Retirement Benefits - Components of Periodic Benefit Cost for Corporation's Defined Benefit Pension and Postretirement Benefits Plans (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Aug. 28, 2015	Aug. 29, 2014	Aug. 28, 2015	Aug. 29, 2014
Defined Benefit Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 159	$ 145	$ 318	$ 289
Interest cost	1,550	1,846	3,108	3,683
Expected return on plan assets	(1,659)	(1,628)	(3,327)	(3,251)
Amortization of prior service cost (credit)	1	1	2	2
Amortization of actuarial loss (gain)	846	720	1,694	1,426
Defined benefit plan, net periodic benefit cost, total	897	1,084	1,795	2,149
Postretirement Benefits Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	125	100	250	200
Interest cost	525	675	1,050	1,350
Expected return on plan assets	(675)	(700)	(1,350)	(1,400)
Amortization of prior service cost (credit)	(175)	(325)	(350)	(650)
Amortization of actuarial loss (gain)	(300)	(225)	(600)	(450)
Defined benefit plan, net periodic benefit cost, total	$ (500)	$ (475)	$ (1,000)	$ (950)