Annual report pursuant to Section 13 and 15(d)

Assets Dispositions - Additional Information (Detail)

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Assets Dispositions - Additional Information (Detail) - USD ($)
$ in Thousands
3 Months Ended 12 Months Ended
Jun. 24, 2019
Mar. 31, 2019
Mar. 31, 2020
Mar. 31, 2019
Mar. 31, 2018
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]          
Impairment loss   $ 6,449   $ 6,449 $ 14,816
Proceeds from sale of subsidiary     $ 602    
Loss on sale of Energy Steel & Supply Co.     181    
Westinghouse Electric Company [Member]          
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]          
Bad debt charge     98    
Inventory write down     338    
Energy Steel [Member]          
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]          
Proceeds from sale of subsidiary $ 602        
Working capital adjustment determination period 90 days        
Net accounts receivable $ 202        
Loss on sale of Energy Steel & Supply Co.     $ 181