Summary of Significant Accounting Policies - Disaggregated Revenues (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Feb. 28, 2021	Nov. 30, 2020	Aug. 31, 2020	May 31, 2020	Feb. 29, 2020	Nov. 30, 2019	Aug. 31, 2019	May 31, 2019	Feb. 28, 2021	Feb. 29, 2020	Feb. 28, 2019
Disaggregation of Revenue [Line Items]
Sales	$ 195,629	$ 226,623	$ 203,372	$ 213,293	$ 245,365	$ 291,139	$ 236,190	$ 289,123	$ 838,917	$ 1,061,817	$ 927,087
Industrial
Disaggregation of Revenue [Line Items]
Sales									511,740	605,236	526,465
Transmission and distribution
Disaggregation of Revenue [Line Items]
Sales									209,729	254,836	212,433
Power generation
Disaggregation of Revenue [Line Items]
Sales									$ 117,448	$ 201,745	$ 188,189