Note 3 - Investments and Restricted Investments

6 Months Ended

Jun. 30, 2023

Notes to Financial Statements

Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block]

3. Investments and Restricted Investments

Investments of the Company's cash in various U.S. Treasury securities have been classified as available-for-sale and are carried at estimated fair value utilizing Level 1 inputs as determined based upon quoted market prices.

Pursuant to provisions within the Master Indenture of the Series 2021 Bonds, as defined in Note 8, the Company invests the funds held in the restricted trust bank accounts in various U.S. Treasury securities. Therefore, such investments are reported as “Restricted investments” in the accompanying consolidated balance sheets. Unrealized losses on certain of the Company's investments and restricted investments are primarily attributable to changes in interest rates. The Company does not believe the unrealized losses represent impairments because the unrealized losses are due to general market factors. The Company has not recognized an allowance for expected credit losses related to its investments or restricted investments as the Company has not identified any unrealized losses attributable to credit factors during the three and six months ended June 30, 2023. The held-to-maturity restricted investments are carried on the consolidated balance sheet at amortized cost. As of June 30, 2023, the Company has the ability and intent to hold these restricted investments until maturity, and as a result, the Company would not expect the value of these investments to decline significantly due to a sudden change in market interest rates. The fair value of the Company’s restricted investments is estimated utilizing Level 1 inputs including prices for U.S. Treasury securities with comparable maturities on active markets.

The following tables are summaries of the amortized cost, unrealized gains, unrealized losses, and fair value by investment type as of June 30, 2023 and December 31, 2022:

	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

The following table sets forth the maturity profile of the Company's investments and restricted investments as of June 30, 2023:

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