3. Restricted Marketable Securities (Details) - Available For Sale - USD ($) $ in Thousands	6 Months Ended
Jun. 30, 2026	Dec. 31, 2025
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	$ 38,685	$ 52,562
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	0	713
Restricted marketable securities	214,315	217,172
Restricted Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	261,638	264,278
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	70	59
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	47,393	47,165
Restricted marketable securities	$ 214,315	217,172
Minimum [Member] \| Restricted Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Contractual maturities of Debt securities, Available-for-sale, range start (in years)	5 years
Maximum [Member] \| Restricted Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Contractual Maturities Of Debt securities, Available-for-sale, Range End (In Years)	13 years
U.S. debt [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost		10,000
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax		0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax		713
U.S. debt [Member] \| Restricted Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	$ 141,850	142,790
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	27,845	27,440
Restricted marketable securities	114,005	115,350
Foreign government obligations [Member] \| Restricted Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	65,549	67,091
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	12,228	12,935
Restricted marketable securities	53,321	54,156
Supranational debt [Member] \| Restricted Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	30,013	30,123
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	70	59
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	1,971	1,906
Restricted marketable securities	28,112	28,276
U.S. government obligations [Member] \| Restricted Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	24,226	24,274
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	5,349	4,884
Restricted marketable securities	$ 18,877	$ 19,390

Contractual Maturities Of Debt securities, Available-for-sale, Range End (In Years)

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Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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