Investments - Debt Securities and Other Investments, Included on Condensed Consolidated Balance Sheet and Recorded at Fair Value (Detail) - USD ($)	Sep. 30, 2023	Dec. 31, 2022
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		$ 9,671,000
Gross Unrealized Gains		9,000
Gross Unrealized Losses		(427,000)
Fair Value	$ 0	9,253,000
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		2,538,000
Gross Unrealized Gains		5,000
Gross Unrealized Losses		(81,000)
Fair Value		2,462,000
Municipal Fixed-Rate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		185,000
Gross Unrealized Losses		(5,000)
Fair Value		180,000
Asset-Backed Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		818,000
Gross Unrealized Gains		1,000
Gross Unrealized Losses		(24,000)
Fair Value		795,000
Mortgage/Agency-Backed Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		1,853,000
Gross Unrealized Losses		(105,000)
Fair Value		1,748,000
U.S. Government Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		3,870,000
Gross Unrealized Gains		3,000
Gross Unrealized Losses		(188,000)
Fair Value		3,685,000
Foreign Government Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		407,000
Gross Unrealized Losses		(24,000)
Fair Value		$ 383,000