Supplemental Cash Flow Information - Summary of Cash, Cash Equivalents and Restricted Cash Equivalents from Continuing Operations (Details) - USD ($) $ in Thousands		Mar. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Supplemental Cash Flow Elements [Abstract]
Cash and cash equivalents		$ 1,021,754	$ 1,040,039
Restricted cash and equivalents	[1]	14,470	14,781
Cash, cash equivalents and restricted cash equivalents		$ 1,036,224	$ 1,054,820	$ 135,178

[1] Restricted cash and equivalents primarily consist of amounts used as collateral to secure letters of credit that the Company is required to maintain pursuant to contracts with payors.