Segments (Details) $ in Thousands	3 Months Ended
	May. 31, 2015 USD ($) segment	May. 31, 2014 USD ($)	Feb. 28, 2015 USD ($)
Segment Reporting Information [Line Items]
Property, Plant and Equipment, Net	$ 195,830		$ 196,583
Number of operating segments | segment	2
Operations and assets by segment
Net Sales	$ 228,888	$ 216,126
Operating Income	32,885	27,847
Interest Expense	3,847	4,209
Gain (Loss) on Disposition of Property Plant Equipment	(424)	(27)
Other Nonoperating Income (Expense)	307	(31)
Income Before Income Taxes	29,155	23,696
Assets	991,160	983,539	936,914
Energy [Member]
Operations and assets by segment
Net Sales	137,003	130,521
Operating Income	17,956	13,657
Assets	556,308	559,341
Galvanizing Services [Member]
Operations and assets by segment
Net Sales	91,885	85,605
Operating Income	22,094	22,010
Assets	374,905	383,612
Corporate, Non-Segment [Member]
Operations and assets by segment
Operating Income	(7,165)	(7,820)
Corporate [Member]
Operations and assets by segment
Assets	59,947	40,586
UNITED STATES
Segment Reporting Information [Line Items]
Property, Plant and Equipment, Net	173,562		173,712
Operations and assets by segment
Net Sales	182,270	176,439
CANADA
Segment Reporting Information [Line Items]
Property, Plant and Equipment, Net	19,931		20,289
Other Countries [Member]
Segment Reporting Information [Line Items]
Property, Plant and Equipment, Net	2,337		$ 2,582
International [Member]
Operations and assets by segment
Net Sales	$ 46,618	$ 39,687