Fair Value Measurements (Assets And Liabilities Measured On Recurring Basis) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Fair Value Measurements [Line Items]
Derivative assets	$ 12,844	$ 9,926
Fair Value, Measurements, Recurring [Member]
Fair Value Measurements [Line Items]
Investments, mutual funds	7,034
Total assets	37,635	25,956
Total liabilities	18,294	16,798
Fair Value, Measurements, Recurring [Member] \| Grantor Trusts [Member]
Fair Value Measurements [Line Items]
Investments, grantor trusts	17,757	16,030
Deferred compensation plan obligations	17,757	16,030
Fair Value, Measurements, Recurring [Member] \| Interest Rate Contracts [Member]
Fair Value Measurements [Line Items]
Derivative assets	12,844	9,926
Derivative liabilities	537	768
Fair Value, Measurements, Recurring [Member] \| Quoted Prices In Active Markets For Identical Assets And Liabilities (Level 1) [Member]
Fair Value Measurements [Line Items]
Investments, mutual funds	7,034
Total assets	24,791	16,030
Total liabilities	17,757	16,030
Fair Value, Measurements, Recurring [Member] \| Quoted Prices In Active Markets For Identical Assets And Liabilities (Level 1) [Member] \| Grantor Trusts [Member]
Fair Value Measurements [Line Items]
Investments, grantor trusts	17,757	16,030
Deferred compensation plan obligations	17,757	16,030
Fair Value, Measurements, Recurring [Member] \| Significant Other Observable Inputs (Level 2) [Member]
Fair Value Measurements [Line Items]
Total assets	12,844	9,926
Total liabilities	537	768
Fair Value, Measurements, Recurring [Member] \| Significant Other Observable Inputs (Level 2) [Member] \| Interest Rate Contracts [Member]
Fair Value Measurements [Line Items]
Derivative assets	12,844	9,926
Derivative liabilities	537	768
Fair Value, Measurements, Recurring [Member] \| Significant Unobservable Inputs (Level 3) [Member]
Fair Value Measurements [Line Items]
Total assets	0	0
Total liabilities	$ 0	$ 0

This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents Available-for-sale Securities which consist of all investments in certain debt and equity securities neither classified as trading or held-to-maturity securities. A debt security represents a creditor relationship with an enterprise. Debt securities include, among other items, US Treasury securities, US government securities, municipal securities, corporate bonds, convertible debt, commercial paper, and all securitized debt instruments. An equity security represents an ownership interest in an enterprise or the right to acquire or dispose of an ownership interest in an enterprise at fixed or determinable prices. Equity securities include, among other things, common stock, certain preferred stock, warrant rights, call options, and put options, but do not include convertible debt. An entity may opt to provide the reader with additional narrative text to better understand the nature of investments in debt and equity securities which are categorized as Available-for-sale.

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Fair values as of the balance sheet date of all assets resulting from contracts that meet the criteria of being accounted for as derivative instruments, net of the effects of master netting arrangements.

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- Definition

Derivative instrument obligations meeting the definition of a liability which the Company is a party to as of the balance sheet date.

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