Segment Results Narrative (Details)	3 Months Ended
Mar. 31, 2018 $ / shares	Mar. 31, 2017 $ / shares
Segment Reporting [Abstract]
Number of Reportable Segments	4	3
Segment Reporting Information [Line Items]
Concentration Risk, Supplier	We currently buy a majority of our integrated circuit boards, an important component in our products, from two suppliers. Management believes that other suppliers could provide similar circuit boards, but a change in suppliers, disputes with our suppliers, or unexpected constraints on the suppliers' production capacity could adversely affect operating results.
Earnings (loss) per common share - Basic	$ (3.74)	$ 0.41
Earnings (loss) per common share - Diluted	$ (3.74)	$ 0.40

Description of risks that arise due to the volume of business transacted with a particular supplier or reliance placed on that supplier. At a minimum, the description informs financial statement users of the general nature of the risk.

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