Retirement and Postretirement Benefit Plans - Summary of Fair Value of Defined Benefit Pension Plan Assets, Postretirement Benefit Plans (Detail) (Postretirement Benefit Plans [Member], USD $) In Thousands, unless otherwise specified	Feb. 28, 2013	Feb. 29, 2012	Feb. 28, 2011
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Fair value of defined benefit pension plan assets	$ 51,794	$ 57,563	$ 66,935
Quoted prices in active markets for identical assets (Level 1) [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Fair value of defined benefit pension plan assets	14,195	17,245
Significant other observable inputs (Level 2) [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Fair value of defined benefit pension plan assets	37,599	40,318
Short-term investments [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Fair value of defined benefit pension plan assets	1,706	849
Short-term investments [Member] | Quoted prices in active markets for identical assets (Level 1) [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Fair value of defined benefit pension plan assets
Short-term investments [Member] | Significant other observable inputs (Level 2) [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Fair value of defined benefit pension plan assets	1,706	849
Equity securities [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Fair value of defined benefit pension plan assets	14,195	17,245
Equity securities [Member] | Quoted prices in active markets for identical assets (Level 1) [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Fair value of defined benefit pension plan assets	14,195	17,245
Equity securities [Member] | Significant other observable inputs (Level 2) [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Fair value of defined benefit pension plan assets
Fixed-income funds [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Fair value of defined benefit pension plan assets	35,893	39,469
Fixed-income funds [Member] | Quoted prices in active markets for identical assets (Level 1) [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Fair value of defined benefit pension plan assets
Fixed-income funds [Member] | Significant other observable inputs (Level 2) [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Fair value of defined benefit pension plan assets	$ 35,893	$ 39,469