Retirement Benefits - Components of Periodic Benefit Cost for Defined Benefit Pension and Postretirement Benefit Plans (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Nov. 23, 2012	Nov. 25, 2011	Nov. 23, 2012	Nov. 25, 2011
Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 386	$ 206	$ 1,053	$ 621
Interest cost	1,864	2,127	5,547	6,418
Expected return on plan assets	(1,632)	(1,655)	(4,854)	(4,998)
Amortization of prior service cost	61	61	184	184
Amortization of actuarial loss (gain)	1,005	557	2,636	1,684
Defined Benefit Plan, Net Periodic Benefit Cost, Total	1,684	1,296	4,566	3,909
Postretirement Benefit Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	88	363	513	1,088
Interest cost	531	1,210	2,131	3,630
Expected return on plan assets	(893)	(1,098)	(2,573)	(3,293)
Amortization of prior service cost	(519)	(638)	(1,557)	(1,913)
Amortization of actuarial loss (gain)	(339)		(339)
Defined Benefit Plan, Net Periodic Benefit Cost, Total	$ (1,132)	$ (163)	$ (1,825)	$ (488)