Segment Reporting and Foreign Operations - Operating Income (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Net Sales	$ 190,897	$ 179,337	$ 186,549	$ 171,069	$ 157,715	$ 156,975	$ 151,071	$ 138,077	$ 727,852	$ 603,838	$ 542,149
Operating expenses									293,184	230,149	198,238
Operating income (loss)	13,219	879	13,362	5,609	12,602	2,987	11,581	7,706	33,069	34,876	37,543
Total other expense - net									2,812	(9,490)	(6,343)
Income tax expense	4,474	1,364	1,830	690	2,116	(978)	2,572	1,555	8,358	5,265	7,398
NET INCOME	$ 6,806	$ (3,569)	$ 9,483	$ 14,803	$ 7,507	$ 973	$ 7,290	$ 4,351	27,523	20,121	23,802
Cardiovascular
Segment Reporting Information [Line Items]
Net Sales									700,613	580,151	520,915
Operating expenses									281,095	218,659	187,492
Operating income (loss)									24,819	30,053	34,052
Endoscopy
Segment Reporting Information [Line Items]
Net Sales									27,239	23,687	21,234
Operating expenses									12,089	11,490	10,746
Operating income (loss)									$ 8,250	$ 4,823	$ 3,491