Stock-Based Compensation (Details Textual) (USD $)	3 Months Ended		6 Months Ended				6 Months Ended				6 Months Ended			6 Months Ended				6 Months Ended
	Jul. 01, 2012 EquityIncentivePlan	Jun. 30, 2011	Jul. 01, 2012 EquityIncentivePlan	Jun. 30, 2011	Jul. 01, 2012 Restricted Stock [Member]	Dec. 31, 2011 Restricted Stock [Member]	Jul. 01, 2012 Stock options [Member]	Dec. 31, 2011 Stock options [Member]	Jul. 01, 2012 ESPP [Member]	Jun. 30, 2011 Stock Appreciation Rights (SARs) [Member]	Jul. 01, 2012 Employees Stock Purchase Plan [Member]	Jun. 30, 2011 Employees Stock Purchase Plan [Member]	Jul. 01, 2012 Maximum [Member] ESPP [Member]	Jul. 01, 2012 Long-Term Plan [Member]	Jul. 01, 2012 Long-Term Plan [Member] Restricted Stock [Member]	Dec. 31, 2011 Long-Term Plan [Member] Restricted Stock [Member]	Jul. 01, 2012 Directors' Plan [Member]	Jul. 01, 2012 Directors' Plan [Member] Restricted Stock [Member]	Dec. 31, 2011 Directors' Plan [Member] Restricted Stock [Member]
Stock-Based Compensation (Textual) [Abstract]
Restricted stock awarded under stock compensation plans					122,612	122,208									100,112	98,208		22,500	24,000
Number of SARs issued under long term plan										40,000
Unearned compensation related to restricted stock awards																		$ 2,763,000	$ 2,427,000
Maximum Shares of Common Stock Issuable Under Stock Compensation Plans													750,000	500,000			400,000
Shares available for future grants									673,057					321,633			47,000
Period required for vested options in the directors' plans to become exercisable							6 months
Exercisable options under the Directors' Plan							100,000	104,000
Stock Based Compensation Plan Expiration Date														Apr. 08, 2020				Feb. 18, 2014
Term of outstanding restricted stock awards vest in equal annual increments					3 years
Restricted shares vested					(54,233)
Shares issued to redeem vested stock appreciation rights														3,957
Purchase price of common stock under the ESPP											90.00%
Issued shares under the ESPP					54,637						22,870	23,766
Recognized total stock-based compensation expense	800,000	1,100,000	1,200,000	1,500,000
Stock-Based Compensation (Additional Textual) [Abstract]
Number of active equity incentive plans under which stock awards can be issued	2		2
Period for exercising options under the directors' plan			10 years
Cost of purchase of shares			$ 272,000	$ 86,000
Purchases of shares due to elections			11,611	3,648