived assets	942.5	1,047.5	1,211.6
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Total sales	875.3	825.0	860.4
Total long-lived assets	495.2	580.9	741.7
Canada
Revenues from External Customers and Long-Lived Assets [Line Items]
Total sales	288.6	234.7	269.7
Total long-lived assets	373.9	392.6	398.0
United Kingdom
Revenues from External Customers and Long-Lived Assets [Line Items]
Total sales	65.9	50.7	66.1
Total long-lived assets	66.9	67.5	64.2
Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Total sales	14.1	7.0	8.5
Total long-lived assets	$ 6.5	$ 6.5	$ 7.7