Definite-lived Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Intangible assets by major classification
Intangible amortization expense	$ 191	$ 194	$ 389	$ 389
Gross	5,388		5,388		$ 5,388
Accumulated Amortization	(2,016)		(2,016)		(1,627)
Net Book Value	3,372		$ 3,372		3,761
Minimum
Intangible assets by major classification
Definite-lived intangible assets useful life			5 years
Maximum
Intangible assets by major classification
Definite-lived intangible assets useful life			15 years
Customer relationships
Intangible assets by major classification
Gross	4,703		$ 4,703		4,703
Accumulated Amortization	(1,735)		(1,735)		(1,400)
Net Book Value	2,968		2,968		3,303
Software acquired in the acquisition of Railtronix
Intangible assets by major classification
Gross	346		346		346
Accumulated Amortization	(128)		(128)		(103)
Net Book Value	218		218		243
Non-competition agreement
Intangible assets by major classification
Gross	225		225		225
Accumulated Amortization	(116)		(116)		(94)
Net Book Value	109		109		131
Patents and other
Intangible assets by major classification
Gross	114		114		114
Accumulated Amortization	(37)		(37)		(30)
Net Book Value	$ 77		$ 77		$ 84