Subsequent Events (Details)	Apr. 20, 2017 $ / shares
Agreement and Plan of Merger with Virtu Financial, Inc. \| Subsequent Event
Subsequent Event [Line Items]
Cash exercise price of right (in usd per share)	$ 20.00

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

No definition available.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration