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Commitments and Contingencies - Product Warranty Accrual (Details) - USD ($)
Feb. 28, 2017
Feb. 29, 2016
Feb. 28, 2015
Feb. 28, 2014
Loss Contingencies [Line Items]        
Reserve for warranty $ 2,098,000 $ 2,915,000 $ 2,287,000 $ 1,338,000
Accrued warranty 2,098,000 $ 2,915,000    
Energy [Member]        
Loss Contingencies [Line Items]        
Letters of credit outstanding $ 23,100,000