Business Segments (Detail Textuals)	3 Months Ended	12 Months Ended
	Mar. 31, 2019 USD ($) Segment	Dec. 31, 2018 USD ($) Segment
Segment Reporting Information [Line Items]
Total identifiable assets	$ 42,651,000	$ 41,685,000
Number of operating segments | Segment	2	2
Operating Segments | ATG
Segment Reporting Information [Line Items]
Total identifiable assets	$ 32,580,000	$ 31,639,000
Operating Segments | CPG
Segment Reporting Information [Line Items]
Total identifiable assets	$ 10,071,000	$ 10,046,000