ACCOUNTS RECEIVABLE, NET - Aging Categories (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accounts Receivable, net
0-60 Days	$ 118,066				$ 116,146
61-120 Days	27,650				28,156
121-180 Days	13,682				15,082
Over 180 Days	57,246				61,836
Accounts receivable, before allowances	216,644				221,220
Allowance for disallowed revenue	(56,233)				(61,137)				$ (81,306)	$ (87,192)
Allowance for doubtful accounts	(14,065)	$ (13,472)	$ (13,109)	$ (13,611)	(15,521)	$ (14,418)	$ (15,241)	$ (16,296)	$ (15,027)	$ (9,944)
Accounts receivable, net	146,346	$ 134,424	$ 133,646	$ 125,776	144,562	$ 139,203	$ 145,605	$ 149,816
Patient Care
Accounts Receivable, net
Accounts receivable, before allowances	193,150				193,835
Allowance for disallowed revenue	(56,233)				(61,137)
Allowance for doubtful accounts	(9,894)				(10,575)
Accounts receivable, net	127,023				122,123
Patient Care | Non-Medicare
Accounts Receivable, net
0-60 Days	69,553				67,040
61-120 Days	16,850				16,653
121-180 Days	9,067				8,996
Over 180 Days	22,968				24,623
Accounts receivable, before allowances	118,438				117,312
Patient Care | Commercial insurance (excluding Medicare and Medicaid Managed Care)
Accounts Receivable, net
0-60 Days	50,310				48,568
61-120 Days	11,649				11,677
121-180 Days	6,302				6,050
Over 180 Days	15,279				17,453
Accounts receivable, before allowances	83,540				83,748
Patient Care | Private pay
Accounts Receivable, net
0-60 Days	880				897
61-120 Days	447				547
121-180 Days	381				441
Over 180 Days	1,311				1,034
Accounts receivable, before allowances	3,019				2,919
Patient Care | Medicaid
Accounts Receivable, net
0-60 Days	13,785				13,937
61-120 Days	3,561				3,554
121-180 Days	1,832				2,110
Over 180 Days	5,684				5,415
Accounts receivable, before allowances	24,862				25,016
Patient Care | VA
Accounts Receivable, net
0-60 Days	4,578				3,638
61-120 Days	1,193				875
121-180 Days	552				395
Over 180 Days	694				721
Accounts receivable, before allowances	7,017				5,629
Patient Care | Medicare
Accounts Receivable, net
0-60 Days	34,197				32,980
61-120 Days	5,725				4,813
121-180 Days	3,396				3,055
Over 180 Days	31,394				35,675
Accounts receivable, before allowances	74,712				76,523
Products & Services
Accounts Receivable, net
Accounts receivable, before allowances	23,494				27,385
Allowance for doubtful accounts	(4,171)				(4,946)
Accounts receivable, net	19,323				22,439
Products & Services | Trade accounts receivable
Accounts Receivable, net
0-60 Days	14,316				16,126
61-120 Days	5,075				6,690
121-180 Days	1,219				3,031
Over 180 Days	2,884				1,538
Accounts receivable, before allowances	$ 23,494				$ 27,385