Components of Investment Income, Included in Other Income (Expense) in Accompanying Consolidated Statements of Operations (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended
Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Gain (Loss) on Investments [Line Items]
Gross realized gains from sale of trading securities	$ 58	$ 1	$ 139	$ 9
Gross realized (losses) from sale of trading securities		(20)	(1)	(20)
Dividend and interest income	11	9	31	27
Net unrealized holding gains (losses)	189	(568)	353	(418)
Net investment income (losses)	$ 258	$ (578)	$ 522	$ (402)

Income derived from investments in debt and equity securities and on cash and cash equivalents. Interest income represents earnings which reflect the time value of money or transactions in which the payments are for the use or forbearance of money. Dividend income represents a distribution of earnings to shareholders by investee companies.

+ References+ Details

The net change in the difference between the fair value and the carrying value, or in the comparative fair values, of trading securities held at each balance sheet date, that was included in earnings for the period. Trading securities are bought and held principally for the purpose of selling them in the near term (thus held for only a short period of time) and the change in net unrealized holding gain (loss) is included in earnings for the period.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Trading Securities

-URI http://asc.fasb.org/extlink&oid=6526789

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 21

-Subparagraph e

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 13

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 9

-Subparagraph (e)

-URI http://asc.fasb.org/extlink&oid=6872113&loc=d3e27357-111563

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 12

-Subparagraph a

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.7(c))

-URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688

Reference 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 35

-Paragraph 1

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=16383099&loc=d3e24584-111560

+ Details