Variable Interest Entities Variable Interest Entities (Details) - Variable Interest Entity, Primary Beneficiary $ in Thousands	Jun. 30, 2017 USD ($)
Variable Interest Entity [Line Items]
Consolidated VIE assets	$ 274,667
Consolidated VIE liabilities	158,374
Receivables from brokers, dealers and clearing organizations
Variable Interest Entity [Line Items]
Consolidated VIE assets	15,611
Financial instruments and other inventory positions owned and pledged as collateral
Variable Interest Entity [Line Items]
Consolidated VIE assets	154,852
Investments
Variable Interest Entity [Line Items]
Consolidated VIE assets	97,216
Other assets
Variable Interest Entity [Line Items]
Consolidated VIE assets	6,988
Short-term financing
Variable Interest Entity [Line Items]
Consolidated VIE liabilities	114,038
Payables to brokers, dealer and clearing organizations
Variable Interest Entity [Line Items]
Consolidated VIE liabilities	25,489
Financial instruments and other inventory positions sold, but not yet purchased
Variable Interest Entity [Line Items]
Consolidated VIE liabilities	10,933
Other liabilities and accrued expenses
Variable Interest Entity [Line Items]
Consolidated VIE liabilities	$ 7,914

The carrying amount of the consolidated Variable Interest Entity's assets included in the reporting entity's statement of financial position.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (bb)
-URI http://asc.fasb.org/extlink&oid=64801991&loc=d3e5710-111685

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