Property, Plant, and Equipment - Components of property, plant, and equipment (Details) - USD ($)
$ in Millions

3 Months Ended

6 Months Ended

Jun. 30, 2026

Jun. 30, 2025

Jun. 30, 2026

Jun. 30, 2025

Dec. 31, 2025

Components of property, plant, and equipment

Property, plant and equipment, at cost

$ 3,138.6

$ 3,138.6

$ 3,005.8

Less accumulated depreciation

(1,040.7)

(1,040.7)

(960.5)

Property, plant, and equipment, net

2,097.9

^[1]

2,097.9

^[1]

2,045.3

Gain on disposition of property, plant, and equipment

19.9

$ 4.5

21.9

$ 8.3

Land

Components of property, plant, and equipment

Property, plant and equipment, at cost

182.4

182.4

194.8

Mineral reserves

Components of property, plant, and equipment

Property, plant and equipment, at cost

1,161.8

1,161.8

1,114.7

Buildings and improvements

Components of property, plant, and equipment

Property, plant and equipment, at cost

366.7

366.7

349.9

Machinery and other

Components of property, plant, and equipment

Property, plant and equipment, at cost

1,289.1

1,289.1

1,210.2

Construction in progress

Components of property, plant, and equipment

Property, plant and equipment, at cost

$ 138.6

$ 138.6

$ 136.2

[1]	(unaudited)