Fair Value Measurements - Recurring Measurements (Details) - USD ($) $ in Millions	Mar. 31, 2025	Dec. 31, 2024
Assets:
Derivative assets	$ 6.4	$ 5.7
Fair Value, Measurements, Recurring
Assets:
Derivative assets	6.4	5.7
Pension plan investments	26.2	25.9
Total recurring assets at fair value	32.6	31.6
Derivative liabilities:
Total derivative liabilities	0.0	0.0
Precious metals obligations	0.0	(5.2)
Liability awards	(28.3)	(67.8)
Total recurring liabilities at fair value	(28.3)	(73.0)
Fair Value, Measurements, Recurring | Inventory Financing Obligations
Derivative liabilities:
Total derivative liabilities	0.0	0.0
Fair Value, Measurements, Recurring | Inventory Financing Obligations
Assets:
Derivative assets	6.4	5.7
Fair Value, Measurements, Recurring | Level 1
Assets:
Derivative assets	0.0	0.0
Pension plan investments	3.7	3.7
Total recurring assets at fair value	3.7	3.7
Derivative liabilities:
Total derivative liabilities	0.0	0.0
Precious metals obligations	0.0	(5.2)
Liability awards	(28.3)	(67.8)
Total recurring liabilities at fair value	(28.3)	(73.0)
Fair Value, Measurements, Recurring | Level 1 | Inventory Financing Obligations
Derivative liabilities:
Total derivative liabilities	0.0	0.0
Fair Value, Measurements, Recurring | Level 1 | Inventory Financing Obligations
Assets:
Derivative assets	0.0	0.0
Fair Value, Measurements, Recurring | Level 2
Assets:
Derivative assets	0.0	0.0
Pension plan investments	22.5	22.2
Total recurring assets at fair value	22.5	22.2
Derivative liabilities:
Total derivative liabilities	0.0	0.0
Precious metals obligations	0.0	0.0
Liability awards	0.0	0.0
Total recurring liabilities at fair value	0.0	0.0
Fair Value, Measurements, Recurring | Level 2 | Inventory Financing Obligations
Derivative liabilities:
Total derivative liabilities	0.0	0.0
Fair Value, Measurements, Recurring | Level 2 | Inventory Financing Obligations
Assets:
Derivative assets	0.0	0.0
Fair Value, Measurements, Recurring | Level 3
Assets:
Derivative assets	6.4	5.7
Pension plan investments	0.0	0.0
Total recurring assets at fair value	6.4	5.7
Derivative liabilities:
Total derivative liabilities	0.0	0.0
Precious metals obligations	0.0	0.0
Liability awards	0.0	0.0
Total recurring liabilities at fair value	0.0	0.0
Fair Value, Measurements, Recurring | Level 3 | Inventory Financing Obligations
Derivative liabilities:
Total derivative liabilities	0.0	0.0
Fair Value, Measurements, Recurring | Level 3 | Inventory Financing Obligations
Assets:
Derivative assets	$ 6.4	$ 5.7