BASIS OF PRESENTATION - Accounts Receivable Aging (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross accounts receivable	$ 154,760	$ 157,042
Allowance for doubtful accounts	(51,072)	(59,689)
Net accounts receivable	103,688	97,353
Government
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross accounts receivable	26,766	31,313
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross accounts receivable	113,015	114,690
Patient
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross accounts receivable	14,979	11,039
Receivables 0 to 180 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross accounts receivable	117,456	119,435
Receivables 0 to 180 Days Past Due | Government
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross accounts receivable	17,977	19,944
Receivables 0 to 180 Days Past Due | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross accounts receivable	93,247	94,477
Receivables 0 to 180 Days Past Due | Patient
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross accounts receivable	6,232	5,014
Receivables Over 180 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross accounts receivable	37,304	37,607
Receivables Over 180 Days Past Due | Government
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross accounts receivable	8,789	11,369
Receivables Over 180 Days Past Due | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross accounts receivable	19,768	20,213
Receivables Over 180 Days Past Due | Patient
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross accounts receivable	$ 8,747	$ 6,025