Retirement Benefits (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	May 25, 2012	May 27, 2011
Defined Benefit Pension [Member]
Components of periodic benefit cost for defined benefit pension and postretirement benefit plans
Service cost	$ 334	$ 204
Interest cost	1,844	2,146
Expected return on plan assets	(1,613)	(1,672)
Amortization of prior service cost (credit)	61	59
Amortization of actuarial loss	816	569
Net periodic benefit cost	1,442	1,306
Postretirement benefit plan [Member]
Components of periodic benefit cost for defined benefit pension and postretirement benefit plans
Service cost	213	363
Interest cost	800	1,210
Expected return on plan assets	(840)	(1,098)
Amortization of prior service cost (credit)	(519)	(638)
Net periodic benefit cost	$ (346)	$ (163)