Variable Interest Entities (VIEs) - Eliminated Upon Consolidation Included In Accompanying Consolidated Balance Sheets (Details) - USD ($) $ in Thousands		Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022	Dec. 31, 2021
Current assets
Cash and cash equivalents		$ 274,613	$ 288,027
Investments in marketable securities		4,114	5,567
Receivables, net		79,003	52,629
Receivables, net – related party		74,877	65,147
Other receivables		1,929	1,834
Prepaid expenses and other current assets		22,170	14,798
Loans receivable		973	996
Loan receivable – related party		0	2,125
Total current assets		457,688	435,138
Non-current assets
Intangible assets, net		77,675	76,861
Goodwill		276,028	275,675
Investments in other entities – equity method		43,108	40,299
Operating lease right-of-use assets		18,431	20,444
Other assets		5,441	6,056
Total non-current assets		534,940	528,767
Total assets	[1]	992,628	963,905
Current liabilities
Accounts payable and accrued expenses		49,486	49,562
Fiduciary accounts payable		8,976	8,065
Medical liabilities		101,394	84,253	$ 95,758	$ 55,783
Dividends payable		664	664
Current portion of long-term debt		621	619
Finance lease liabilities		579	594
Operating lease liabilities		3,234	3,572
Total current liabilities		164,954	147,329
Non-current liabilities
Long-term debt, net of current portion and deferred financing costs		204,944	203,389
Deferred tax liability		3,695	3,042
Finance lease liabilities, net of current portion		1,136	1,275
Operating lease liabilities, net of current portion		18,164	19,915
Other long-term liabilities		21,806	20,260
Total non-current liabilities		249,745	247,881
Total liabilities	[1]	414,699	395,210
Variable Interest Entity, Primary Beneficiary
Current assets
Cash and cash equivalents		96,018	97,669
Investments in marketable securities		1,538	4,543
Receivables, net		14,369	11,503
Receivables, net – related party		70,565	62,190
Other receivables		1,268	1,236
Prepaid expenses and other current assets		18,241	9,289
Loans receivable		0	22
Loan receivable – related party		0	2,125
Amount due from affiliates		33,979	30,340
Total current assets		235,978	218,917
Non-current assets
Land, property, and equipment, net		110,829	106,486
Intangible assets, net		51,667	53,964
Goodwill		116,804	118,161
Investment in affiliates		375,614	304,755
Investments in other entities – equity method		29,758	27,561
Investment in privately held entities		405	405
Operating lease right-of-use assets		4,961	6,503
Other assets		3,513	4,169
Total non-current assets		693,551	622,004
Total assets		929,529	840,921
Current liabilities
Accounts payable and accrued expenses		22,823	23,632
Fiduciary accounts payable		8,923	7,853
Medical liabilities		43,948	48,100
Income taxes payable		8,065	1,083
Dividends payable		638	638
Current portion of long-term debt		621	619
Finance lease liabilities		579	594
Operating lease liabilities		1,489	1,800
Total current liabilities		87,086	84,319
Non-current liabilities
Long-term debt, net of current portion and deferred financing costs		27,965	26,645
Deferred tax liability		813	1,465
Finance lease liabilities, net of current portion		1,136	1,275
Operating lease liabilities, net of current portion		6,136	7,484
Other long-term liabilities		8,686	8,542
Total non-current liabilities		44,736	45,411
Total liabilities		$ 131,822	$ 129,730

[1] The Company’s consolidated balance sheets include the assets and liabilities of its consolidated VIEs. The consolidated balance sheets include total assets that can be used only to settle obligations of the Company’s consolidated VIEs totaling $519.9 million and $505.8 million as of March 31, 2023 and December 31, 2022, respectively, and total liabilities of the Company’s consolidated VIEs for which creditors do not have recourse to the general credit of the primary beneficiary of $131.8 million and $129.7 million as of March 31, 2023 and December 31, 2022, respectively. The VIE balances do not include $375.6 million of investment in affiliates and $34.0 million of amounts due from affiliates as of March 31, 2023 and $304.8 million of investment in affiliates and $30.3 million of amounts due from affiliates as of December 31, 2022 as these are eliminated upon consolidation and not presented within the consolidated balance sheets. See Note 16 — “Variable Interest Entities (VIEs)” for further detail.