Fair Value Measurements and Derivative Instruments (Available-for-sale Securities) (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized cost	$ 237,852	$ 247,866
Gross unrealized losses	(45,294)	(44,024)
Estimated fair value	192,558	203,842
Government and related securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized cost	30,636	35,048
Gross unrealized losses	(6,873)	(7,018)
Estimated fair value	23,763	28,030
Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized cost	63,126	65,008
Gross unrealized losses	(10,963)	(10,678)
Estimated fair value	52,163	54,330
Commingled fixed income securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized cost	1,799	1,788
Gross unrealized losses	(224)	(207)
Estimated fair value	1,575	1,581
Mortgage-backed / asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized cost	142,291	146,022
Gross unrealized losses	(27,234)	(26,121)
Estimated fair value	$ 115,057	$ 119,901