REVENUE RECOGNITION - Adjustments to Operating Results (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Patient Revenues, net	$ 141,431	$ 146,377	$ 423,798	$ 430,427
Operating Expenses	113,799	118,104	337,517	341,937
Total Expenses	147,397	$ 145,403	427,672	$ 424,437
Accounts Receivable	65,927		65,927		$ 64,929
Accumulated Deficit	(23,432)		(23,432)		$ (14,534)
Difference Between Revenue Guidance In Effect before And After Topic 606, Adjustment For Implicit Price Concession Of Bad Debt Expense | Accounting Standards Update 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Patient Revenues, net	3,903		11,155
Difference Between Revenue Guidance In Effect before And After Topic 606, Adjustment For Implementation | Accounting Standards Update 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Patient Revenues, net	(269)		(887)
Accounts Receivable	(887)		(887)
Accumulated Deficit	887		887
Difference Between Revenue Guidance In Effect before And After Topic 606, Allowance For Doubtful Accounts | Accounting Standards Update 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Accounts Receivable	16,235		16,235
Difference Between Revenue Guidance In Effect before And After Topic 606, Tax Adjustment | Accounting Standards Update 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Accumulated Deficit	(284)		(284)
Difference between Revenue Guidance in Effect before and after Topic 606 | Accounting Standards Update 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Patient Revenues, net	3,634		10,268
Operating Expenses	3,903		11,155
Total Expenses	3,903		11,155
Accounts Receivable	15,348		15,348
Accumulated Deficit	603		603
Calculated under Revenue Guidance in Effect before Topic 606
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Patient Revenues, net	145,065		434,066
Operating Expenses	117,702		348,672
Total Expenses	151,300		438,827
Accounts Receivable	81,275		81,275
Accumulated Deficit	$ (22,829)		$ (22,829)