Variable Interest Entities (VIEs) (Details) - USD ($) $ in Thousands		Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020	Dec. 31, 2019
Current assets
Cash and cash equivalents		$ 205,876	$ 193,470	$ 80,892	$ 103,189
Investment in marketable securities		66,931	67,695
Receivables, net		16,448	7,058
Receivables, net – related party		66,872	49,260
Other receivables		4,518	4,297
Prepaid expenses and other current assets		9,630	16,797
Total current assets		370,275	338,577
Noncurrent assets
Intangible assets, net		83,199	86,985
Goodwill		239,053	239,053
Loans receivable – related parties		4,129	4,145
Investments in other entities – equity method		42,615	43,292
Restricted cash – long term		0	500
Operating lease right-of-use assets		17,738	18,574
Other assets		19,107	18,915
Total noncurrent assets		473,005	478,909
Total assets	[1]	843,280	817,486
Current liabilities
Accounts payable and accrued expenses		40,234	36,143
Fiduciary accounts payable		6,871	9,642
Medical liabilities		51,479	50,330	$ 63,698	$ 58,725
Dividends payable		481	485
Current portion of long-term debt		12,078	10,889
Finance lease liabilities		109	102
Operating lease liabilities		3,036	3,177
Total current liabilities		126,347	114,992
Noncurrent liabilities
Long-term debt		226,937	230,211
Deferred tax liability		10,038	10,959
Finance lease liabilities, net of current portion		277	311
Operating lease liabilities, net of current portion		15,147	15,865
Total noncurrent liabilities		252,399	257,346
Total liabilities	[1]	378,746	372,338
Variable Interest Entity, Primary Beneficiary
Current assets
Cash and cash equivalents		128,341	126,158
Investment in marketable securities		66,862	67,637
Receivables, net		14,911	5,155
Receivables, net – related party		64,699	46,718
Other receivables		734	1,084
Prepaid expenses and other current assets		7,711	14,863
Total current assets		283,258	261,615
Noncurrent assets
Land, property and equipment, net		27,439	27,599
Intangible assets, net		66,342	69,250
Goodwill		109,460	109,460
Loans receivable – related parties		4,129	4,145
Investment in affiliates		336,611	225,144
Investments in other entities – equity method		42,838	43,516
Investment in privately held entities		36,584	36,584
Restricted cash – long term		0	500
Operating lease right-of-use assets		5,950	6,298
Other assets		17,335	17,177
Total noncurrent assets		646,688	539,673
Total assets		929,946	801,288
Current liabilities
Accounts payable and accrued expenses		11,260	12,963
Fiduciary accounts payable		6,871	9,642
Medical liabilities		38,134	37,684
Income taxes payable		7,581	4,225
Dividends payable		481	485
Amount due to affiliate		27,742	22,698
Current portion of long-term debt		203	201
Finance lease liabilities		109	102
Operating lease liabilities		1,287	1,242
Total current liabilities		93,668	89,242
Noncurrent liabilities
Long-term debt		7,328	7,379
Deferred tax liability		9,128	9,144
Finance lease liabilities, net of current portion		277	311
Operating lease liabilities, net of current portion		4,870	5,242
Total noncurrent liabilities		21,603	22,076
Total liabilities		$ 115,271	$ 111,318

[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 $929.9 million and $801.3 million as of March 31, 2021 and December 31, 2020, 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 $115.3 million and $111.3 million as of March 31, 2021 and December 31, 2020, respectively. See Note 14 – Variable Interest Entities (VIEs) for further detail.