Variable Interest Entities (VIEs) (Details) - USD ($)	Sep. 30, 2019	Jan. 01, 2019	Dec. 31, 2018	Sep. 30, 2018	Dec. 31, 2017
Current assets
Cash and cash equivalents	$ 230,298,252		$ 106,891,503	$ 119,779,499
Restricted cash	20,150		0
Investment in marketable securities	1,154,480		1,127,102
Receivables, net	19,731,189		7,127,217
Receivables, net – related party	37,708,178		49,328,739
Prepaid expenses and other current assets	10,495,938		7,385,098
Loans receivable - related parties	6,425,000		0
Total current assets	321,360,707		172,862,792
Noncurrent assets
Land, property and equipment, net	12,427,107		12,721,082
Intangible assets, net	114,166,305		86,875,883
Goodwill	237,134,772		185,805,880
Loans receivable – related parties	12,500,000		17,500,000
Investments in other entities – equity method	35,840,105		34,876,980
Restricted cash	746,104		745,470
Right-of-use assets	13,540,129	$ 9,000,000
Other assets	1,633,153		1,205,962
Total noncurrent assets	428,883,675		340,136,257
Total assets	750,244,382		512,999,049
Current liabilities
Accounts payable and accrued expenses	35,539,917		25,075,489
Fiduciary accounts payable	1,734,142		1,538,598
Medical liabilities	53,819,647		33,641,701		$ 63,972,318
Bank loan	0		40,257
Dividends payable	271,279			$ 0
Operating lease liabilities	2,836,010
Capital lease obligations	101,741		101,741
Total current liabilities	105,195,228		72,019,647
Noncurrent liabilities
Lines of credit	250,000,000
Deferred tax liability	30,199,423		19,615,935
Fiduciary accounts payable	1,185,025		1,185,025
Operating lease liabilities	10,670,364		0
Capital lease obligations	441,241		517,261
Total noncurrent liabilities	276,645,116		34,318,221
Total liabilities	381,840,344		106,337,868
Variable Interest Entity, Primary Beneficiary
Current assets
Cash and cash equivalents	201,806,867		71,726,342
Restricted cash	20,150		0
Investment in marketable securities	1,087,197		1,066,103
Receivables, net	17,992,524		3,904,586
Receivables, net – related party	36,046,032		45,258,916
Prepaid expenses and other current assets	5,557,928		3,647,654
Loans receivable - related parties	6,425,000		0
Total current assets	268,935,698		125,603,601
Noncurrent assets
Land, property and equipment, net	9,698,849		9,602,228
Intangible assets, net	91,539,651		58,984,420
Goodwill	107,551,295		56,213,450
Loans receivable – related parties	12,500,000		12,500,000
Investment in a privately held entity that does not report net asset value per share	4,725,000		4,725,000
Investments in other entities – equity method	35,840,977		26,707,404
Restricted cash	746,104		745,470
Right-of-use assets	3,758,391		0
Other assets	1,058,601		839,085
Total noncurrent assets	267,418,868		170,317,057
Total assets	536,354,566		295,920,658
Current liabilities
Accounts payable and accrued expenses	8,811,988		6,378,751
Fiduciary accounts payable	1,734,142		1,538,598
Medical liabilities	48,759,183		24,983,110
Income taxes payable	1,393,492		11,621,861
Amount due to affiliate	26,859,007		11,505,680
Bank loan	0		40,257
Dividends payable	271,279		0
Operating lease liabilities	837,984		0
Capital lease obligations	101,741		101,741
Total current liabilities	88,768,816		56,169,998
Noncurrent liabilities
Lines of credit	0		0
Deferred tax liability	23,765,062		15,693,159
Fiduciary accounts payable	1,185,025		1,185,025
Operating lease liabilities	2,861,560
Capital lease obligations	441,241		517,261
Total noncurrent liabilities	28,252,888		17,395,445
Total liabilities	$ 117,021,704		$ 73,565,443