Fair Value Measurements (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Assets, Fair Value Disclosure [Abstract]
Marketable securities	$ 11,445	$ 21,322	$ 31,337
Deferred compensation fund	22,200	17,831
Quoted Prices in Active Markets (Level 1) [Member]
Assets, Fair Value Disclosure [Abstract]
Deferred compensation fund	18,608	13,717
Significant Other Observable Inputs (Level 2) [Member]
Assets, Fair Value Disclosure [Abstract]
Deferred compensation fund	3,592	4,114
Significant Unobservable Inputs (Level 3) [Member]
Assets, Fair Value Disclosure [Abstract]
Deferred compensation fund	0	0
Carrying Amount [Member]
Assets, Fair Value Disclosure [Abstract]
Deferred compensation fund	22,200	17,831
Total Fair Value [Member]
Assets, Fair Value Disclosure [Abstract]
Deferred compensation fund	22,200	17,831
Municipal Bonds [Member] | Quoted Prices in Active Markets (Level 1) [Member]
Assets, Fair Value Disclosure [Abstract]
Marketable securities	0	0
Municipal Bonds [Member] | Significant Other Observable Inputs (Level 2) [Member]
Assets, Fair Value Disclosure [Abstract]
Marketable securities	11,445	21,322
Municipal Bonds [Member] | Significant Unobservable Inputs (Level 3) [Member]
Assets, Fair Value Disclosure [Abstract]
Marketable securities	0	0
Municipal Bonds [Member] | Carrying Amount [Member]
Assets, Fair Value Disclosure [Abstract]
Marketable securities	11,445	21,322
Municipal Bonds [Member] | Total Fair Value [Member]
Assets, Fair Value Disclosure [Abstract]
Marketable securities	11,445	21,322
Money Market [Member] | Quoted Prices in Active Markets (Level 1) [Member]
Assets, Fair Value Disclosure [Abstract]
Deferred compensation fund	0	0
Money Market [Member] | Significant Other Observable Inputs (Level 2) [Member]
Assets, Fair Value Disclosure [Abstract]
Deferred compensation fund	3,592	4,114
Money Market [Member] | Significant Unobservable Inputs (Level 3) [Member]
Assets, Fair Value Disclosure [Abstract]
Deferred compensation fund	0	0
Money Market [Member] | Carrying Amount [Member]
Assets, Fair Value Disclosure [Abstract]
Deferred compensation fund	3,592	4,114
Money Market [Member] | Total Fair Value [Member]
Assets, Fair Value Disclosure [Abstract]
Deferred compensation fund	3,592	4,114
Balanced And Lifestyle [Member] | Quoted Prices in Active Markets (Level 1) [Member]
Assets, Fair Value Disclosure [Abstract]
Deferred compensation fund	8,174	6,311
Balanced And Lifestyle [Member] | Significant Other Observable Inputs (Level 2) [Member]
Assets, Fair Value Disclosure [Abstract]
Deferred compensation fund	0	0
Balanced And Lifestyle [Member] | Significant Unobservable Inputs (Level 3) [Member]
Assets, Fair Value Disclosure [Abstract]
Deferred compensation fund	0	0
Balanced And Lifestyle [Member] | Carrying Amount [Member]
Assets, Fair Value Disclosure [Abstract]
Deferred compensation fund	8,174	6,311
Balanced And Lifestyle [Member] | Total Fair Value [Member]
Assets, Fair Value Disclosure [Abstract]
Deferred compensation fund	8,174	6,311
Large Cap Growth [Member] | Quoted Prices in Active Markets (Level 1) [Member]
Assets, Fair Value Disclosure [Abstract]
Deferred compensation fund	4,292	2,724
Large Cap Growth [Member] | Significant Other Observable Inputs (Level 2) [Member]
Assets, Fair Value Disclosure [Abstract]
Deferred compensation fund	0	0
Large Cap Growth [Member] | Significant Unobservable Inputs (Level 3) [Member]
Assets, Fair Value Disclosure [Abstract]
Deferred compensation fund	0	0
Large Cap Growth [Member] | Carrying Amount [Member]
Assets, Fair Value Disclosure [Abstract]
Deferred compensation fund	4,292	2,724
Large Cap Growth [Member] | Total Fair Value [Member]
Assets, Fair Value Disclosure [Abstract]
Deferred compensation fund	4,292	2,724
Small Cap Value [Member] | Quoted Prices in Active Markets (Level 1) [Member]
Assets, Fair Value Disclosure [Abstract]
Deferred compensation fund	2,173	1,936
Small Cap Value [Member] | Significant Other Observable Inputs (Level 2) [Member]
Assets, Fair Value Disclosure [Abstract]
Deferred compensation fund	0	0
Small Cap Value [Member] | Significant Unobservable Inputs (Level 3) [Member]
Assets, Fair Value Disclosure [Abstract]
Deferred compensation fund	0	0
Small Cap Value [Member] | Carrying Amount [Member]
Assets, Fair Value Disclosure [Abstract]
Deferred compensation fund	2,173	1,936
Small Cap Value [Member] | Total Fair Value [Member]
Assets, Fair Value Disclosure [Abstract]
Deferred compensation fund	2,173	1,936
Fixed Income [Member] | Quoted Prices in Active Markets (Level 1) [Member]
Assets, Fair Value Disclosure [Abstract]
Deferred compensation fund	1,962	1,461
Fixed Income [Member] | Significant Other Observable Inputs (Level 2) [Member]
Assets, Fair Value Disclosure [Abstract]
Deferred compensation fund	0	0
Fixed Income [Member] | Significant Unobservable Inputs (Level 3) [Member]
Assets, Fair Value Disclosure [Abstract]
Deferred compensation fund	0	0
Fixed Income [Member] | Carrying Amount [Member]
Assets, Fair Value Disclosure [Abstract]
Deferred compensation fund	1,962	1,461
Fixed Income [Member] | Total Fair Value [Member]
Assets, Fair Value Disclosure [Abstract]
Deferred compensation fund	1,962	1,461
International [Member] | Quoted Prices in Active Markets (Level 1) [Member]
Assets, Fair Value Disclosure [Abstract]
Deferred compensation fund	1,079	785
International [Member] | Significant Other Observable Inputs (Level 2) [Member]
Assets, Fair Value Disclosure [Abstract]
Deferred compensation fund	0	0
International [Member] | Significant Unobservable Inputs (Level 3) [Member]
Assets, Fair Value Disclosure [Abstract]
Deferred compensation fund	0	0
International [Member] | Carrying Amount [Member]
Assets, Fair Value Disclosure [Abstract]
Deferred compensation fund	1,079	785
International [Member] | Total Fair Value [Member]
Assets, Fair Value Disclosure [Abstract]
Deferred compensation fund	1,079	785
Mid Cap Growth [Member] | Quoted Prices in Active Markets (Level 1) [Member]
Assets, Fair Value Disclosure [Abstract]
Deferred compensation fund	928	500
Mid Cap Growth [Member] | Significant Other Observable Inputs (Level 2) [Member]
Assets, Fair Value Disclosure [Abstract]
Deferred compensation fund	0	0
Mid Cap Growth [Member] | Significant Unobservable Inputs (Level 3) [Member]
Assets, Fair Value Disclosure [Abstract]
Deferred compensation fund	0	0
Mid Cap Growth [Member] | Carrying Amount [Member]
Assets, Fair Value Disclosure [Abstract]
Deferred compensation fund	928	500
Mid Cap Growth [Member] | Total Fair Value [Member]
Assets, Fair Value Disclosure [Abstract]
Deferred compensation fund	$ 928	$ 500