Revenue (Tables)

6 Months Ended

Jun. 30, 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 June 30,				Six Months Ended June 30,
	2019		2018		2019		2018
Rail Products	$	67,990	$	54,332	$	114,196	$	90,366
Rail Technologies	33,411		37,552		62,899		63,688
Rail Products and Services	101,401		91,884		177,095		154,054
Piling and Fabricated Bridge	37,588		25,846		61,320		44,707
Precast Concrete Products	17,818		16,361		31,431		26,400
Construction Products	55,406		42,207		92,751		71,107
Test, Inspection, and Threading Services	13,804		15,008		28,528		29,221
Protective Coatings and Measurement Systems	30,322		23,791		53,028		40,962
Tubular and Energy Services	44,126		38,799		81,556		70,183
Total net sales	$	200,933	$	172,890	$	351,402	$	295,344

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

	Three Months Ended June 30, 2019
	Rail Products and Services		Construction Products		Tubular and Energy Services		Total
Point in time	$	80,701	$	38,095	$	33,542	$	152,338
Over time	20,700		17,311		10,584		48,595
Total net sales	$	101,401	$	55,406	$	44,126	$	200,933
	Three Months Ended June 30, 2018
	Rail Products and Services		Construction Products		Tubular and Energy Services		Total
Point in time	$	69,295	$	28,196	$	34,923	$	132,414
Over time	22,589		14,011		3,876		40,476
Total net sales	$	91,884	$	42,207	$	38,799	$	172,890

	Six Months Ended June 30, 2019
	Rail Products and Services		Construction Products		Tubular and Energy Services		Total
Point in time	$	137,193	$	61,190	$	62,676	$	261,059
Over time	39,902		31,561		18,880		90,343
Total net sales	$	177,095	$	92,751	$	81,556	$	351,402
	Six Months Ended June 30, 2018
	Rail Products and Services		Construction Products		Tubular and Energy Services		Total
Point in time	$	115,166	$	47,122	$	61,358	$	223,646
Over time	38,888		23,985		8,825		71,698
Total net sales	$	154,054	$	71,107	$	70,183	$	295,344