Segments (Details) (USD $)	3 Months Ended				9 Months Ended
	Nov. 30, 2014 segment		Nov. 30, 2013		Nov. 30, 2014		Nov. 30, 2013		Feb. 28, 2014	Aug. 31, 2013
Segment Reporting Information [Line Items]
Property, Plant and Equipment, Net	$ 196,157,668				$ 196,157,668				$ 197,639,229
Number of operating segments	2
Operations and assets by segment
Net Sales	224,833,465		197,755,332		634,375,500		570,712,180
Operating Income	32,927,777		25,247,660		83,731,667		79,002,220
General Corporate Expense	6,770,791	[1]	8,012,379	[1]	13,595,432	[1]	25,670,173	[1]
Interest Expense	4,099,062		4,614,787		12,531,398		13,743,886
Other (Income) Expense, Net	881,707	[2]	(7,370,167)	[2]	912,494	[2]	(11,851,674)	[2]
Total expenses	11,751,560		5,256,999		27,039,324		27,562,385
Income Before Income Taxes	28,678,376		27,911,999		71,087,092		77,130,974
Assets	981,339,357				981,339,357				953,253,035	989,175,461
Energy [Member]
Operations and assets by segment
Net Sales	130,052,065		112,035,365		361,132,711		312,634,887
Operating Income	16,729,216	[3]	11,852,775	[3]	29,422,249	[3]	35,633,812	[3]
Assets	549,968,132				549,968,132					551,704,437
Galvanizing Services [Member]
Operations and assets by segment
Net Sales	94,781,400		85,719,967		273,242,789		258,077,293
Operating Income	23,700,720	[3]	21,316,223	[3]	68,704,167	[3]	69,059,547	[3]
Assets	385,217,371				385,217,371					383,559,945
Operating Segments [Member]
Operations and assets by segment
Operating Income	40,429,936	[3]	33,168,998	[3]	98,126,416	[3]	104,693,359	[3]
Corporate [Member]
Operations and assets by segment
Assets	46,153,854				46,153,854					53,911,079
UNITED STATES
Segment Reporting Information [Line Items]
Property, Plant and Equipment, Net	171,208,819				171,208,819				171,726,976
Operations and assets by segment
Net Sales	177,801,000		164,005,000		516,127,000		460,735,000
CANADA
Segment Reporting Information [Line Items]
Property, Plant and Equipment, Net	22,302,748				22,302,748				23,779,595
Other Countries [Member]
Segment Reporting Information [Line Items]
Property, Plant and Equipment, Net	2,646,101				2,646,101				2,132,658
International [Member]
Operations and assets by segment
Net Sales	49,068,000		33,750,000		120,285,000		109,977,000
Geography Eliminations [Member]
Operations and assets by segment
Net Sales	$ (2,036,000)		$ 0		$ (2,036,000)		$ 0

[1] General Corporate Expense consists of selling, general and administrative expenses that are not specifically identifiable to a segment.

[2] Other expense, net includes gains or losses on sale of property, plant and equipment and other (income) expenses.

[3] Segment operating income consists of net sales, less cost of sales, specifically identifiable selling, general and administrative expenses, and other income and expense items that are specifically identifiable to a segment.