Benefit Obligations - Components of Net Periodic Benefit Cost (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 29, 2013	Sep. 30, 2012	Sep. 29, 2013	Sep. 30, 2012
Pension benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 120	$ 96	$ 362	$ 321
Interest cost	14,318	15,355	42,951	46,090
Expected return on plan assets	(16,578)	(17,024)	(49,734)	(51,077)
Net actuarial loss, prior service cost and transition asset amortization	4,785	3,592	14,354	10,754
Total benefit cost	2,645	2,019	7,933	6,088
Post-retirement benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	15	22	45	67
Interest cost	592	657	1,775	1,950
Expected return on plan assets	(888)	(953)	(2,665)	(2,859)
Net actuarial loss, prior service cost and transition asset amortization	363	523	1,091	1,513
Total benefit cost	$ 82	$ 249	$ 246	$ 671