Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI), classified as current.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount of gain (loss) recognized in other comprehensive income (OCI) from asset measured at fair value on recurring basis using unobservable input (level 3).

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Fair value of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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The total amount of investments that are intended to be held for an extended period of time (longer than one operating cycle).

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Amount of investment in debt security measured at fair value with change in fair value recognized in net income (trading) and investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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Amount of investment in debt security measured at fair value with change in fair value recognized in net income (trading).

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Unobservable input -book value multiple - maximum

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Unobservable input -book value multiple - weighted average

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FAIR VALUE MEASUREMENTS (Details)	3 Months Ended		6 Months Ended
FAIR VALUE MEASUREMENTS (Details)	Jun. 30, 2021 USD ($) $ / shares	Jun. 30, 2020 USD ($)	Jun. 30, 2021 USD ($) $ / shares	Jun. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)	Feb. 28, 2019 USD ($)	May 31, 2018 USD ($)
Investments in securities:
Investments in trading securities	$ 75,066,000		$ 75,066,000		$ 69,542,000
Total assets measured at fair value	79,264,000		79,264,000		73,069,000
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	3,872,000	$ 2,980,000	3,431,000	$ 3,975,000
Unrealized gains (losses) on private investments	215,000	334,000	656,000	(661,000)
Ending balance	$ 4,087,000	$ 3,314,000	$ 4,087,000	$ 3,314,000
Fair Value Inputs [Abstract] (Deprecated 2018-01-31)
Unobservable input -book value multiple - minimum \| $ / shares	1.38		1.38
Unobservable input -book value multiple - maximum	2.28		2.28
Unobservable input -book value multiple - weighted average	1.51		1.51
Long-term Investments	$ 4,455,000		$ 4,455,000		8,154,000	$ 300,000	$ 5,400,000
Level 1
Investments in securities:
Investments in trading securities	75,066,000		75,066,000		69,542,000
Total assets measured at fair value	75,066,000		75,066,000		69,542,000
Level 2
Investments in securities:
Investments in trading securities	0		0		0
Total assets measured at fair value	0		0		0
Level 3
Investments in securities:
Investments in trading securities	0		0		0
Total assets measured at fair value	4,087,000		4,087,000		3,431,000
Investments Measured at NAV
Investments in securities:
Investments in trading securities	0		0		0
Total assets measured at fair value	111,000		111,000		96,000
Private investment fund
Investments in securities:
Private	111,000		111,000		96,000
Private investment fund \| Level 1
Investments in securities:
Private	0		0		0
Private investment fund \| Level 2
Investments in securities:
Private	0		0		0
Private investment fund \| Level 3
Investments in securities:
Private	0		0		0
Private investment fund \| Investments Measured at NAV
Investments in securities:
Private	111,000		111,000		96,000
Private equity
Investments in securities:
Private	4,087,000		4,087,000		3,431,000
Private equity \| Level 1
Investments in securities:
Private	0		0		0
Private equity \| Level 2
Investments in securities:
Private	0		0		0
Private equity \| Level 3
Investments in securities:
Private	4,087,000		4,087,000		3,431,000
Private equity \| Investments Measured at NAV
Investments in securities:
Private	$ 0		$ 0		$ 0