Marketable Securities (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Schedule of Investments [Line Items]
Net unrealized holding gains (losses)	$ (302)	$ 1,193
Unrealized holding gains (losses) during the period, income tax expense (benefit)	(43)	703
Available-for-sale securities, gross realized gains	489	1,401	$ 1,236
Available-for-sale securities, gross realized losses	729	448	772
Investment funds sponsored by LSV	4,039	4,523
Securities owned	21,235	21,175
Investment funds sponsored by LSV [Member]
Schedule of Investments [Line Items]
Investment funds sponsored by LSV	4,039	4,523
Change in fair value of investment funds sponsored by LSV	$ (389)	$ (326)	$ 143

Accumulated Other Comprehensive Income (Loss) Available For Sale Securities Adjustment Tax

No definition available.

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- Definition

Accumulated appreciation or loss, net of tax, in value of the total of available-for-sale securities at the end of an accounting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 14A
-URI http://asc.fasb.org/extlink&oid=36458714&loc=SL7669686-108580

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-Publisher FASB
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-Topic 220
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- Definition

This item represents the gross profit realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
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-Section 50
-Paragraph 9
-Subparagraph (a)
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This item represents the gross loss realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities.

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The fair value as of the balance sheet date of firm holdings in debt obligations issued by the US government including short-term Treasury bills, medium-term Treasury notes, and long-term Treasury bonds, as well as debt issued by agencies. Includes both pledged (to counterparties as collateral for financing transactions) 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
-URI http://asc.fasb.org/extlink&oid=35711157&loc=d3e42546-110969

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- Definition

All other debt and equity financial instruments, which aren't categorized as available-for-sale, or held-to-maturity and which are not otherwise listed in the existing taxonomy, intended to be held longer than one year from the balance sheet date or the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.12)
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- Definition

The net realized gains or losses on investments during the period, not including gains or losses on securities separately or otherwise categorized as trading, available-for-sale, or held-to-maturity.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04.3(a))
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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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