Note 3 - Investments and Restricted Investments (Tables)

6 Months Ended

Jun. 30, 2023

Notes Tables

Schedule of Available for Sale Securities, and Held to Maturity [Table Text Block]

	June 30, 2023
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
Investments, available for sale:
U.S. Treasuries	$	17,009	$	113	$	-		$	17,122
Total investments	$	17,009	$	113	$	-		$	17,122
Restricted investments, held-to-maturity:
U.S. Treasuries		114,171		761		(1,229	)		113,703
Total restricted investments	$	114,171	$	761	$	(1,229	)	$	113,703

	December 31, 2022
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
Investments, available for sale:
U.S. Treasuries	$	24,997	$	65	$	(167	)	$	24,895
Total investments	$	24,997	$	65	$	(167	)	$	24,895
Restricted investments, held-to-maturity:
U.S. Treasuries		114,648		299		(1,991	)		112,956
Total restricted investments	$	114,648	$	299	$	(1,991	)	$	112,956

Investments Classified by Contractual Maturity Date [Table Text Block]

	Investments		Restricted Investments
Due within one year	$	17,122	$	97,418
Due one year through five years		-		16,753
Total	$	17,122	$	114,171