Business Combinations and Goodwill - Identifiable Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands			9 Months Ended
	Aug. 30, 2019	May 31, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Assets acquired
Goodwill			$ 239,053		$ 238,505
Cash paid			$ 0	$ 49,403
Accountable Health Care, IPA | Dr. Jay
Assets acquired
Cash and cash equivalents	$ 582
Accounts receivable, net	5,150
Other current assets	198
Network relationship intangible assets	11,411
Goodwill	23,566
Accounts payable	(3,759)
Medical liabilities	(12,154)
Subordinated loan	(15,327)
Net assets acquired	9,667
Equity investment contributed	2,417
Cash paid	$ 7,250
APC and APC-LSMA | Alpha Care Medical Group, Inc.
Assets acquired
Cash and cash equivalents		$ 3,569
Accounts receivable, net		10,336
Other current assets		4,675
Network relationship intangible assets		22,636
Goodwill		28,585
Accounts payable		(2,795)
Deferred tax liabilities		(6,334)
Medical liabilities		(15,616)
Net assets acquired		45,056
Cash paid		$ 45,056