CARES Act (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		18 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Dec. 31, 2020	Apr. 30, 2020
Unusual or Infrequent Items, or Both [Abstract]
Government assistance, provider relief payments received, CARES Act					$ 208,400
Government assistance recognized in earnings, CARES Act	$ 1,700	$ (1,200)	$ 115,800	$ 53,800
Unearned government assistance, CARES Act	2,414		2,414		2,414	$ 82,607
Unearned government assistance, amount expected to be repaid, CARES Act	1,600		1,600		1,600
Government advances, CARES Act	159,505		159,505		$ 159,505	$ 321,807	$ 325,000
Government advances recouped, CARES Act	$ 91,800		$ 165,500