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Investments - Summary of Available for Sale Securities (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Total
Total, amortized cost	$ 11,735	$ 11,409
Total, gross unrealized gains	246	2,023
Total, gross unrealized losses	(80)	(63)
Total, estimated fair value	11,901	13,369
Mutual funds
Equity securities
Equity securities, amortized cost	6,352	6,001
Equity securities, gross unrealized gains	0	1,649
Equity securities, gross unrealized losses	(11)	0
Equity securities, estimated fair value	6,341	7,650
U.S. Government and agency securities
Available-for-sale securities
Available-for-sale securities, amortized cost	3,247	2,742
Available-for-sale securities, gross unrealized gains	10	0
Available-for-sale securities, gross unrealized losses	(4)	(4)
Available-for-sale securities, estimated fair value	3,253	2,738
Corporate bonds
Available-for-sale securities
Available-for-sale securities, amortized cost	2,033	2,559
Available-for-sale securities, gross unrealized gains	236	374
Available-for-sale securities, gross unrealized losses	(4)	(7)
Available-for-sale securities, estimated fair value	2,265	2,926
Asset-backed securities and collateralized mortgage obligations
Available-for-sale securities
Available-for-sale securities, amortized cost	103	107
Available-for-sale securities, gross unrealized gains	0	0
Available-for-sale securities, gross unrealized losses	(61)	(52)
Available-for-sale securities, estimated fair value	$ 42	$ 55

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