Investments in Securities and Fair Value (Schedule of Carrying Value and Fair Value of Financial Assets Disclosed) (Details) - USD ($) $ in Thousands	Sep. 30, 2025	Dec. 31, 2024
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	$ 22,759	$ 24,654
Accrued interest and dividends	1,470	1,469
Equity securities, estimated fair value	39,661	39,893
Money market funds and U.S. Treasury bills	88,085	59,101
Assets, fair value disclosure	151,975	125,117
Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	22,759	24,654
Accrued interest and dividends	1,470	1,469
Equity securities, estimated fair value	39,661	39,893
Money market funds and U.S. Treasury bills	88,085	59,101
Assets, fair value disclosure	151,975	125,117
Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	0	0
Accrued interest and dividends	0	0
Equity securities, estimated fair value	0	0
Money market funds and U.S. Treasury bills	0	0
Assets, fair value disclosure	0	0
Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	0	0
Accrued interest and dividends	0	0
Equity securities, estimated fair value	0	0
Money market funds and U.S. Treasury bills	0	0
Assets, fair value disclosure	$ 0	$ 0

Accrued dividends and interest, Estimated fair value

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- Definition

Fair value portion of asset recognized for present right to economic benefit.

+ References

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- Definition

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

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- Definition

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

+ References

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

+ References

No definition available.

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- Definition

Amount of investments including trading securities, available-for-sale securities, held-to-maturity securities, and short-term investments classified as other and current.

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