Interest rate stated in the contractual debt agreement.

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22(a)(1))

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

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-Name Accounting Standards Codification

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-SubTopic 30

-Section 45

-Paragraph 1A

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-Name Accounting Principles Board Opinion (APB)

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-Paragraph 16, 20

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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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Debt (Schedule Of Obligations Under Debt Arrangements) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Feb. 08, 2013	Dec. 31, 2012	Nov. 18, 2010
Debt Instrument [Line Items]
Senior secured credit facility	$ 271,000		$ 500,000
Senior unsecured notes	700,865		350,895
Senior unsecured notes, stated rate		5.75%		7.875%
Total long-term debt	971,865		850,895
7.875% Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Senior unsecured notes	350,865		350,895
Senior unsecured notes, stated rate	7.875%
Senior unsecured notes, unamortized premium	865		895
Five Point Seventy Five Percentage Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Senior unsecured notes	$ 350,000		$ 0
Senior unsecured notes, stated rate	575000.00%