Fair Value Measurements And Marketable Securities (Fair Value Measurements) (Details) (USD $)	Jun. 30, 2011	Dec. 31, 2010
Marketable securities	$ 40,782,000	$ 43,437,000
Equity securities - Deferred comp fund	13,462,000	12,080,000
Municipal Bonds [Member] | Carrying Amount [Member]
Marketable securities	40,782,000	43,437,000
Municipal Bonds [Member] | Total Fair Value [Member]
Marketable securities	40,782,000	43,437,000
Municipal Bonds [Member] | Significant Other Observable Inputs (Level 2) [Member]
Marketable securities	40,782,000	43,437,000
Money Market [Member] | Carrying Amount [Member]
Equity securities - Deferred comp fund	2,698,000	2,737,000
Money Market [Member] | Total Fair Value [Member]
Equity securities - Deferred comp fund	2,698,000	2,737,000
Money Market [Member] | Significant Other Observable Inputs (Level 2) [Member]
Equity securities - Deferred comp fund	2,698,000	2,737,000
Large Cap Value [Member] | Carrying Amount [Member]
Equity securities - Deferred comp fund	2,709,000	2,433,000
Large Cap Value [Member] | Total Fair Value [Member]
Equity securities - Deferred comp fund	2,709,000	2,433,000
Large Cap Value [Member] | Quoted Prices in Active Markets (Level 1) [Member]
Equity securities - Deferred comp fund	2,709,000	2,433,000
Large Cap Growth [Member] | Carrying Amount [Member]
Equity securities - Deferred comp fund	2,332,000	2,106,000
Large Cap Growth [Member] | Total Fair Value [Member]
Equity securities - Deferred comp fund	2,332,000	2,106,000
Large Cap Growth [Member] | Quoted Prices in Active Markets (Level 1) [Member]
Equity securities - Deferred comp fund	2,332,000	2,106,000
Small Cap Value [Member] | Carrying Amount [Member]
Equity securities - Deferred comp fund	1,376,000	1,152,000
Small Cap Value [Member] | Total Fair Value [Member]
Equity securities - Deferred comp fund	1,376,000	1,152,000
Small Cap Value [Member] | Quoted Prices in Active Markets (Level 1) [Member]
Equity securities - Deferred comp fund	1,376,000	1,152,000
Fixed Income [Member] | Carrying Amount [Member]
Equity securities - Deferred comp fund	1,213,000	987,000
Fixed Income [Member] | Total Fair Value [Member]
Equity securities - Deferred comp fund	1,213,000	987,000
Fixed Income [Member] | Quoted Prices in Active Markets (Level 1) [Member]
Equity securities - Deferred comp fund	1,213,000	987,000
Specialty [Member] | Carrying Amount [Member]
Equity securities - Deferred comp fund	833,000	712,000
Specialty [Member] | Total Fair Value [Member]
Equity securities - Deferred comp fund	833,000	712,000
Specialty [Member] | Quoted Prices in Active Markets (Level 1) [Member]
Equity securities - Deferred comp fund	833,000	712,000
International [Member] | Carrying Amount [Member]
Equity securities - Deferred comp fund	671,000	572,000
International [Member] | Total Fair Value [Member]
Equity securities - Deferred comp fund	671,000	572,000
International [Member] | Quoted Prices in Active Markets (Level 1) [Member]
Equity securities - Deferred comp fund	671,000	572,000
Balanced and Lifestyle [Member] | Carrying Amount [Member]
Equity securities - Deferred comp fund	666,000	566,000
Balanced and Lifestyle [Member] | Total Fair Value [Member]
Equity securities - Deferred comp fund	666,000	566,000
Balanced and Lifestyle [Member] | Quoted Prices in Active Markets (Level 1) [Member]
Equity securities - Deferred comp fund	666,000	566,000
Large Cap Blend [Member] | Carrying Amount [Member]
Equity securities - Deferred comp fund	507,000	444,000
Large Cap Blend [Member] | Total Fair Value [Member]
Equity securities - Deferred comp fund	507,000	444,000
Large Cap Blend [Member] | Quoted Prices in Active Markets (Level 1) [Member]
Equity securities - Deferred comp fund	507,000	444,000
Mid Cap Growth [Member] | Carrying Amount [Member]
Equity securities - Deferred comp fund	396,000	371,000
Mid Cap Growth [Member] | Total Fair Value [Member]
Equity securities - Deferred comp fund	396,000	371,000
Mid Cap Growth [Member] | Quoted Prices in Active Markets (Level 1) [Member]
Equity securities - Deferred comp fund	396,000	371,000
Small Cap Growth [Member] | Carrying Amount [Member]
Equity securities - Deferred comp fund	31,000
Small Cap Growth [Member] | Total Fair Value [Member]
Equity securities - Deferred comp fund	31,000
Small Cap Growth [Member] | Quoted Prices in Active Markets (Level 1) [Member]
Equity securities - Deferred comp fund	31,000
Mid Cap Value [Member] | Carrying Amount [Member]
Equity securities - Deferred comp fund	30,000
Mid Cap Value [Member] | Total Fair Value [Member]
Equity securities - Deferred comp fund	30,000
Mid Cap Value [Member] | Quoted Prices in Active Markets (Level 1) [Member]
Equity securities - Deferred comp fund	30,000
Carrying Amount [Member]
Equity securities - Deferred comp fund	13,462,000	12,080,000
Total Fair Value [Member]
Equity securities - Deferred comp fund	13,462,000	12,080,000
Quoted Prices in Active Markets (Level 1) [Member]
Equity securities - Deferred comp fund	10,764,000	9,343,000
Significant Other Observable Inputs (Level 2) [Member]
Equity securities - Deferred comp fund	$ 2,698,000	$ 2,737,000