| Securities Owned Not Readily Marketable (Deprecated 2019-01-31) | en-US | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| Securities Owned Not Readily Marketable, Total (Deprecated 2019-01-31) | en-US | http://www.xbrl.org/2003/role/totalLabel | http://www.xbrl.org/2003/role/link |
| Aggregate carrying value of owned private equity or other securities for which a quoted market price is not readily determinable, the value of which has been determined by management based upon fair value methods, including pricing of similar securities and valuation techniques and is included in the schedule of financial condition or the balance sheet. | en-US | http://www.xbrl.org/2003/role/documentation | http://www.xbrl.org/2003/role/link |