Operating Segments (Details) - USD ($) $ in Thousands	3 Months Ended
	May 31, 2025	May 31, 2024	Feb. 28, 2025
Operations and assets by segment
Sales	$ 421,962	$ 413,208
Cost of sales	317,832	310,538
Gross margin	104,130	102,670
Selling, general and administrative	34,581	32,921
Operating income (loss)	69,549	69,749
Interest expense, net	(18,563)	(22,774)
Equity in earnings of unconsolidated subsidiaries	173,523	3,824
Other income (expense)	1,327	204
Income (loss) before income tax	225,836	51,003
Income taxes	54,928	11,401
Net income	170,908	39,602
Depreciation	21,827	20,323
Assets:	2,159,185		$ 2,227,101
Property, plant and equipment, net	597,892		592,941
Restructuring charges	3,744	0
Stock-based compensation	2,200
AIS Joint Venture
Operations and assets by segment
Equity in earnings of unconsolidated subsidiaries	7,700
Equity Method Investment, Aggregate Cost	(107,400)
United States
Operations and assets by segment
Sales	410,995	403,051
Property, plant and equipment, net	578,505		574,332
Canada
Operations and assets by segment
Sales	10,967	10,157
Property, plant and equipment, net	19,387		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
Cost of sales	0	0
Gross margin	0	0
Selling, general and administrative	20,457	18,248
Operating income (loss)	(20,457)	(18,248)
Interest expense, net	(18,563)	(22,774)
Equity in earnings of unconsolidated subsidiaries	0	0
Other income (expense)	1,388	148
Income (loss) before income tax	(37,632)	(40,874)
Income taxes	54,928	11,401
Net income	(92,560)	(52,275)
Depreciation	6,044	6,073
Assets:	22,974		24,250
Stock-based compensation	1,800
Metal Coatings | Operating Segments
Operations and assets by segment
Sales	187,215	176,651
Cost of sales	130,356	122,735
Gross margin	56,859	53,916
Selling, general and administrative	6,127	5,984
Operating income (loss)	50,732	47,932
Interest expense, net	0	0
Equity in earnings of unconsolidated subsidiaries	0	0
Other income (expense)	(61)	56
Income (loss) before income tax	50,671	47,988
Depreciation	6,660	6,657
Assets:	569,103		555,095
Restructuring charges	3,800
Stock-based compensation	400
Precoat Metals | Operating Segments
Operations and assets by segment
Sales	234,747	236,557
Cost of sales	187,476	187,803
Gross margin	47,271	48,754
Selling, general and administrative	7,917	8,660
Operating income (loss)	39,354	40,094
Interest expense, net	0	0
Equity in earnings of unconsolidated subsidiaries	0	0
Other income (expense)	0	0
Income (loss) before income tax	39,354	40,094
Depreciation	9,123	7,593
Assets:	1,567,108		1,548,377
Infrastructure Solutions [Member] | Operating Segments
Operations and assets by segment
Sales	0	0
Cost of sales	0	0
Gross margin	0	0
Selling, general and administrative	80	29
Operating income (loss)	(80)	(29)
Interest expense, net	0	0
Equity in earnings of unconsolidated subsidiaries	173,523	3,824
Other income (expense)	0	0
Income (loss) before income tax	173,443	3,795
Depreciation	0	$ 0
Assets:	$ 0		$ 99,379