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Overview and Summary of Significant Accounting Policies - Revenue Recognition (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
Accounting Policies [Abstract]
Contract asset with customer	$ 93.7		$ 93.7		$ 65.1
Revenue recognized, advance billings balances	8.8	$ 23.1	16.1	$ 69.8
Segment Reporting [Line Items]
Revenues	658.7	647.5	1,230.4	1,195.1
Construction Products \| Intersubsegment Eliminations
Segment Reporting [Line Items]
Revenues	(12.8)	(10.3)	(17.3)	(14.4)
Construction Products \| Operating segments
Segment Reporting [Line Items]
Revenues	357.0	354.5	633.3	617.3
Engineered Structures \| Operating segments
Segment Reporting [Line Items]
Revenues	301.7	293.0	597.1	577.8
Aggregates \| Construction Products
Segment Reporting [Line Items]
Revenues	191.5	194.0	366.0	359.3
Specialty materials and asphalt \| Construction Products
Segment Reporting [Line Items]
Revenues	134.2	133.3	204.6	206.5
Total Construction Materials \| Construction Products
Segment Reporting [Line Items]
Revenues	312.9	317.0	553.3	551.4
Construction Site Support \| Construction Products
Segment Reporting [Line Items]
Revenues	44.1	37.5	80.0	65.9
Utility and related structures \| Engineered Structures
Segment Reporting [Line Items]
Revenues	230.6	205.2	456.0	401.0
Wind towers \| Engineered Structures
Segment Reporting [Line Items]
Revenues	$ 71.1	$ 87.8	$ 141.1	$ 176.8