Investments - Fair Value, Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Marketable Securities [Line Items]
Estimated Fair Value	$ 252,221	$ 278,344
Obligations of U.S. Government and its agencies
Marketable Securities [Line Items]
Estimated Fair Value	251,240	277,358
Certificates of deposit
Marketable Securities [Line Items]
Estimated Fair Value	981	986
Quoted Price in Active Markets (Level 1)
Marketable Securities [Line Items]
Estimated Fair Value	0	0
Quoted Price in Active Markets (Level 1) | Obligations of U.S. Government and its agencies
Marketable Securities [Line Items]
Estimated Fair Value	0	0
Quoted Price in Active Markets (Level 1) | Certificates of deposit
Marketable Securities [Line Items]
Estimated Fair Value	0	0
Significant Other Observable Inputs (Level 2)
Marketable Securities [Line Items]
Estimated Fair Value	252,221	278,344
Significant Other Observable Inputs (Level 2) | Obligations of U.S. Government and its agencies
Marketable Securities [Line Items]
Estimated Fair Value	251,240	277,358
Significant Other Observable Inputs (Level 2) | Certificates of deposit
Marketable Securities [Line Items]
Estimated Fair Value	981	986
Significant Unobservable Inputs (Level 3)
Marketable Securities [Line Items]
Estimated Fair Value	0	0
Significant Unobservable Inputs (Level 3) | Obligations of U.S. Government and its agencies
Marketable Securities [Line Items]
Estimated Fair Value	0	0
Significant Unobservable Inputs (Level 3) | Certificates of deposit
Marketable Securities [Line Items]
Estimated Fair Value	$ 0	$ 0