Summary of Fair Value Measurements of Trust's Assets (Detail) (USD $) In Thousands, unless otherwise specified	Feb. 28, 2013	Feb. 29, 2012
Defined Benefit Plan Disclosure [Line Items]
Plan assets, at fair value	$ 9,448	$ 8,517
Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Plan assets, at fair value	75	52
Mutual Funds-Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Plan assets, at fair value	5,886	5,528
Mutual Funds-Bonds
Defined Benefit Plan Disclosure [Line Items]
Plan assets, at fair value	3,487	2,937
Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure [Line Items]
Plan assets, at fair value	9,448	8,517
Fair Value, Inputs, Level 1 | Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Plan assets, at fair value	75	52
Fair Value, Inputs, Level 1 | Mutual Funds-Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Plan assets, at fair value	5,886	5,528
Fair Value, Inputs, Level 1 | Mutual Funds-Bonds
Defined Benefit Plan Disclosure [Line Items]
Plan assets, at fair value	$ 3,487	$ 2,937