Segment and Related Information - Financial Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
SEGMENT AND RELATED INFORMATION
Net revenues	$ 281,098	$ 266,966	$ 517,517	$ 500,961
Material costs	91,399	86,516	169,776	162,872
Personnel expenses	91,490	89,554	178,201	175,662
Depreciation & amortization	8,760	9,272	17,533	18,602
Segment income from operations	23,103	20,329	21,124	20,952
Purchase of property, plant and equipment			14,806	11,322
Patient Care
SEGMENT AND RELATED INFORMATION
Net revenues	231,168	218,158	421,769	406,665
Material costs	69,137	65,909	128,287	123,808
Personnel expenses	78,419	76,792	152,128	150,405
Other expenses	37,336	35,439	74,769	70,443
Depreciation & amortization	4,502	4,998	9,054	9,896
Segment income from operations	41,774	35,020	57,531	52,113
Patient Care | Operating segments
SEGMENT AND RELATED INFORMATION
Net revenues	231,168	218,158	421,769	406,665
Material costs	62,948	59,989	116,303	112,164
Patient Care | Intersegments
SEGMENT AND RELATED INFORMATION
Material costs	6,189	5,920	11,984	11,644
Products & Services
SEGMENT AND RELATED INFORMATION
Net revenues	101,626	98,643	192,323	186,653
Material costs	73,958	70,442	138,064	131,421
Personnel expenses	13,071	12,762	26,073	25,257
Other expenses	7,077	5,483	14,025	11,638
Depreciation & amortization	2,596	2,503	5,139	5,005
Segment income from operations	4,924	7,453	9,022	13,332
Products & Services | Operating segments
SEGMENT AND RELATED INFORMATION
Net revenues	49,930	48,808	95,748	94,296
Material costs	28,451	26,527	53,473	50,708
Products & Services | Intersegments
SEGMENT AND RELATED INFORMATION
Net revenues	51,696	49,835	96,575	92,357
Material costs	$ 45,507	$ 43,915	$ 84,591	$ 80,713