Investments - JCP Fund V - Narrative (Details) - USD ($) $ in Thousands	6 Months Ended
	May 31, 2018	Nov. 30, 2017
Schedule of Equity Method Investments [Line Items]
Financial instruments owned, at fair value	$ 15,705,657	$ 14,193,352
JCP Fund V
Schedule of Equity Method Investments [Line Items]
Financial instruments owned, at fair value	29,500	19,600
Unfunded portion of equity commitment to subsidiary	$ 10,000	10,100
Percent of financial information presented	100.00%
Ownership percentage	35.20%
Maximum | JCP Fund V
Schedule of Equity Method Investments [Line Items]
Total committed equity capitalization	$ 85,000	$ 85,000