BUSINESS SEGMENTS - Schedule Of Net Sales By Product Group (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Product and Service, Revenue [Line Items]
Total	$ 209,764	$ 172,963	$ 390,754	$ 332,133
Aluminum Extrusions
Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Product and Service, Revenue [Line Items]
Total	184,129	148,367	343,586	281,999
High Performance Films
Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Product and Service, Revenue [Line Items]
Total	25,635	24,596	47,168	50,134
Nonresidential building & construction \| Aluminum Extrusions
Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Product and Service, Revenue [Line Items]
Total	91,043	81,625	172,231	149,223
Consumer durables \| Aluminum Extrusions
Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Product and Service, Revenue [Line Items]
Total	14,314	12,751	27,636	24,418
Automotive \| Aluminum Extrusions
Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Product and Service, Revenue [Line Items]
Total	13,532	11,069	25,124	22,067
Residential building & construction \| Aluminum Extrusions
Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Product and Service, Revenue [Line Items]
Total	14,809	10,025	26,749	19,023
Electrical \| Aluminum Extrusions
Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Product and Service, Revenue [Line Items]
Total	19,046	12,522	30,026	27,863
Machinery & equipment \| Aluminum Extrusions
Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Product and Service, Revenue [Line Items]
Total	25,758	15,998	51,229	31,281
Distribution \| Aluminum Extrusions
Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Product and Service, Revenue [Line Items]
Total	5,627	4,377	10,591	8,124
Subtotal \| Aluminum Extrusions
Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Product and Service, Revenue [Line Items]
Total	184,129	148,367	343,586	281,999
Surface protection films \| High Performance Films
Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Product and Service, Revenue [Line Items]
Total	17,972	16,741	32,171	35,512
Advanced packaging \| High Performance Films
Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Product and Service, Revenue [Line Items]
Total	7,663	7,855	14,997	14,622
Subtotal \| High Performance Films
Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Product and Service, Revenue [Line Items]
Total	$ 25,635	$ 24,596	$ 47,168	$ 50,134