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Investments - Cash Equivalents and Investments held at Fair Value (Detail) - USD ($) $ in Thousands | Sep. 30, 2022 | Dec. 31, 2021
--- | --- | ---
Schedule of Available-for-sale Securities [Line Items] |  |
Available-for-sale debt securities | $ 28,663 | $ 30,066
Fair Value, Measurements [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Total | 51,632 | 70,259
Fair Value, Measurements [Member] | Quoted Prices in Active Market for Identical Assets (Level 1) [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Total | 33,558 | 52,364
Fair Value, Measurements [Member] | Significant Other Observable Inputs (Level 2) [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Total | 18,074 | 17,895
Money Market Funds [Member] | Fair Value, Measurements [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Cash equivalents | 698 | 652
Money Market Funds [Member] | Fair Value, Measurements [Member] | Quoted Prices in Active Market for Identical Assets (Level 1) [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Cash equivalents | 698 | 652
Corporate Bonds [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Available-for-sale debt securities | 8,984 | 10,747
Corporate Bonds [Member] | Fair Value, Measurements [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Available-for-sale debt securities | 8,984 | 10,747
Corporate Bonds [Member] | Fair Value, Measurements [Member] | Significant Other Observable Inputs (Level 2) [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Available-for-sale debt securities | 8,984 | 10,747
Municipal Fixed-Rate Bonds [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Available-for-sale debt securities | 1,357 | 1,551
Municipal Fixed-Rate Bonds [Member] | Fair Value, Measurements [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Available-for-sale debt securities | 1,357 | 1,551
Municipal Fixed-Rate Bonds [Member] | Fair Value, Measurements [Member] | Significant Other Observable Inputs (Level 2) [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Available-for-sale debt securities | 1,357 | 1,551
Asset-Backed Bonds [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Available-for-sale debt securities | 2,911 | 322
Asset-Backed Bonds [Member] | Fair Value, Measurements [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Available-for-sale debt securities | 2,911 | 322
Asset-Backed Bonds [Member] | Fair Value, Measurements [Member] | Significant Other Observable Inputs (Level 2) [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Available-for-sale debt securities | 2,911 | 322
Mortgage/Agency-Backed Bonds [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Available-for-sale debt securities | 4,440 | 4,736
Mortgage/Agency-Backed Bonds [Member] | Fair Value, Measurements [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Available-for-sale debt securities | 4,440 | 4,736
Mortgage/Agency-Backed Bonds [Member] | Fair Value, Measurements [Member] | Significant Other Observable Inputs (Level 2) [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Available-for-sale debt securities | 4,440 | 4,736
U.S. Government Bonds [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Available-for-sale debt securities | 10,589 | 12,171
U.S. Government Bonds [Member] | Fair Value, Measurements [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Available-for-sale debt securities | 10,589 | 12,171
U.S. Government Bonds [Member] | Fair Value, Measurements [Member] | Quoted Prices in Active Market for Identical Assets (Level 1) [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Available-for-sale debt securities | 10,589 | 12,171
Foreign Government Securities / Bonds [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Available-for-sale debt securities | 382 | 539
Foreign Government Securities / Bonds [Member] | Fair Value, Measurements [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Available-for-sale debt securities | 382 | 539
Foreign Government Securities / Bonds [Member] | Fair Value, Measurements [Member] | Significant Other Observable Inputs (Level 2) [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Available-for-sale debt securities | 382 | 539
Marketable Equity Securities - Various Industries [Member] | Fair Value, Measurements [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Marketable equity securities | 760 | 12,606
Marketable Equity Securities - Various Industries [Member] | Fair Value, Measurements [Member] | Quoted Prices in Active Market for Identical Assets (Level 1) [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Marketable equity securities | 760 | 12,606
Deferred Compensation Plan Assets [Member] | Fair Value, Measurements [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Marketable equity securities | 21,511 | 26,935
Deferred Compensation Plan Assets [Member] | Fair Value, Measurements [Member] | Quoted Prices in Active Market for Identical Assets (Level 1) [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Marketable equity securities | $ 21,511 | $ 26,935

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