Fair Value Measurements (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Assets
Securities owned, at fair value:	$ 12,073	$ 7,436
Liabilities
Securities sold, not yet purchased, at fair value:	8,253	2,953
Recurring basis \| Total
Assets
Total Assets	19,071	10,164
Liabilities
Total Liabilities	8,253	2,953
Recurring basis \| Total \| Tax free money market mutual funds
Assets
Cash and cash equivalents:	33	33
Recurring basis \| Total \| Money market mutual funds
Assets
Cash and cash equivalents:	6,965	2,695
Recurring basis \| Total \| Corporate stocks-trading securities
Assets
Securities owned, at fair value:	8,160	2,894
Liabilities
Securities sold, not yet purchased, at fair value:	8,253	2,953
Recurring basis \| Total \| Mutual funds
Assets
Securities owned, at fair value:	3,913	4,542
Recurring basis \| Level 1
Assets
Total Assets	19,071	10,164
Liabilities
Total Liabilities	8,253	2,953
Recurring basis \| Level 1 \| Tax free money market mutual funds
Assets
Cash and cash equivalents:	33	33
Recurring basis \| Level 1 \| Money market mutual funds
Assets
Cash and cash equivalents:	6,965	2,695
Recurring basis \| Level 1 \| Corporate stocks-trading securities
Assets
Securities owned, at fair value:	8,160	2,894
Liabilities
Securities sold, not yet purchased, at fair value:	8,253	2,953
Recurring basis \| Level 1 \| Mutual funds
Assets
Securities owned, at fair value:	$ 3,913	$ 4,542

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (a)

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Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Cash

-URI http://asc.fasb.org/extlink&oid=6506951

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Cash Equivalents

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The aggregate fair value as of the balance sheet date of financial instruments and other positions owned by the entity including: (1) mortgages, mortgage-backed and asset backed securities; (2) US government and agency obligations; (3) state and municipal government obligations; (4) other sovereign government debt; (5) corporate obligations; (6) corporate equities; (7) principal investments; (8) derivative contracts; and (9) physical commodities. Includes both pledged and unpledged holdings.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 940

-SubTopic 320

-Section 45

-Paragraph 2

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Fair value of obligations incurred from short sales.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 940

-SubTopic 320

-Section 35

-Paragraph 1

-Subparagraph (b)

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Fair value of financial and nonfinancial obligations.

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