Segment Reporting - Operating Income (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 Reporting Information [Line Items]
Net sales	$ 255,532		$ 224,810		$ 493,881	$ 427,844
Operating income	12,201		15,114		21,724	23,895
Total other expense - net	(3,202)		(3,549)		(5,879)	(5,970)
Income tax expense	2,140		624		2,791	1,715
Net income	6,859	$ 6,195	10,941	$ 5,269	13,054	16,210
Cardiovascular
Segment Reporting Information [Line Items]
Net sales	246,666		216,387		477,146	412,241
Operating income	9,855		12,663		17,474	19,060
Endoscopy
Segment Reporting Information [Line Items]
Net sales	8,866		8,423		16,735	15,603
Operating income	$ 2,346		$ 2,451		$ 4,250	$ 4,835