Retirement and Postretirement Benefit Plans (Details 1) (USD $) In Thousands, unless otherwise specified	Feb. 29, 2012	Feb. 28, 2011
Pension Plans [Member]
Summary of amounts recognized on the Consolidated Statement of Financial Position
Accrued compensation and benefits	$ (2,257)	$ (2,347)
Other liabilities	(75,746)	(59,932)
Net amount recognized	(78,003)	(62,279)
Amounts recognized in accumulated other comprehensive income:
Net actuarial loss (gain)	69,632	56,938
Net prior service cost (credit)	1,531	847
Net transition obligation	37	43
Accumulated other comprehensive loss (income)	71,200	57,828
Postretirement benefit plan [Member]
Summary of amounts recognized on the Consolidated Statement of Financial Position
Accrued compensation and benefits
Other liabilities	(24,781)	(24,101)
Net amount recognized	(24,781)	(24,101)
Amounts recognized in accumulated other comprehensive income:
Net actuarial loss (gain)	(3,081)	1,268
Net prior service cost (credit)	(8,855)	(11,316)
Net transition obligation
Accumulated other comprehensive loss (income)	$ (11,936)	$ (10,048)