Business Segments - Additional Information (Details)	9 Months Ended
	Sep. 30, 2020 USD ($) segment	Dec. 31, 2019 USD ($)
Segment Reporting Information [Line Items]
Number of operating segments | segment	2
Total identifiable assets	$ 53,632,000	$ 49,470,000
Operating Segments
Segment Reporting Information [Line Items]
Total identifiable assets	53,632,000	49,470,000
Operating Segments | ATG
Segment Reporting Information [Line Items]
Total identifiable assets	43,531,000	39,980,000
Operating Segments | CPG
Segment Reporting Information [Line Items]
Total identifiable assets	$ 10,101,000	$ 9,490,000