Contingencies (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013
Contingencies
Maximum liability under indemnity in connection with liquidation of an investment acquired	$ 23.0

The estimated maximum amount of possible loss from the contingency.

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

-Publisher FASB

-Name FASB Interpretation (FIN)

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-Paragraph 3

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 5

-Paragraph 9, 10, 11, 12

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 450

-SubTopic 20

-Section 50

-Paragraph 4

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 450

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-Section 50

-Paragraph 9

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-URI http://asc.fasb.org/extlink&oid=6952336&loc=d3e14557-108349

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