Accumulated Other Comprehensive Loss - Summary of Accumulated Other Comprehensive Loss (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jul. 01, 2012	Jun. 30, 2013	Jul. 01, 2012
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning, balance	$ (93,818)	$ (80,256)	$ (94,526)	$ (80,820)
Pre-tax Activity	1,164	934	2,329	1,864
Tax Effect	(456)	(367)	(913)	(733)
Ending, balance	(93,110)	(79,689)	(93,110)	(79,689)
Net Pension Activity [Member] | Actuarial Loss [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning, balance	(75,897)	(64,369)	(76,407)	(64,789)
Pre-tax Activity	838	694	1,676	1,387
Tax Effect	(329)	(273)	(657)	(546)
Ending, balance	(75,388)	(63,948)	(75,388)	(63,948)
Net Pension Activity [Member] | Prior Service Costs [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning, balance	(31)	(41)	(33)	(44)
Pre-tax Activity	4	5	8	10
Tax Effect	(1)	(2)	(3)	(4)
Ending, balance	(28)	(38)	(28)	(38)
Net Postretirement Benefits Activity [Member] | Actuarial Loss [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning, balance	(22,000)	(20,872)	(22,425)	(21,244)
Pre-tax Activity	700	612	1,400	1,225
Tax Effect	(274)	(241)	(549)	(482)
Ending, balance	(21,574)	(20,501)	(21,574)	(20,501)
Net Postretirement Benefits Activity [Member] | Prior Service Costs [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning, balance	4,104	5,021	4,334	5,251
Pre-tax Activity	(378)	(379)	(756)	(758)
Tax Effect	148	150	296	299
Ending, balance	3,874	4,792	3,874	4,792
Foreign Currency Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning, balance	6	5	5	6
Pre-tax Activity	0	2	1	0
Tax Effect	0	(1)	0	0
Ending, balance	$ 6	$ 6	$ 6	$ 6