Subsidiary Guarantors - Senior Notes (Details) (USD $)	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011
Senior Notes (Details) [Abstract]
Carrying value of senior notes	$ 300,000,000	$ 300,000,000
Interest rate of senior notes	6.625%
Event of default for senior notes - failure of other debt payment at maturity in excess of this amount	50,000,000
Event of default for senior notes - not discharged, bonded or insured judgment in excess of this amount	$ 50,000,000
Senior notes are redeemable at a premium declining from this percentage	103.313%
Percentage of original aggregate principle amount of senior notes included in repurchase price at change of control	101.00%
Our ownership percentage of subsidiary guarantors of senior notes	100.00%

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.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.16)

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 16

-Article 9

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.16(a))

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Name:	us-gaap_SeniorNotes
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant