Segment and Related Information - Financial Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
SEGMENT AND RELATED INFORMATION
Net revenues	$ 279,638	$ 262,946	$ 797,155	$ 763,907
Material costs	92,034	84,805	261,810	247,677
Personnel expenses	94,594	90,853	272,795	266,515
Depreciation & amortization	9,373	8,950	26,906	27,552
Segment income from operations	17,403	15,924	38,527	36,876
Patient Care
SEGMENT AND RELATED INFORMATION
Net revenues	230,931	214,080	652,700	620,745
Material costs	71,339	64,695	199,626	188,503
Personnel expenses	81,274	77,806	233,402	228,211
Other expenses	37,245	34,426	112,014	104,869
Depreciation & amortization	4,943	4,651	13,997	14,547
Segment income from operations	36,130	32,502	93,661	84,615
Patient Care | Operating segments
SEGMENT AND RELATED INFORMATION
Net revenues	230,931	214,080	652,700	620,745
Material costs	65,055	58,395	181,358	170,559
Patient Care | Intersegments
SEGMENT AND RELATED INFORMATION
Material costs	6,284	6,300	18,268	17,944
Products & Services
SEGMENT AND RELATED INFORMATION
Net revenues	102,377	97,811	294,700	284,464
Material costs	74,365	69,055	212,429	200,476
Personnel expenses	13,320	13,047	39,393	38,304
Other expenses	6,858	6,306	20,883	17,944
Depreciation & amortization	2,723	2,564	7,862	7,569
Segment income from operations	5,111	6,839	14,133	20,171
Products & Services | Operating segments
SEGMENT AND RELATED INFORMATION
Net revenues	48,707	48,866	144,455	143,162
Material costs	26,979	26,410	80,452	77,118
Products & Services | Intersegments
SEGMENT AND RELATED INFORMATION
Net revenues	53,670	48,945	150,245	141,302
Material costs	$ 47,386	$ 42,645	$ 131,977	$ 123,358