Intangible Assets (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	$ 111	$ 108	$ 221	$ 207
2018	442		442
2019	412		412
2020	406		406
2021	406		406
2022	$ 88		$ 88
Customer Lists [Member] | Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets amortization period			7 years
Customer Lists [Member] | Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets amortization period			10 years
Patents [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets amortization period			18 years
Software [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets amortization period			3 years
Other [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets amortization period			15 years
Non-compete Agreements [Member] | Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets amortization period			2 years
Non-compete Agreements [Member] | Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets amortization period			5 years