SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details - Summary of net revenue) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenue from External Customer [Line Items]
Total net revenue	$ 257,211	$ 242,148	$ 244,395	$ 231,392	$ 235,552	$ 227,607	$ 230,014	$ 229,013	$ 975,146	$ 922,186	$ 884,535
Health Care, Patient Service
Revenue from External Customer [Line Items]
Service fee revenue, net of contractual allowances and discounts									868,741	857,178	821,587
Provision for bad debts										(46,555)	(45,387)
Commercial Insurance
Revenue from External Customer [Line Items]
Service fee revenue, net of contractual allowances and discounts									542,011	534,224	515,150
Medicare
Revenue from External Customer [Line Items]
Service fee revenue, net of contractual allowances and discounts									192,881	179,678	173,262
Medicaid
Revenue from External Customer [Line Items]
Service fee revenue, net of contractual allowances and discounts									25,615	24,133	23,272
Workers' compensation/personal injury
Revenue from External Customer [Line Items]
Service fee revenue, net of contractual allowances and discounts									34,193	32,969	31,791
Other patient revenue
Revenue from External Customer [Line Items]
Service fee revenue, net of contractual allowances and discounts									25,117	29,882	28,815
Management fee revenue
Revenue from External Customer [Line Items]
Service fee revenue, net of contractual allowances and discounts									13,882	13,127	11,868
Imaging on call and software
Revenue from External Customer [Line Items]
Service fee revenue, net of contractual allowances and discounts									16,261	18,116	19,462
Other
Revenue from External Customer [Line Items]
Service fee revenue, net of contractual allowances and discounts									18,781	25,049	17,967
Net service fee revenue
Revenue from External Customer [Line Items]
Service fee revenue, net of contractual allowances and discounts									868,741	810,623	776,200
Capitation Arrangements
Revenue from External Customer [Line Items]
Service fee revenue, net of contractual allowances and discounts									$ 106,405	$ 111,563	$ 108,335