Leases (Narrative) (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018	Jan. 01, 2019
Lessee, Lease, Description [Line Items]
Finance lease obligation	$ 4,523	$ 5,049
Finance lease right-of-use assets	6,186	6,750
Operating lease right-of-use assets	5,461	0
Operating lease, liability	5,480	0
Germany
Lessee, Lease, Description [Line Items]
Finance lease obligation	4,500	5,000
Finance lease right-of-use assets	6,200	6,700
Finance lease, right-of-use asset, amortization	3,600	$ 3,500
Accounting Standards Update 2016-02
Lessee, Lease, Description [Line Items]
Operating lease right-of-use assets			$ 6,200
Operating lease, liability			$ 6,200
Additional operating lease asset recognized	800
Additional operating lease liability recognized	800
Scenario, Adjustment
Lessee, Lease, Description [Line Items]
Operating lease right-of-use assets	7,000
Operating lease, liability	$ 7,000