Fair Value Measurements (Assets And Liabilities Measured On Recurring Basis) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Fair Value Measurements [Line Items]
Total Assets	$ 26,291	$ 25,509
Total Liabilities	16,662	15,367
Quoted Prices In Active Markets For Identical Assets And Liabilities (Level1) [Member]
Fair Value Measurements [Line Items]
Total Assets	16,010	14,693
Total Liabilities	16,010	14,693
Significant Other Observable Inputs (Level 2) [Member]
Fair Value Measurements [Line Items]
Total Assets	10,281	10,816
Total Liabilities	652	674
Significant Unobservable Inputs (Level 3) [Member]
Fair Value Measurements [Line Items]
Total Assets
Total Liabilities
Grantor Trusts [Member]
Fair Value Measurements [Line Items]
Investments in grantor trusts	16,010	14,693
Deferred compensation plan obligations	16,010	14,693
Grantor Trusts [Member] | Quoted Prices In Active Markets For Identical Assets And Liabilities (Level1) [Member]
Fair Value Measurements [Line Items]
Investments in grantor trusts	16,010	14,693
Deferred compensation plan obligations	16,010	14,693
Grantor Trusts [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value Measurements [Line Items]
Investments in grantor trusts
Deferred compensation plan obligations
Interest Rate Contracts [Member]
Fair Value Measurements [Line Items]
Interest rate contracts, Assets	10,281	10,816
Interest rate contracts, Liabilities	652	674
Interest Rate Contracts [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value Measurements [Line Items]
Interest rate contracts, Assets	10,281	10,816
Interest rate contracts, Liabilities	652	674
Interest Rate Contracts [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value Measurements [Line Items]
Interest rate contracts, Assets
Interest rate contracts, Liabilities