Segment Reporting and Foreign Operations - Assets, Depreciation, Amortization and Capital Expenditures (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	$ 1,620,012	$ 1,111,811	$ 942,803
Depreciation and amortization	69,546	53,582	43,755
Capital expenditures	63,324	38,623	32,837
Cardiovascular
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	1,588,970	1,103,806	932,927
Depreciation and amortization	68,722	52,700	42,806
Capital expenditures	63,032	38,437	32,613
Endoscopy
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	31,042	8,005	9,876
Depreciation and amortization	824	882	949
Capital expenditures	$ 292	$ 186	$ 224