Restatement of Previously Issued Financial Statements - Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Aug. 31, 2017	Aug. 31, 2016	Aug. 31, 2017	Aug. 31, 2016
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net Income	$ 9,786	$ 10,159	$ 21,848	$ 32,348
Deferred income taxes			850	2,266
Inventories			(13,304)	(3,267)
Net change in billings related to costs and estimated earnings on uncompleted contracts			(14,197)	(1,874)
Other accrued liabilities and income taxes payable			(10,742)	(10,961)
Net cash (used in) provided by operating activities:			2,785	50,028
As Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net Income	8,329	10,023	21,569	31,086
Deferred income taxes			682	1,509
Inventories			(19,658)	(15,832)
Net change in billings related to costs and estimated earnings on uncompleted contracts			(16,487)	8,028
Other accrued liabilities and income taxes payable			(1,651)	(6,279)
Net cash (used in) provided by operating activities:			2,785	50,028
Correction
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net Income	$ 1,457	$ 136	279	1,262
Deferred income taxes			168	757
Inventories			6,354	12,565
Net change in billings related to costs and estimated earnings on uncompleted contracts			2,290	(9,902)
Other accrued liabilities and income taxes payable			(9,091)	(4,682)
Net cash (used in) provided by operating activities:			$ 0	$ 0