Goodwill - Schedule of Goodwill by Reporting Segment (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024	Dec. 31, 2023
Goodwill [Abstract]
Goodwill	$ 164.4		$ 164.4		$ 79.0	$ 80.3
Accumulated impairment losses	(54.0)		(54.0)		(54.0)	(34.0)
Goodwill	110.4		110.4		25.0	46.3
Foreign currency translation			0.3		(1.1)
Impairment	0.0	$ 0.0	0.0	$ 20.2	20.2
Acquisitions	85.1		85.1
Goodwill, period increase (decrease)			85.4		(21.3)
Operating Segments
Goodwill [Abstract]
Impairment	0.0	$ 0.0	0.0	$ 20.2
Infrastructure Solutions | Operating Segments
Goodwill [Abstract]
Goodwill	47.4		47.4		46.8	48.0
Accumulated impairment losses	(21.8)		(21.8)		(21.8)	(21.8)
Goodwill	25.6		25.6		25.0	26.2
Foreign currency translation			0.6		(1.2)
Impairment					0.0
Acquisitions			0.0
Goodwill, period increase (decrease)			0.6		(1.2)
Materials Solutions | Operating Segments
Goodwill [Abstract]
Goodwill	117.0		117.0		32.2	32.3
Accumulated impairment losses	(32.2)		(32.2)		(32.2)	(12.2)
Goodwill	$ 84.8		84.8		0.0	$ 20.1
Foreign currency translation			(0.3)		0.1
Impairment					20.2
Acquisitions			85.1
Goodwill, period increase (decrease)			$ 84.8		$ (20.1)