This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. An amount representing an agreement for an unconditional promise by the maker to pay the Company (holder) a definite sum of money at a future date(s).

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 3

-Subparagraph b

-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 210.5-02.3(b))

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

Name:	us-gaap_NotesReceivableFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Summary of Significant Accounting Policies Schedule of Fair Value Measurements (Details) (USD $)	Jun. 30, 2012	Dec. 31, 2011
Estimate of Fair Value
Assets and Liabilities Measured at Fair Value
Notes receivable	$ 42,761,000	$ 43,787,000
Fixed Rate \| Estimate of Fair Value
Assets and Liabilities Measured at Fair Value
Indebtedness	1,800,000,000
Fixed Rate \| Carrying Amount
Assets and Liabilities Measured at Fair Value
Indebtedness	1,710,000,000
Variable Rate \| Estimate of Fair Value
Assets and Liabilities Measured at Fair Value
Indebtedness	129,900,000
Variable Rate \| Carrying Amount
Assets and Liabilities Measured at Fair Value
Indebtedness	$ 129,900,000