Computation of Earnings Per Share (Details) (USD $)	3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended	6 Months Ended
	Jun. 29, 2012	Jul. 01, 2011	Jun. 29, 2012	Jul. 01, 2011	Jun. 29, 2012 Equity awards granted to employees [Member]	Jul. 01, 2011 Equity awards granted to employees [Member]	Jun. 29, 2012 Equity awards granted to employees [Member]	Jul. 01, 2011 Equity awards granted to employees [Member]	Jun. 29, 2012 Warrant [Member]	Jun. 29, 2012 Warrant [Member]	Jul. 01, 2011 Warrant [Member]	Nov. 30, 2010 Convertible Debt [Member] Convertible Debt Securities [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount					372,486	156,230	358,208	268,207	3,396,016	3,394,841	3,386,739
Net earnings	$ 16,479,000	$ 14,027,000	$ 25,882,000	$ 28,219,000
Weighted Average Number of Shares Outstanding, Basic	26,390,000	26,286,000	26,342,000	26,206,000
Earnings Per Share, Basic	$ 0.62	$ 0.53	$ 0.98	$ 1.08
Incremental Common Shares Attributable to Share-based Payment Arrangements	144,000	262,000	156,000	245,000
Weighted average shares issuable on exercise of convertible notes	0	125,000	0	63,000
Weighted Average Number of Shares Outstanding, Diluted	26,534,000	26,673,000	26,498,000	26,514,000
Earnings Per Share, Diluted	$ 0.62	$ 0.53	$ 0.98	$ 1.06
Convertible Notes, Face Amount												$ 115,000,000