Investments - Maturities (Details) $ in Thousands	Mar. 31, 2022 USD ($)
Adjusted Cost Basis
Due in one year or less	$ 370,511
Due after one year through five years	171,074
Due after five years through ten years	0
Total	541,585
Estimated Fair Value
Due in one year or less	369,566
Due after one year through five years	169,725
Due after five years through ten years	0
Total	$ 539,291