Noncontrolling Interests (Details) (USD $) In Thousands	9 Months Ended
Sep. 30, 2011	Sep. 30, 2010
Summary of redeemable noncontrolling interests
Redeemable noncontrolling interests, Beginning balance	$ 5,799	$ 4,369
Noncontrolling interest	660	582
Redemption value change	547
Redeemable noncontrolling interests	1,207	582
Formation of noncontrolling interests	510	1,390
Distribution to noncontrolling interests	(625)	(515)
Redeemable noncontrolling interests, Ending balance	$ 6,891	$ 5,826

As of the reporting date, the aggregate carrying amount of all noncontrolling interests which are redeemable by the (parent) entity (1) at a fixed or determinable price on a fixed or determinable date, (2) at the option of the holder of the noncontrolling interest, or (3) upon occurrence of an event that is not solely within the control of the (parent) entity. This item includes noncontrolling interest holder's ownership (or holders' ownership) regardless of the type of equity interest (common, preferred, other) including all potential organizational (legal) forms of the investee entity.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 480

-SubTopic 10

-Subparagraph (12)(c)

-Section S99

-Paragraph 3A

-URI http://asc.fasb.org/extlink&oid=6802392&loc=SL6540498-122764

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 480

-SubTopic 10

-Subparagraph 14

-Paragraph 3A

-Section S99

-URI http://asc.fasb.org/extlink&oid=6802392&loc=SL6540498-122764

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

-Publisher FASB

-Name Emerging Issues Task Force (EITF)

-Number D-98

-Paragraph 43

-Subparagraph b

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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.

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 480

-SubTopic 10

-Subparagraph 15

-Paragraph 3A

-Section S99

-URI http://asc.fasb.org/extlink&oid=6802392&loc=SL6540498-122764

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Emerging Issues Task Force (EITF)

-Number D-98

-Paragraph 43

-Subparagraph c

-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.

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Accounting Research Bulletin (ARB)

-Number 51

-Paragraph 27

-Appendix A

-Subparagraph c

Reference 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 480

-SubTopic 10

-Subparagraph (16)(c)

-Paragraph 3A

-Section S99

-URI http://asc.fasb.org/extlink&oid=6802392&loc=SL6540498-122764

+ Details