Common Stock Transactions (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Common Stock Transactions - (Details) [Abstract]
Proceeds from Issuance of Common Stock, net	$ 0	$ 0	$ 121,450
Costs associated with the stock offering			$ 800

The cash inflow from the additional capital contribution to the entity.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 18

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 19

-Subparagraph a

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration