SEGMENT AND RELATED INFORMATION - SEGMENT INFORMATION (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018 USD ($) area	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($) segment area	Sep. 30, 2017 USD ($)
SEGMENT AND RELATED INFORMATION
Number of operating segments | segment			2
Net revenues	$ 262,946	$ 257,966	$ 763,907	$ 755,033
Material costs	84,805	82,345	247,677	240,407
Personnel expenses	90,853	90,065	266,515	265,851
Other expenses	62,414	66,384	185,287	202,718
Depreciation & amortization	8,950	9,632	27,552	29,594
Income (loss) from operations	15,924	9,540	36,876	16,463
Interest expense, net	8,939	15,097	28,519	43,197
Loss on extinguishment of debt			16,998
Non-service defined benefit plan expense	176	184	528	552
Income (loss) before income taxes	6,809	(5,741)	(9,169)	(27,286)
Provision (benefit) for income taxes	2,440	(1,580)	(3,848)	(7,028)
Net income (loss)	4,369	(4,161)	(5,321)	(20,258)
Corporate & Other
SEGMENT AND RELATED INFORMATION
Other expenses	21,682	24,272	62,474	76,389
Depreciation & amortization	1,735	1,879	5,436	5,780
Income (loss) from operations	(23,417)	(26,151)	(67,910)	(82,169)
Interest expense, net	(2,278)	3,699	(3,655)	8,879
Loss on extinguishment of debt			16,998
Non-service defined benefit plan expense	176	184	528	552
Income (loss) before income taxes	(21,315)	(30,034)	(81,781)	(91,600)
Provision (benefit) for income taxes	2,440	(1,580)	(3,848)	(7,028)
Net income (loss)	(23,755)	(28,454)	(77,933)	(84,572)
Intersegments
SEGMENT AND RELATED INFORMATION
Net revenues	(48,945)	(45,114)	(141,302)	(131,484)
Material costs	(48,945)	(45,114)	(141,302)	(131,484)
Consolidating Adjustments
SEGMENT AND RELATED INFORMATION
Net revenues	(48,945)	(45,114)	(141,302)	(131,484)
Material costs	$ (48,945)	(45,114)	$ (141,302)	(131,484)
Patient Care
SEGMENT AND RELATED INFORMATION
Medicare reimbursement for O&P products and services based on prices set forth in fee schedules, number of regional pricing areas | area	10		10
Net revenues	$ 214,080	210,637	$ 620,745	614,495
Material costs	58,395	56,748	170,559	165,680
Personnel expenses	77,806	78,161	228,211	229,582
Other expenses	34,426	35,861	104,869	107,124
Depreciation & amortization	4,651	5,324	14,547	16,123
Income (loss) from operations	32,502	28,546	84,615	78,243
Interest expense, net	7,984	8,123	22,429	24,409
Income (loss) before income taxes	24,518	20,423	62,186	53,834
Net income (loss)	24,518	20,423	62,186	53,834
Patient Care | Operating segments
SEGMENT AND RELATED INFORMATION
Net revenues	214,080	210,637	620,745	614,495
Material costs	64,695	62,745	188,503	183,423
Patient Care | Intersegments
SEGMENT AND RELATED INFORMATION
Material costs	6,300	5,997	17,944	17,743
Products & Services
SEGMENT AND RELATED INFORMATION
Net revenues	48,866	47,329	143,162	140,538
Material costs	26,410	25,597	77,118	74,727
Personnel expenses	13,047	11,904	38,304	36,269
Other expenses	6,306	6,251	17,944	19,205
Depreciation & amortization	2,564	2,429	7,569	7,691
Income (loss) from operations	6,839	7,145	20,171	20,389
Interest expense, net	3,233	3,275	9,745	9,909
Income (loss) before income taxes	3,606	3,870	10,426	10,480
Net income (loss)	3,606	3,870	10,426	10,480
Products & Services | Operating segments
SEGMENT AND RELATED INFORMATION
Net revenues	97,811	92,443	284,464	272,022
Material costs	69,055	64,714	200,476	188,468
Products & Services | Intersegments
SEGMENT AND RELATED INFORMATION
Net revenues	48,945	45,114	141,302	131,484
Material costs	$ 42,645	$ 39,117	$ 123,358	$ 113,741