Accumulated Other Comprehensive Loss (Accumulated Other Comprehensive Loss) (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Nov. 30, 2020	Aug. 31, 2020	May 31, 2020	Nov. 30, 2019	Aug. 31, 2019	May 31, 2019	Nov. 30, 2020	Nov. 30, 2019
Schedule of Accumulated Other Comprehensive Loss [Line Items]
Beginning balance			$ (150,071)				$ (150,071)
Other comprehensive loss before reclassifications							(16,113)
Amounts reclassified from accumulated other comprehensive loss							13,260
Other comprehensive income (loss), net of taxes	$ 7,502	$ 4,979	(15,334)	$ 9,623	$ (10,424)	$ (13,196)	(2,853)	$ (13,997)
Ending balance	(152,924)						(152,924)
Net Unrecognized Actuarial Losses
Schedule of Accumulated Other Comprehensive Loss [Line Items]
Beginning balance			(121,302)				(121,302)
Other comprehensive loss before reclassifications							0
Amounts reclassified from accumulated other comprehensive loss							2,183
Other comprehensive income (loss), net of taxes							2,183
Ending balance	(119,119)						(119,119)
Net Unrecognized Hedge Gains (Losses)
Schedule of Accumulated Other Comprehensive Loss [Line Items]
Beginning balance			$ (28,769)				(28,769)
Other comprehensive loss before reclassifications							(16,113)
Amounts reclassified from accumulated other comprehensive loss							11,077
Other comprehensive income (loss), net of taxes							(5,036)
Ending balance	$ (33,805)						$ (33,805)