Investments in Marketable Securities and Unconsolidated Entities - Outstanding Borrowings of Unconsolidated Entities (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Sep. 30, 2015
Schedule of Equity Method Investments [Line Items]
Investments in unconsolidated entities	$ 9,361	$ 13,734
Unconsolidated Entities
Schedule of Equity Method Investments [Line Items]
Investments in unconsolidated entities	9,361	13,734
Total equity of unconsolidated entities	31,096	52,118
Total outstanding borrowings of unconsolidated entities	$ 16,146	$ 12,206