Long-Term Debt And Other Long-Term Liabilities (Long-Term Debt) (Details) (USD $)	0 Months Ended	3 Months Ended
Nov. 13, 2012	Jul. 24, 2012	May 18, 2011	Mar. 31, 2013	Dec. 31, 2012
Debt Instrument [Line Items]
Credit agreement with an average interest rate of 2.0% and 2.9% at March 31, 2013 and December 31, 2012, respectively				$ 70,000,000	$ 71,100,000
6.625% senior subordinated notes due 2021, net of unamortized discount of $4.6 million and $4.7 million at March 31, 2013 and December 31, 2012, respectively				645,365,000	645,259,000
Total long-term debt				715,365,000	716,359,000
Revolving credit facility interest rate				2.00%	2.90%
Interest percentage of senior subordinated notes	6.625%	6.625%	6.625%	6.625%
Debt instrument maturity date	May 15, 2021	May 15, 2021	May 15, 2021	May 15, 2021
Debt instrument, unamortized discount				$ 4,600,000	$ 4,700,000

Interest rate stated in the contractual debt agreement.

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- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

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-Publisher FASB

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 129

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- Definition

The amount of debt discount that was originally recognized at the issuance of the instrument that has yet to be amortized.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Accounting Principles Board Opinion (APB)

-Number 21

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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-Name FASB Staff Position (FSP)

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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- Definition

Amount borrowed under the credit facility as of the balance sheet date.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

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- Definition

The effective interest rate at the end of the reporting period.

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- Definition

Carrying amount of long-term debt, net of unamortized discount or premium, excluding amounts to be repaid within one year or the normal operating cycle, if longer (current maturities). Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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-Publisher FASB

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Including the current and noncurrent portions, carrying value as of the balance sheet date of Notes with the highest claim on the assets of the issuer in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle if longer). Senior note holders are paid off in full before any payments are made to junior note holders.

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