Retirement Benefits - Components of Periodic Benefit Cost for Corporation's Defined Benefit Pension and Postretirement Benefits Plans (Detail) - USD ($) $ in Thousands	3 Months Ended
	May 27, 2016	May 29, 2015
Defined Benefit Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 186	$ 159
Interest cost	1,593	1,558
Expected return on plan assets	(1,528)	(1,668)
Amortization of prior service cost (credit)	1	1
Amortization of actuarial loss (gain)	873	848
Defined benefit plan, net periodic benefit cost, total	1,125	898
Postretirement Benefits Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	86	125
Interest cost	528	525
Expected return on plan assets	(582)	(675)
Amortization of prior service cost (credit)	(175)	(175)
Amortization of actuarial loss (gain)	(367)	(300)
Defined benefit plan, net periodic benefit cost, total	$ (510)	$ (500)