Fair Value Measurements and Derivative Instruments (Available-for-sale Securities) (Details) - USD ($) $ in Thousands	Jun. 30, 2025	Dec. 31, 2024
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized cost	$ 184,580	$ 196,923
Gross unrealized gains	1
Gross unrealized losses	(34,087)	(38,944)
Estimated fair value	150,494	157,979
Government and related securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized cost	21,384	21,432
Gross unrealized gains	1
Gross unrealized losses	(6,222)	(5,688)
Estimated fair value	15,163	15,744
Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized cost	49,876	50,367
Gross unrealized gains	0
Gross unrealized losses	(6,577)	(8,208)
Estimated fair value	43,299	42,159
Commingled fixed income securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized cost	1,860	1,835
Gross unrealized gains	0
Gross unrealized losses	(194)	(223)
Estimated fair value	1,666	1,612
Mortgage-backed / asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized cost	111,460	123,289
Gross unrealized gains	0
Gross unrealized losses	(21,094)	(24,825)
Estimated fair value	$ 90,366	$ 98,464