Commitments and Contingencies - Legal Proceedings and Other (Details)	12 Months Ended
Dec. 31, 2018 USD ($)
Real Estate Fund
Other [Abstract]
Committed total required invest funding	$ 25,000,000
Commitment agreement fundings	22,400,000
Real Estate Fund II
Other [Abstract]
Committed total required invest funding	28,000,000
Commitment agreement fundings	$ 15,300,000

Amount of the unrecorded obligation to transfer funds in the future for fixed or minimum amounts or quantities of goods or services at fixed or minimum prices (for example, as in take-or-pay contracts or throughput contracts).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 440
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=77896938&loc=d3e25336-109308

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