Income Tax Matters - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Deferred income tax assets:
Loss and credit carryforwards	$ 47.7	$ 51.5
Pension benefits	2.9	7.1
Other assets	36.3	29.0
Lease assets	10.6	11.7
Inventories	46.9	50.4
Excess interest carryforward	12.2
Research & development capitalization	8.7
Valuation allowances	(3.7)	(4.6)
Total deferred income tax assets	161.6	145.1
Deferred income tax liabilities:
Property, plant and equipment	(147.0)	(138.9)
Lease liability	(9.3)	(10.9)
Undistributed foreign earnings	(2.7)	(2.4)
Total deferred income tax liabilities	(159.0)	(152.2)
Net deferred income tax assets	$ 2.6
Net deferred income tax liabilities		$ (7.1)