Marketable Securities (Available For Sale Securities) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 27, 2014	Dec. 28, 2013
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost, Total	$ 60,567	$ 56,401
Gross Unrealized Holding Gains	8,743	7,925
Gross Unrealized Holding Losses	(92)	(1,233)
Fair Value	69,218	63,093
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost, Total	1,198	970
Gross Unrealized Holding Gains	6,935	7,239
Fair Value	8,133	8,209
Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost, Total	59,369	55,431
Gross Unrealized Holding Gains	1,808	686
Gross Unrealized Holding Losses	(92)	(1,233)
Fair Value	$ 61,085	$ 54,884

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

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Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

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This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

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