Investments - Summary of Selected Financial Information for JCP Fund V (Details) - JCP Fund V - USD ($) $ in Thousands	3 Months Ended
Feb. 28, 2018	Dec. 31, 2017	Feb. 28, 2017	Dec. 31, 2016
Schedule of Equity Method Investments [Line Items]
Net gains (losses) from our investments in JCP Fund V	$ 6,800		$ (700)
Net increase (decrease) in net assets resulting from operations		$ 19,712		$ (2,294)

Amount of unrealized gain (loss) recognized in the income statement on unsold other securities.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3602-108585

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