CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Net income	$ 128,198	$ 104,151	$ 97,866
Foreign currency translation adjustment	(48,955)	(15,322)	5,318
Unrealized gains on marketable securities	0	0	921
Prior service cost and (losses) gains for the period	(42,236)	19,293	(8,634)
Amortization of prior service costs and net gains and losses	(1,234)	(3,017)	(2,772)
Comprehensive income, net of income taxes	48,138	103,334	99,920
Less: Comprehensive income related to noncontrolling interests	1,044	1,752	615
Comprehensive income attributable to common shareholders	47,094us-gaap_ComprehensiveIncomeNetOfTax	101,582us-gaap_ComprehensiveIncomeNetOfTax	99,305us-gaap_ComprehensiveIncomeNetOfTax
Accumulated Other Comprehensive Income (Loss) [Member]
Comprehensive income, before income taxes	38,241	111,139	98,243
Noncontrolling Interest [Member]
Income tax expense (benefit) related to items of other comprehensive income (Note 8)	$ (9,897)	$ 7,805	$ (1,677)

Comprehensive (Income) Loss, Net of Tax, Attributable to Noncontrolling Interest and Redeemable Noncontrolling Interest

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Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest and Redeemable Noncontrolling Interest

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Net Income (Loss), Including Portion Attributable to Noncontrolling Interest and Redeemable Noncontrolling Interest

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Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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Amount after tax and reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature.

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Amount after tax of other comprehensive (income) loss attributable to noncontrolling interests.

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Amount after tax of other comprehensive income (loss) attributable to parent entity.

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Amount after tax and reclassification adjustments, of (increase) decrease in accumulated other comprehensive (income) loss related to pension and other postretirement defined benefit plans.

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Amount before tax of reclassification adjustment from accumulated other comprehensive income (loss) for actuarial gain (loss) related to pension and other postretirement benefit plans.

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Amount after tax, before reclassification adjustments, of unrealized holding gain (loss) on available-for-sale securities.

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