Components of Net Periodic Benefit Expense (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 29, 2012	Jul. 01, 2011	Jun. 29, 2012	Jul. 01, 2011
Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost
Interest cost	467	527	933	1,055
Expected return on assets	(454)	(501)	(907)	(1,002)
Amortization of actuarial loss	170	108	341	216
Settlement charge	317	325	634	554
Net periodic benefit expense	500	459	1,001	823
Supplemental Executive Retirement Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost
Interest cost	52	64	103	128
Amortization of actuarial loss	14	9	29	18
Amortization of prior year service cost	(12)	(12)	(24)	(24)
Net periodic benefit expense	$ 54	$ 61	$ 108	$ 122