Retirement and Postretirement Benefit Plans - Summary of Fair Value of Defined Benefit Pension Plan Assets, Postretirement Benefit Plans (Detail) (Postretirement Benefit Plan [Member], USD $) In Thousands, unless otherwise specified	Feb. 28, 2015	Feb. 28, 2014	Feb. 28, 2013
Defined Benefit Plan Disclosure [Line Items]
Fair value of defined benefit pension plan assets	$ 45,600	$ 48,757	$ 51,794
Short-term investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of defined benefit pension plan assets	1,192	1,312
Equity securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of defined benefit pension plan assets	12,133	12,968
Fixed income securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of defined benefit pension plan assets	32,275	34,477
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of defined benefit pension plan assets	12,133	12,968
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Equity securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of defined benefit pension plan assets	12,133	12,968
Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of defined benefit pension plan assets	33,467	35,789
Level 2 [Member] | Short-term investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of defined benefit pension plan assets	1,192	1,312
Level 2 [Member] | Fixed income securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of defined benefit pension plan assets	$ 32,275	$ 34,477