Fair Value of Assets and Liabilities (Details Textual)	Mar. 31, 2013
Fair Value of Assets and Liabilities (Textual) [Abstract]
Notes bear interest at a rate	7.75%
Senior Note Due 2017
Fair Value of Assets and Liabilities (Textual) [Abstract]
Notes bear interest at a rate	7.75%
Senior Notes Due 2021
Fair Value of Assets and Liabilities (Textual) [Abstract]
Notes bear interest at a rate	6.625%
Senior Notes Due 2023
Fair Value of Assets and Liabilities (Textual) [Abstract]
Notes bear interest at a rate	5.125%

Interest rate stated in the contractual debt agreement.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

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

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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