Revenue (Tables)

3 Months Ended

Mar. 31, 2019

Revenue from Contract with Customer [Abstract]

Disaggregation of Revenue

The following table summarizes the Company's net sales by major product and service category:

	Three Months Ended March 31,
	2019		2018
Rail Products	$	46,206	$	36,034
Rail Technologies	29,488		26,136
Rail Products and Services	75,694		62,170
Piling and Fabricated Bridge	23,732		18,861
Precast Concrete Products	13,613		10,039
Construction Products	37,345		28,900
Test, Inspection, and Threading Services	14,724		14,213
Protective Coatings and Measurement Systems	22,706		17,171
Tubular and Energy Services	37,430		31,384
Total net sales	$	150,469	$	122,454

Net sales by the timing of the transfer of goods and services is as follows:

	Three Months Ended March 31, 2019
	Rail Products and Services		Construction Products		Tubular and Energy Services		Total
Point in time	$	56,492	$	23,095	$	29,134	$	108,721
Over time	19,202		14,250		8,296		41,748
Total net sales	$	75,694	$	37,345	$	37,430	$	150,469
	Three Months Ended March 31, 2018
	Rail Products and Services		Construction Products		Tubular and Energy Services		Total
Point in time	$	45,871	$	18,926	$	26,435	$	91,232
Over time	16,299		9,974		4,949		31,222
Total net sales	$	62,170	$	28,900	$	31,384	$	122,454