Schedule of Net Periodic Pension (Benefit) Costs (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
Defined Benefit Plan Disclosure
Actuarial (gain) loss			$ (1,359)	$ 3,054
Defined Benefit Pension Plans
Defined Benefit Plan Disclosure
Service cost	852	643	1,686	1,357
Interest cost	3,281	4,125	6,575	8,185
Expected return on plan assets	(3,631)	(4,082)	(7,261)	(8,164)
Amortization of unrecognized prior service cost (benefit)	41	58	82	116
Actuarial (gain) loss	(1,123)	3,146	(1,047)	3,146
Total net periodic (benefit) cost	(580)	3,890	35	4,640
Post-Retirement Benefit Plans
Defined Benefit Plan Disclosure
Service cost	21	15	37	34
Interest cost	84	108	171	219
Amortization of unrecognized prior service cost (benefit)	(150)	(150)	(299)	(299)
Actuarial (gain) loss	(236)	(92)	(236)	(92)
Total net periodic (benefit) cost	$ (281)	$ (119)	$ (327)	$ (138)

Amount of gain (loss) related to change in benefit obligation resulting from changes in actuarial assumptions, for example, but not limited to, interest, mortality, employee turnover, salary, and temporary deviation from the substantive plan.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 30

-Glossary Gain or Loss

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- Definition

An amount calculated as a basis for determining the extent of delayed recognition of the effects of changes in the fair value of assets. The expected return on plan assets is determined based on the expected long-term rate of return on plan assets and the market-related value of plan assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

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Amount included in accumulated other comprehensive income (AOCI) related to prior service cost (credit) expected to be recognized as components of net periodic benefit cost for the fiscal year that follows the most recent annual statement of financial position.

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The increase in a defined benefit pension plan's projected benefit obligation or a defined benefit postretirement plan's accumulated postretirement benefit obligation due to the passage of time.

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The total amount of net periodic benefit cost for defined benefit plans for the period. Periodic benefit costs include the following components: service cost, interest cost, expected return on plan assets, gain (loss), prior service cost or credit, transition asset or obligation, and gain (loss) due to settlements or curtailments.

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The actuarial present value of benefits attributed by the pension benefit formula to services rendered by employees during the period. The portion of the expected postretirement benefit obligation attributed to employee service during the period. The service cost component is a portion of the benefit obligation and is unaffected by the funded status of the plan.

+ References

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