Fair Value Measurements (Financial Assets And Liabilities Carried At Fair Value) (Details) (USD $) In Thousands	Jul. 02, 2011		Dec. 31, 2010
Investments subtotal	$ 249,857		$ 211,045
Total assets at fair value	253,344		217,747
Total liabilities at fair value	7,089		3,427
Level 1 [Member]
Investments subtotal	246,943		205,448
Total assets at fair value	250,430		210,444
Total liabilities at fair value	5,320		3,427
Level 1 [Member] | U.S. Government And Agency Securities [Member]
Investments subtotal	27,651		21,318
Level 1 [Member] | Obligations Of Government-Sponsored Enterprises [Member]
Investments subtotal	3,836	[1]	5,785	[1]
Level 1 [Member] | State And Municipal Bonds [Member]
Investments subtotal	151,873		131,626
Level 1 [Member] | Corporate Securities [Member]
Investments subtotal	63,547		46,683
Level 1 [Member] | Other Investments [Member]
Investments subtotal	36		36
Level 1 [Member] | Forward Contracts [Member]
Total assets at fair value			1,569	[2]
Total liabilities at fair value	1,833	[2]
Level 1 [Member] | Money Market Investments Related To The Deferred Compensation Plan [Member]
Total assets at fair value	3,487		3,427
Level 1 [Member] | Liabilities Related To The Deferred Compensation Plan [Member]
Total liabilities at fair value	3,487		3,427
Level 2 [Member]
Total assets at fair value			1,706
Total liabilities at fair value	1,769
Level 2 [Member] | Forward Contracts [Member]
Total assets at fair value			1,706	[2]
Total liabilities at fair value	1,769	[2]
Level 3 [Member]
Investments subtotal	2,914		5,597
Total assets at fair value	2,914		5,597
Level 3 [Member] | State And Municipal Bonds [Member]
Investments subtotal			2,683
Level 3 [Member] | Corporate Securities [Member]
Investments subtotal	2,914		2,914
U.S. Government And Agency Securities [Member]
Investments subtotal	27,651		21,318
Obligations Of Government-Sponsored Enterprises [Member]
Investments subtotal	3,836	[1]	5,785	[1]
State And Municipal Bonds [Member]
Investments subtotal	151,873		134,309
Corporate Securities [Member]
Investments subtotal	66,461		49,597
Other Investments [Member]
Investments subtotal	36		36
Forward Contracts [Member]
Total assets at fair value			3,275	[2]
Total liabilities at fair value	3,602	[2]
Money Market Investments Related To The Deferred Compensation Plan [Member]
Total assets at fair value	3,487		3,427
Liabilities Related To The Deferred Compensation Plan [Member]
Total liabilities at fair value	$ 3,487		$ 3,427

[1] Includes investments in notes issued by the Federal Home Loan Mortgage Corporation, the Federal National Mortgage Association and the Federal Home Loan Bank.

[2] (2) The fair value of forward contracts are calculated as follows: a. Fair value of forward collar contract associated with forecasted sales hedges are calculated using the midpoint of ask and bid rates for similar contracts. b. Fair value of regular forward contracts associated with forecasted sales hedges are calculated using the period-end exchange rate adjusted for the discount rate (3 month LIBOR rate). c. Fair value of balance sheet hedges are calculated at the period end exchange rate adjusted for current forward points unless the hedge has been traded but not settled at period end. If this is the case, the fair value is calculated at the rate at which the hedge is being settled.