Segments (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Aug. 31, 2019	Aug. 31, 2018	Aug. 31, 2019	Aug. 31, 2018	Feb. 28, 2019
Segment Reporting Information [Line Items]
Property, Plant and Equipment, Net	$ 214,098		$ 214,098		$ 210,227
Operations and assets by segment
Operating Income	22,207	$ 17,105	53,181	$ 40,801
Assets	1,120,117		1,120,117		1,088,570
Revenues	236,190	222,787	525,313	485,023
Energy
Operations and assets by segment
Operating Income	4,239	4,273	16,810	14,231
Assets	612,018		612,018		630,134
Revenues	111,347	106,515	278,316	253,501
Metal Coatings
Operations and assets by segment
Operating Income	28,673	22,076	58,065	47,260
Assets	489,305		489,305		440,090
Revenues	124,843	116,272	246,997	231,522
Corporate
Operations and assets by segment
Operating Income	(10,705)	(9,244)	(21,694)	(20,690)
Corporate
Operations and assets by segment
Assets	18,794		18,794		18,346
UNITED STATES
Segment Reporting Information [Line Items]
Property, Plant and Equipment, Net	192,537		192,537		189,281
Operations and assets by segment
Revenues	210,668	188,278	441,005	401,834
CANADA
Segment Reporting Information [Line Items]
Property, Plant and Equipment, Net	17,181		17,181		16,961
Other Countries [Member]
Segment Reporting Information [Line Items]
Property, Plant and Equipment, Net	4,380		4,380		$ 3,985
International [Member]
Operations and assets by segment
Revenues	$ 25,522	$ 34,509	$ 84,308	$ 83,189