Accumulated Other Comprehensive Loss (Accumulated Other Comprehensive Loss) (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Aug. 31, 2020	May 31, 2020	Aug. 31, 2019	May 31, 2019	Aug. 31, 2020	Aug. 31, 2019
Schedule of Accumulated Other Comprehensive Loss [Line Items]
Beginning balance		$ (150,071)			$ (150,071)
Other comprehensive loss before reclassifications					(18,229)
Amounts reclassified from accumulated other comprehensive loss					7,874
Other comprehensive income (loss), net of taxes	$ 4,979	(15,334)	$ (10,424)	$ (13,196)	(10,355)	$ (23,620)
Ending balance	(160,426)				(160,426)
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					1,456
Other comprehensive income (loss), net of taxes					1,456
Ending balance	(119,846)				(119,846)
Net Unrecognized Hedge Gains (Losses)
Schedule of Accumulated Other Comprehensive Loss [Line Items]
Beginning balance		$ (28,769)			(28,769)
Other comprehensive loss before reclassifications					(18,229)
Amounts reclassified from accumulated other comprehensive loss					6,418
Other comprehensive income (loss), net of taxes					(11,811)
Ending balance	$ (40,580)				$ (40,580)