CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Earnings Per Share, Diluted [Abstract]
Revenues	$ 368.9	$ 308.5	$ 887.1	$ 1,137.7
Cost of sales	283.9	234.6	698.7	902.9
Selling, General and Administrative Expense	26.4	24.1	71.3	69.9
Equity in earnings of unconsolidated ventures	0.0	0.0	0.0	(1.1)
Gain on sale of assets	0.0	(2.7)	(1.6)	(3.2)
Interest and other income	(3.8)	(0.2)	(7.5)	(0.2)
Income before income taxes	62.4	52.7	126.2	169.4
Income tax expense	15.6	13.0	31.7	41.4
Net income	$ 46.8	$ 39.7	$ 94.5	$ 128.0
Basic net income per common share	$ 0.94	$ 0.80	$ 1.89	$ 2.57
Weighted average number of common shares	50,056,126	49,879,394	49,963,326	49,794,566
Diluted net income per common share	$ 0.93	$ 0.80	$ 1.89	$ 2.57
Adjusted weighted average number of common shares	50,175,794	49,893,640	50,028,451	49,834,891