Capital and Reserve Requirement Information - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Brokers and Dealers [Abstract]
Aggregate indebtedness to net capital	15.0vrts_RatioOfIndebtednessToNetCapitalOne
Minimum net capital requirement based on aggregate indebtedness	$ 1.6us-gaap_MinimumNetCapitalRequired1	$ 1.9us-gaap_MinimumNetCapitalRequired1

Amount of minimum net capital required to be maintained to engage in securities transactions.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Rule 15c3

-Number 240

-Section 1

-Paragraph 1

-Subparagraph i

-Article 15c3

-Subsection a

Name:	us-gaap_MinimumNetCapitalRequired1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant