Segments (Details) - USD ($)	3 Months Ended		6 Months Ended
	Aug. 31, 2016	Aug. 31, 2015	Aug. 31, 2016	Aug. 31, 2015	Feb. 29, 2016
Segment Reporting Information [Line Items]
Property, Plant and Equipment, Net	$ 224,001,000		$ 224,001,000		$ 226,333,000
Operations and assets by segment
Net Sales	195,045,000	$ 214,246,000	437,712,000	$ 443,134,000
Operating Income	14,889,000	26,419,000	49,397,000	59,304,000
Interest Expense	3,580,000	4,023,000	7,505,000	7,869,000
Gain (Loss) on Disposition of Property Plant Equipment	192,000	(25,000)	82,000	(449,000)
Other Nonoperating Income (Expense)	(68,000)	547,000	(190,000)	855,000
Income Before Income Taxes	11,185,000	21,874,000	42,000,000	51,029,000
Assets	991,734,000	982,399,164	991,734,000	982,399,164	982,010,000
Energy [Member]
Operations and assets by segment
Net Sales	97,601,000	110,777,000	235,703,000	247,780,000
Operating Income	8,195,000	9,005,000	26,948,000	26,961,000
Assets	543,140,895	527,769,472	543,140,895	527,769,472
Galvanizing Services [Member]
Operations and assets by segment
Net Sales	97,444,000	103,469,000	202,009,000	195,354,000
Operating Income	15,032,000	25,331,000	39,334,000	47,425,000
Assets	423,587,342	431,493,574	423,587,342	431,493,574
Corporate, Non-Segment [Member]
Operations and assets by segment
Operating Income	(8,338,000)	(7,917,000)	(16,885,000)	(15,082,000)
Corporate [Member]
Operations and assets by segment
Assets	25,006,000	23,136,118	25,006,000	23,136,118
UNITED STATES
Segment Reporting Information [Line Items]
Property, Plant and Equipment, Net	202,944,000		202,944,000		204,587,000
Operations and assets by segment
Net Sales	156,897,000	163,664,000	345,557,000	345,934,000
CANADA
Segment Reporting Information [Line Items]
Property, Plant and Equipment, Net	18,259,000		18,259,000		17,868,000
Other Countries [Member]
Segment Reporting Information [Line Items]
Property, Plant and Equipment, Net	2,798,000		2,798,000		$ 3,878,000
International [Member]
Operations and assets by segment
Net Sales	38,148,000	50,928,000	92,311,000	97,546,000
Geography Eliminations [Member]
Operations and assets by segment
Net Sales	$ 0	$ (346,000)	$ (156,000)	$ (346,000)