Summary of Significant Accounting Policies - Company's Condensed Consolidated Statement of Comprehensive Income (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended
		Mar. 31, 2023	Mar. 31, 2022
Accounting Policies [Line Items]
Premium deficiency reserve benefit		$ (1,810)	$ (27,476)
Total operating expenses		600,381	961,860
Loss from operations		(72,606)	(87,481)
Net loss		$ (72,606)	$ (75,490)
Per share data:
Net loss per share attributable to Class A and Class B common stockholders - basic (in dollars per share)	[1]	$ (0.15)	$ (0.16)
Net loss per share attributable to Class A and Class B common stockholders - diluted (in dollars per share)	[1]	$ (0.15)	$ (0.16)
As computed excluding anticipated net investment income
Accounting Policies [Line Items]
Premium deficiency reserve benefit		$ (4,097)	$ (27,657)
Total operating expenses		598,094	961,679
Loss from operations		(70,319)	(87,300)
Net loss		$ (70,319)	$ (75,309)
Per share data:
Net loss per share attributable to Class A and Class B common stockholders - basic (in dollars per share)		$ (0.15)	$ (0.16)
Net loss per share attributable to Class A and Class B common stockholders - diluted (in dollars per share)		$ (0.15)	$ (0.16)
Effect of Change
Accounting Policies [Line Items]
Premium deficiency reserve benefit		$ 2,287	$ 181
Total operating expenses		2,287	181
Loss from operations		(2,287)	(181)
Net loss		$ (2,287)	$ (181)
Per share data:
Net loss per share attributable to Class A and Class B common stockholders - basic (in dollars per share)		$ 0	$ 0
Net loss per share attributable to Class A and Class B common stockholders - diluted (in dollars per share)		$ 0	$ 0

[1] (1) Because the Company had a net loss during the three months ended March 31, 2023 and 2022, the Company's potentially dilutive securities, which include stock options, restricted stock, preferred stock, and warrants to purchase shares of common stock and preferred stock, have been excluded from the computation of diluted net loss per share, as the effect would be anti-dilutive.