Retirement and Postretirement Benefit Plans - Effect of One Percentage Point Change in Assumed Health Care Cost Trend Rate (Detail) (Postretirement Benefit Plan [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Feb. 28, 2015	Feb. 28, 2014
Postretirement Benefit Plan [Member]
Effect of one percentage point change in assumed health care cost trend rates
1% increase on service cost plus interest cost	$ 82	$ 80
1% increase on accumulated postretirement benefit obligation	2,083	2,462
1% decrease on service cost plus interest cost	(72)	(70)
1% decrease on accumulated postretirement benefit obligation	$ (1,798)	$ (2,139)