Benefit Obligations - Components of Net Periodic Benefit Cost (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Apr. 01, 2012
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 123	$ 109
Interest cost	14,270	15,252
Expected return on plan assets	(16,581)	(17,023)
Amortization of net actuarial loss, prior service cost and transition asset	4,669	3,469
Total benefit cost	2,481	1,807
Post-retirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	25	25
Interest cost	600	650
Expected return on plan assets	(875)	(1,050)
Amortization of net actuarial loss, prior service cost and transition asset	375	500
Total benefit cost	$ 125	$ 125