Summary of Significant Accounting Policies Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Nov. 30, 2018	Nov. 30, 2017	Nov. 30, 2018	Nov. 30, 2017
Disaggregation of Revenue [Line Items]
Revenue, Net	$ 239,516	$ 208,158	$ 724,539	$ 609,770
Industrial [Member]
Disaggregation of Revenue [Line Items]
Revenue, Net	143,710	126,976	415,323	355,895
Trasmission & Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue, Net	35,927	45,795	162,033	130,134
Power Generation [Member]
Disaggregation of Revenue [Line Items]
Revenue, Net	$ 59,879	$ 35,387	$ 147,183	$ 123,741