Revenues (Disaggregation of Revenue by Geographic Region) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Disaggregation of Revenue [Line Items]
Revenues	$ 52,850	$ 70,686
Product sales [Member]
Disaggregation of Revenue [Line Items]
Revenues	37,232	50,108
Services [Member]
Disaggregation of Revenue [Line Items]
Revenues	15,618	20,578
United States [Member]
Disaggregation of Revenue [Line Items]
Revenues	25,345	22,000
United States [Member] | Product sales [Member]
Disaggregation of Revenue [Line Items]
Revenues	19,564	13,577
United States [Member] | Services [Member]
Disaggregation of Revenue [Line Items]
Revenues	5,781	8,423
Canada [Member]
Disaggregation of Revenue [Line Items]
Revenues	24,996	47,175
Canada [Member] | Product sales [Member]
Disaggregation of Revenue [Line Items]
Revenues	16,621	35,698
Canada [Member] | Services [Member]
Disaggregation of Revenue [Line Items]
Revenues	8,375	11,477
Other Countries [Member]
Disaggregation of Revenue [Line Items]
Revenues	2,509	1,511
Other Countries [Member] | Product sales [Member]
Disaggregation of Revenue [Line Items]
Revenues	1,047	833
Other Countries [Member] | Services [Member]
Disaggregation of Revenue [Line Items]
Revenues	$ 1,462	$ 678