Cash, Cash Equivalents and Investments (Details 2) (USD $)	Oct. 02, 2011
Effective maturity dates of available-for-sale investments
Less than 1 Year	$ 142,409,000
1-2 Years	83,860,000
2-3 Years	53,692,000
3-4 Years	15,806,000
4 years	14,230,000
Fair Value, Total	309,997,000
Cash And Cash Equivalents (Additional Textual) [Abstract]
Contribution to limited partnership	19,886,000
Remaining amount of commitment in limited partnership	614,000
Municipal bonds [Member]
Effective maturity dates of available-for-sale investments
Less than 1 Year	49,626,000
1-2 Years	27,175,000
2-3 Years	19,999,000
3-4 Years	14,585,000
4 years	8,824,000
Fair Value, Total	120,209,000
Corporate bonds [Member]
Effective maturity dates of available-for-sale investments
Less than 1 Year	60,123,000
1-2 Years	36,032,000
2-3 Years	24,312,000
3-4 Years	1,221,000
4 years	3,641,000
Fair Value, Total	125,329,000
Agency bonds [Member]
Effective maturity dates of available-for-sale investments
Less than 1 Year	31,276,000
1-2 Years	11,499,000
2-3 Years	2,395,000
3-4 Years	0
4 years	0
Fair Value, Total	45,170,000
Sovereign debt [Member]
Effective maturity dates of available-for-sale investments
Less than 1 Year	0
1-2 Years	4,220,000
2-3 Years	6,986,000
3-4 Years	0
4 years	1,765,000
Fair Value, Total	12,971,000
Covered bonds [Member]
Effective maturity dates of available-for-sale investments
Less than 1 Year	1,384,000
1-2 Years	4,934,000
2-3 Years	0
3-4 Years	0
4 years	0
Fair Value, Total	$ 6,318,000

Available for sale securities debt maturities after four years fair value.

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