Acquisition Of JOTEC (Narrative) (Details) - USD ($) $ in Thousands			1 Months Ended	3 Months Ended	12 Months Ended
	Dec. 01, 2017	Oct. 10, 2017	Dec. 31, 2017	Mar. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Term loan balance			$ 228,969	$ 228,365	$ 228,969
Additional goodwill from JOTEC Acquisition				$ 1,359
JOTEC [Member]
Business Acquisition [Line Items]
Agreement date				Dec. 01, 2017
Acquisition price		$ 225,000
Cash consideration	$ 168,800
Common shares issued					2,682,754
Common stock value issued in business combination					$ 53,100
Escrow deposit, part of payments to acquire business	$ 22,500
Transaction and integration costs				$ 3,400
Revenues			4,100
Net loss			(1,500)		$ (736)	$ (1,966)
Pro forma tax rate				38.00%	38.00%
JOTEC [Member] | Common Stock [Member]
Business Acquisition [Line Items]
Common shares issued	2,682,754
Common stock value issued in business combination	$ 53,100
Term Loan [Member]
Business Acquisition [Line Items]
Term loan balance			$ 225,000	$ 224,438	$ 225,000
Term Loan [Member] | JOTEC [Member]
Business Acquisition [Line Items]
Term loan balance	225,000
Senior Secured Credit Facility [Member] | JOTEC [Member]
Business Acquisition [Line Items]
Credit facility aggregate commitments	255,000
Revolving Credit Facility [Member] | JOTEC [Member]
Business Acquisition [Line Items]
Credit facility aggregate commitments	$ 30,000