Variable Interest Entities (VIEs) (Details) - USD ($) $ in Thousands		Sep. 30, 2023	Jun. 30, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Dec. 31, 2021
Current assets
Cash and cash equivalents		$ 273,941		$ 288,027	$ 184,016
Investment in marketable securities		3,021		5,567
Other receivables		1,501		1,834
Prepaid expenses and other current assets		13,953		14,798
Total current assets		476,229		428,125
Non-current assets
Intangible assets, net		74,209		76,861
Goodwill		275,528		269,053
Income taxes receivable		15,943		15,943
Investments in other entities – equity method		44,428	$ 45,832	40,299	38,954	$ 43,820	$ 41,715
Operating lease right-of-use assets		21,482		20,444
Other assets		8,586		6,056
Total non-current assets		597,032		538,088
Total assets	[1]	1,073,261		966,213
Current liabilities
Accounts payable and accrued expenses		53,136		49,562
Fiduciary accounts payable		6,257		8,065
Medical liabilities		97,519		81,255	$ 94,884		$ 55,783
Dividends payable		638		664
Amount due to affiliates		8,121		0
Current portion of long-term debt		2,991		619
Finance lease liabilities		655		594
Operating lease liabilities		3,528		3,572
Total current liabilities		202,957		148,610
Non-current liabilities
Long-term debt, net of current portion and deferred financing costs		206,213		203,389
Deferred tax liability		12,145		14,217
Finance lease liabilities, net of current portion		1,195		1,275
Operating lease liabilities, net of current portion		21,006		19,915
Other long-term liabilities		14,105		20,260
Total non-current liabilities		254,664		259,056
Total liabilities	[1]	457,621		407,666
Nonrelated Party
Current assets
Receivables, net		95,892		49,631
Loans receivable		973		996
Related Party
Current assets
Receivables, net		86,948		65,147
Loans receivable		0		2,125
Variable Interest Entity, Primary Beneficiary
Current assets
Cash and cash equivalents		103,227		97,669
Investment in marketable securities		522		4,543
Income taxes receivable		0		8,580
Other receivables		748		1,236
Prepaid expenses and other current assets		6,848		9,289
Amount due from affiliates		0		30,340
Total current assets		212,846		227,497
Non-current assets
Land, property, and equipment, net		125,308		106,486
Intangible assets, net		47,212		53,964
Goodwill		110,182		111,539
Income taxes receivable		15,943		15,943
Investment in affiliates		317,732		304,755
Investments in other entities – equity method		30,627		27,561
Investment in privately held entities		405		405
Operating lease right-of-use assets		6,336		6,503
Other assets		5,175		4,169
Total non-current assets		658,920		631,325
Total assets		871,766		858,822
Current liabilities
Accounts payable and accrued expenses		24,362		23,632
Fiduciary accounts payable		6,251		7,853
Medical liabilities		40,921		48,100
Income taxes payable		18,927		0
Dividends payable		638		638
Amount due to affiliates		16,261		0
Current portion of long-term debt		991		619
Finance lease liabilities		655		594
Operating lease liabilities		1,562		1,800
Total current liabilities		110,568		83,236
Non-current liabilities
Long-term debt, net of current portion and deferred financing costs		28,764		26,645
Deferred tax liability		1,948		4,591
Finance lease liabilities, net of current portion		1,194		1,275
Operating lease liabilities, net of current portion		7,397		7,484
Other long-term liabilities		8,745		8,542
Total non-current liabilities		48,048		48,537
Total liabilities		158,616		131,773
Variable Interest Entity, Primary Beneficiary | Nonrelated Party
Current assets
Receivables, net		18,895		11,503
Loans receivable		0		22
Variable Interest Entity, Primary Beneficiary | Related Party
Current assets
Receivables, net		82,606		62,190
Loans receivable		$ 0		$ 2,125

[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 $554.0 million and $523.7 million as of September 30, 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 $142.4 million and $131.8 million as of September 30, 2023 and December 31, 2022, respectively. The VIE balances do not include $317.7 million of investment in affiliates and $16.3 million of amounts due to affiliates as of September 30, 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.