Operating segments (Details) - USD ($) $ in Thousands	12 Months Ended
	Feb. 28, 2023	Feb. 28, 2022	Feb. 28, 2021
Operations and assets by segment
Sales	$ 1,323,649	$ 525,598	$ 480,574
Operating income (loss)	173,638	79,219	47,477
Loss on disposal of business	0	640	3,080
Depreciation	74,590	32,081	32,094
Expenditures for acquisitions, net of cash, and property, plant and equipment:	1,339,850	84,809	31,598
Assets:	2,221,479	1,133,027
Property, plant and equipment, net	498,503	193,358
Asset impairment charges	9,600
Corporate
Operations and assets by segment
Operating income (loss)	(61,824)	(49,539)	(40,819)
Depreciation	1,436	1,628	1,694
Expenditures for acquisitions, net of cash, and property, plant and equipment:	797	2,073	2,574
Assets:	59,572	46,266
United States
Operations and assets by segment
Sales	1,279,890	494,012	450,904
Property, plant and equipment, net	478,722	167,634
Canada
Operations and assets by segment
Sales	43,759	31,586	29,670
Property, plant and equipment, net	19,781	25,724
Metal Coatings | Operating Segments
Operations and assets by segment
Sales	636,982	525,598	461,693
Operating income (loss)	155,953	128,758	92,778
Loss on disposal of business			1,221
Depreciation	32,955	30,453	30,273
Expenditures for acquisitions, net of cash, and property, plant and equipment:	23,639	82,736	29,024
Assets:	588,337	578,885
Precoat Metals | Operating Segments
Operations and assets by segment
Sales	686,667	0	0
Operating income (loss)	79,509	0	0
Depreciation	40,199	0	0
Expenditures for acquisitions, net of cash, and property, plant and equipment:	1,315,414	0	0
Assets:	1,488,810	0
Infrastructure Solutions
Operations and assets by segment
Discontinued operations	0	507,876
Infrastructure Solutions | Operating Segments
Operations and assets by segment
Sales	0	0	18,881
Operating income (loss)	0	0	(4,482)
Loss on disposal of business			1,859
Depreciation	0	0	$ 127
Assets:	$ 84,760	$ 0