Investments - Cash Equivalents and Investments held at Fair Value (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale debt securities	$ 29,558	$ 30,066
Marketable equity securities	1,000	1,000
Fair Value, Measurements [Member]
Schedule of Available-for-sale Securities [Line Items]
Total	67,239	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	51,235	52,364
Fair Value, Measurements [Member] \| Significant Other Observable Inputs (Level 2) [Member]
Schedule of Available-for-sale Securities [Line Items]
Total	16,004	17,895
Money Market Funds [Member] \| Fair Value, Measurements [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash equivalents	457	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	457	652
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale debt securities	9,094	10,747
Corporate Bonds [Member] \| Fair Value, Measurements [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale debt securities	9,094	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	9,094	10,747
Municipal Fixed-Rate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale debt securities	1,647	1,551
Municipal Fixed-Rate Bonds [Member] \| Fair Value, Measurements [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale debt securities	1,647	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	1,647	1,551
Asset-Backed Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale debt securities	307	322
Asset-Backed Bonds [Member] \| Fair Value, Measurements [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale debt securities	307	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	307	322
Mortgage/Agency-Backed Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale debt securities	4,562	4,736
Mortgage/Agency-Backed Bonds [Member] \| Fair Value, Measurements [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale debt securities	4,562	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	4,562	4,736
U.S. Government Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale debt securities	13,554	12,171
U.S. Government Bonds [Member] \| Fair Value, Measurements [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale debt securities	13,554	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	13,554	12,171
Foreign Government Securities / Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale debt securities	394	539
Foreign Government Securities / Bonds [Member] \| Fair Value, Measurements [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale debt securities	394	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	394	539
Marketable Equity Securities - Various Industries [Member] \| Fair Value, Measurements [Member]
Schedule of Available-for-sale Securities [Line Items]
Marketable equity securities	11,143	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	11,143	12,606
Deferred Compensation Plan Assets [Member] \| Fair Value, Measurements [Member]
Schedule of Available-for-sale Securities [Line Items]
Marketable equity securities	26,081	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	$ 26,081	$ 26,935

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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