Accumulated Other Comprehensive Loss - Summary of Accumulated Other Comprehensive Loss (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 28, 2014	Sep. 29, 2013	Sep. 28, 2014	Sep. 29, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning, balance	$ (57,421)	$ (93,110)	$ (58,176)	$ (94,526)
Pre-tax Activity	638	1,163	1,870	3,492
Tax Effect	(247)	(449)	(724)	(1,362)
Ending, balance	(57,030)	(92,396)	(57,030)	(92,396)
Net Pension Activity [Member] | Actuarial Loss [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning, balance	(42,510)	(75,388)	(43,028)	(76,407)
Pre-tax Activity	450	837	1,294	2,513
Tax Effect	(173)	(323)	(499)	(980)
Ending, balance	(42,233)	(74,874)	(42,233)	(74,874)
Net Pension Activity [Member] | Prior Service Costs [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning, balance	(110)	(28)	(121)	(33)
Pre-tax Activity	9	4	27	12
Tax Effect	(4)	(2)	(11)	(5)
Ending, balance	(105)	(26)	(105)	(26)
Net Postretirement Benefits Activity [Member] | Actuarial Loss [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning, balance	(17,750)	(21,574)	(18,441)	(22,425)
Pre-tax Activity	562	700	1,688	2,100
Tax Effect	(218)	(270)	(653)	(819)
Ending, balance	(17,406)	(21,144)	(17,406)	(21,144)
Net Postretirement Benefits Activity [Member] | Prior Service Costs [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning, balance	2,945	3,874	3,410	4,334
Pre-tax Activity	(377)	(377)	(1,133)	(1,133)
Tax Effect	146	146	437	442
Ending, balance	2,714	3,643	2,714	3,643
Foreign Currency Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning, balance	4	6	4	5
Pre-tax Activity	(6)	(1)	(6)	0
Tax Effect	2	0	2	0
Ending, balance	$ 0	$ 5	$ 0	$ 5