Operating Segments (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Aug. 31, 2025	Aug. 31, 2024	Aug. 31, 2025	Aug. 31, 2024	May 31, 2025	Feb. 28, 2025
Operations and assets by segment
Sales	$ 417,275	$ 409,007	$ 839,237	$ 822,215
Cost of sales	315,983	305,493	633,815	616,031
Gross margin	101,292	103,514	205,422	206,184
Selling, general and administrative	32,831	35,868	67,412	68,789
Operating income (loss)	68,461	67,646	138,010	137,395
Interest expense, net	(13,665)	(21,909)	(32,228)	(44,683)
Equity in earnings of unconsolidated subsidiaries	59,345	1,478	232,868	5,302
Other income	188	417	1,515	621
Income (loss) before income tax	114,329	47,632	340,165	98,635
Income taxes	24,983	12,213	79,911	23,614
Net income	89,346	35,419	260,254	75,021
Depreciation	22,372	20,429	44,199	40,750
Assets:	2,225,983		2,225,983			$ 2,227,101
Property, plant and equipment, net	603,260		603,260			592,941
Restructuring charges			3,744	0
Stock-based compensation			2,200
Distribution on investment in AVAIL joint venture			273,223	5,155
AIS Joint Venture
Operations and assets by segment
Equity in earnings of unconsolidated subsidiaries	165,800
Equity Method Investment, Aggregate Cost					$ (107,400)
Distribution on investment in AVAIL joint venture	61,600		227,500
United States
Operations and assets by segment
Sales	404,398	398,658	815,393	801,709
Property, plant and equipment, net	583,876		583,876			574,332
Canada
Operations and assets by segment
Sales	12,877	10,349	23,844	20,506
Property, plant and equipment, net	19,384		19,384			18,609
Operating Segments
Operations and assets by segment
Stock-based compensation			2,200
Segment Reporting, Reconciling Item, Corporate Nonsegment [Member]
Operations and assets by segment
Sales	0	0	0	0
Cost of sales	0	0	0	0
Gross margin	0	0	0	0
Selling, general and administrative	19,740	22,563	40,197	40,811
Operating income (loss)	(19,740)	(22,563)	(40,197)	(40,811)
Interest expense, net	(13,665)	(21,909)	(32,228)	(44,683)
Equity in earnings of unconsolidated subsidiaries	0	0	0	0
Other income	186	424	1,575	572
Income (loss) before income tax	(33,219)	(44,048)	(70,850)	(84,922)
Income taxes	24,983	12,213	79,911	23,614
Net income	(58,202)	(56,261)	(150,761)	(108,536)
Depreciation	6,118	6,105	12,163	12,177
Assets:	19,616		19,616			24,250
Stock-based compensation			1,800
Metal Coatings | Operating Segments
Operations and assets by segment
Sales	189,984	171,500	377,199	348,152
Cost of sales	132,923	118,193	263,279	240,929
Gross margin	57,061	53,307	113,920	107,223
Selling, general and administrative	5,355	5,619	11,482	11,602
Operating income (loss)	51,706	47,688	102,438	95,621
Interest expense, net	0	0	0	0
Equity in earnings of unconsolidated subsidiaries	0	0	0	0
Other income	2	(7)	(60)	49
Income (loss) before income tax	51,708	47,681	102,378	95,670
Depreciation	6,830	6,685	13,490	13,341
Assets:	597,430		597,430			555,095
Restructuring charges			3,800
Stock-based compensation			400
Precoat Metals | Operating Segments
Operations and assets by segment
Sales	227,291	237,507	462,038	474,063
Cost of sales	183,060	187,300	370,536	375,102
Gross margin	44,231	50,207	91,502	98,961
Selling, general and administrative	7,710	7,677	15,627	16,338
Operating income (loss)	36,521	42,530	75,875	82,623
Interest expense, net	0	0	0	0
Equity in earnings of unconsolidated subsidiaries	0	0	0	0
Other income	0	0	0	0
Income (loss) before income tax	36,521	42,530	75,875	82,623
Depreciation	9,424	7,639	18,546	15,232
Assets:	1,548,718		1,548,718			1,548,377
Infrastructure Solutions [Member] | Operating Segments
Operations and assets by segment
Sales	0	0	0	0
Cost of sales	0	0	0	0
Gross margin	0	0	0	0
Selling, general and administrative	26	9	106	38
Operating income (loss)	(26)	(9)	(106)	(38)
Interest expense, net	0	0	0	0
Equity in earnings of unconsolidated subsidiaries	59,345	1,478	232,868	5,302
Other income	0	0	0	0
Income (loss) before income tax	59,319	1,469	232,762	5,264
Depreciation	0	$ 0	0	$ 0
Assets:	$ 60,219		$ 60,219			$ 99,379