Operating Segments (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Nov. 30, 2025	May 31, 2025	Nov. 30, 2024	Nov. 30, 2025	Nov. 30, 2024	Feb. 28, 2025
Segment Reporting Information [Line Items]
Number of reportable segments not disclosed				Segment Information
Operations and assets by segment
Sales	$ 425,746		$ 403,654	$ 1,264,983	$ 1,225,869
Cost of sales	323,805		305,876	957,620	921,907
Gross margin	101,941		97,778	307,363	303,962
Selling, general and administrative	32,462		39,243	99,874	108,032
Operating income (loss)	69,479		58,535	207,489	195,930
Interest expense, net	(12,206)		(19,223)	(44,434)	(63,906)
Equity in earnings of unconsolidated subsidiaries	(1,437)		7,168	231,431	12,470
Other income (expense)	(276)		(763)	1,239	(142)
Income (loss) before income tax	55,560		45,717	395,725	144,352
Income taxes	14,485		12,114	94,396	35,728
Net income	41,075		33,603	301,329	108,624
Depreciation	22,777		20,633	66,976	61,383
Assets:	2,230,907			2,230,907		$ 2,227,101
Property, plant and equipment, net	604,091			604,091		592,941
Restructuring charges				3,744	0
Stock-based compensation				2,200
Distribution on investment in AVAIL joint venture				273,223	6,764
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	600			226,800
United States
Operations and assets by segment
Sales	413,214		392,503	1,228,606	1,194,212
Property, plant and equipment, net	584,963			584,963		574,332
Canada
Operations and assets by segment
Sales	12,532		11,151	36,377	31,657
Property, plant and equipment, net	19,128			19,128		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	18,471		24,889	58,668	65,699
Operating income (loss)	(18,471)		(24,889)	(58,668)	(65,699)
Interest expense, net	(12,206)		(19,223)	(44,434)	(63,906)
Equity in earnings of unconsolidated subsidiaries	0		0	0	0
Other income (expense)	(291)		(879)	1,285	(307)
Income (loss) before income tax	(30,968)		(44,991)	(101,817)	(129,912)
Income taxes	14,485		12,114	94,396	35,728
Net income	(45,453)		(57,105)	(196,213)	(165,640)
Depreciation	6,090		6,116	18,253	18,294
Assets:	18,197			18,197		24,250
Stock-based compensation				1,800
Metal Coatings | Operating Segments
Operations and assets by segment
Sales	194,998		168,599	572,197	516,750
Cost of sales	136,873		116,542	400,151	357,471
Gross margin	58,125		52,057	172,046	159,279
Selling, general and administrative	6,038		5,684	17,521	17,286
Operating income (loss)	52,087		46,373	154,525	141,993
Interest expense, net	0		0	0	0
Equity in earnings of unconsolidated subsidiaries	0		0	0	0
Other income (expense)	15		116	(46)	165
Income (loss) before income tax	52,102		46,489	154,479	142,158
Depreciation	7,070		6,614	20,560	19,955
Assets:	596,743			596,743		555,095
Restructuring charges				3,800
Stock-based compensation				400
Precoat Metals | Operating Segments
Operations and assets by segment
Sales	230,748		235,055	692,786	709,119
Cost of sales	186,932		189,334	557,469	564,436
Gross margin	43,816		45,721	135,317	144,683
Selling, general and administrative	7,932		8,641	23,559	24,980
Operating income (loss)	35,884		37,080	111,758	119,703
Interest expense, net	0		0	0	0
Equity in earnings of unconsolidated subsidiaries	0		0	0	0
Other income (expense)	0		0	0	0
Income (loss) before income tax	35,884		37,080	111,758	119,703
Depreciation	9,617		7,903	28,163	23,134
Assets:	1,557,397			1,557,397		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	21		29	126	67
Operating income (loss)	(21)		(29)	(126)	(67)
Interest expense, net	0		0	0	0
Equity in earnings of unconsolidated subsidiaries	(1,437)		7,168	231,431	12,470
Other income (expense)	0		0	0	0
Income (loss) before income tax	(1,458)		7,139	231,305	12,403
Depreciation	0		$ 0	0	$ 0
Assets:	$ 58,570			$ 58,570		$ 99,379