Fair Value Measurements - Marketable Debt Securities (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2022	Dec. 31, 2021
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Amortized Cost	$ 108,778	$ 109,331
Gross Unrealized Gains	1,141	5,219
Gross Unrealized Losses	(2,748)	(154)
Estimated Fair Value	107,171	114,396
Credit Impairment Losses	0	0
Municipal bonds — available-for-sale
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Amortized Cost	108,778	109,331
Gross Unrealized Gains	1,141	5,219
Gross Unrealized Losses	(2,748)	(154)
Estimated Fair Value	107,171	114,396
Credit Impairment Losses	$ 0	$ 0