Segment and Related Information - Reconciliation of the Reportable Segments (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
SEGMENT AND RELATED INFORMATION
(Loss) income from operations	$ 23,103		$ 20,329		$ 21,124	$ 20,952
Interest expense, net	8,481		7,317		17,019	19,580
Loss on extinguishment of debt						16,998
Non-service defined benefit plan expense	173		176		346	352
Income (loss) before income taxes	14,449		12,836		3,759	(15,978)
Provision (benefit) for income taxes	4,414		(92)		675	(6,288)
Net income (loss)	10,035	$ (6,951)	12,928	$ (22,618)	3,084	(9,690)
Consolidated net revenues	281,098		266,966		517,517	500,961
Consolidated material costs	91,399		86,516		169,776	162,872
Corporate & other
SEGMENT AND RELATED INFORMATION
(Loss) income from operations	(23,595)		(22,144)		(45,429)	(44,493)
Consolidating adjustments
SEGMENT AND RELATED INFORMATION
Consolidated net revenues	(51,696)		(49,835)		(96,575)	(92,357)
Consolidated material costs	(51,696)		(49,835)		(96,575)	(92,357)
Patient Care
SEGMENT AND RELATED INFORMATION
(Loss) income from operations	41,774		35,020		57,531	52,113
Consolidated net revenues	231,168		218,158		421,769	406,665
Consolidated material costs	69,137		65,909		128,287	123,808
Patient Care | Operating segments
SEGMENT AND RELATED INFORMATION
Consolidated net revenues	231,168		218,158		421,769	406,665
Consolidated material costs	62,948		59,989		116,303	112,164
Products & Services
SEGMENT AND RELATED INFORMATION
(Loss) income from operations	4,924		7,453		9,022	13,332
Consolidated net revenues	101,626		98,643		192,323	186,653
Consolidated material costs	73,958		70,442		138,064	131,421
Products & Services | Operating segments
SEGMENT AND RELATED INFORMATION
Consolidated net revenues	49,930		48,808		95,748	94,296
Consolidated material costs	$ 28,451		$ 26,527		$ 53,473	$ 50,708