Segment Reporting - Revenues and Operating (Loss) Earnings by Reportable Segment (Details) $ in Millions	3 Months Ended
	Mar. 31, 2026 USD ($) segment	Mar. 31, 2025 USD ($)
Segment Reporting, Disclosure of Entity's Reportable Segments [Abstract]
Number of reportable segments | segment	3
Revenues	$ 144.7	$ 154.0
Cost of sales	119.1	123.8
Depreciation and amortization	21.9	24.7
Selling, general and administrative	15.4	21.6
Segment operating income	(12.1)	(16.5)
Unallocated corporate expenses	(7.9)	(11.2)
Interest income	0.0	0.3
Interest expense	(11.7)	(10.3)
Loss on debt extinguishment	0.0	(1.2)
Net loss before income tax	(23.8)	(27.7)
Cost of Product and Service Sold
Segment Reporting, Disclosure of Entity's Reportable Segments [Abstract]
Unallocated corporate expenses	(0.9)	(0.8)
Depreciation, Depletion and Amortization
Segment Reporting, Disclosure of Entity's Reportable Segments [Abstract]
Unallocated corporate expenses	(0.2)	(0.6)
Selling, General and Administrative Expenses
Segment Reporting, Disclosure of Entity's Reportable Segments [Abstract]
Unallocated corporate expenses	(6.4)	(9.4)
Asset Impairment Charges and Other Expenses
Segment Reporting, Disclosure of Entity's Reportable Segments [Abstract]
Unallocated corporate expenses	(0.4)	(0.4)
Eliminations
Segment Reporting, Disclosure of Entity's Reportable Segments [Abstract]
Revenues	(0.2)	(0.3)
Cost of sales	(0.2)	(0.3)
Total
Segment Reporting, Disclosure of Entity's Reportable Segments [Abstract]
Segment operating income	(4.2)	(5.3)
Rocky Mountains | Operating Segments
Segment Reporting, Disclosure of Entity's Reportable Segments [Abstract]
Revenues	38.6	47.9
Cost of sales	33.8	37.7
Depreciation and amortization	5.9	6.8
Selling, general and administrative	1.9	1.9
Other segment items	0.8	1.7
Segment operating income	(3.8)	(0.2)
Southwest | Operating Segments
Segment Reporting, Disclosure of Entity's Reportable Segments [Abstract]
Revenues	53.7	65.4
Cost of sales	45.8	49.7
Depreciation and amortization	7.9	8.3
Selling, general and administrative	3.1	3.4
Other segment items	0.3	1.0
Segment operating income	(3.4)	3.0
Northeast /Mid-Con | Operating Segments
Segment Reporting, Disclosure of Entity's Reportable Segments [Abstract]
Revenues	52.6	41.0
Cost of sales	38.8	35.8
Depreciation and amortization	7.9	9.0
Selling, general and administrative	1.6	1.6
Other segment items	1.3	2.7
Segment operating income	$ 3.0	$ (8.1)