Revenue (Tables)

6 Months Ended

Jun. 30, 2018

Revenue from Contract with Customer [Abstract]

Disaggregation of Revenue

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

	Three Months Ended June 30,				Six Months Ended June 30,
	2018		2017		2018		2017
Rail Products	$	54,332	$	44,399	$	90,366	$	78,764
Rail Technologies	37,552		24,948		63,688		47,063
Rail Products and Services	91,884		69,347		154,054		125,827
Piling and Fabricated Bridge	25,846		29,607		44,707		58,830
Precast Concrete Products	16,361		15,858		26,400		23,957
Construction Products	42,207		45,465		71,107		82,787
Test, Inspection, and Threading	15,008		13,050		29,221		23,932
Protective Coatings and Measurement Solutions	23,791		16,998		40,962		31,016
Tubular and Energy Services	38,799		30,048		70,183		54,948
Total net sales	$	172,890	$	144,860	$	295,344	$	263,562

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

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
Three Months Ended June 30, 2017	Rail Products and Services		Construction Products		Tubular and Energy Services		Total
Point in time	$	57,098	$	28,766	$	26,112	$	111,976
Over time	12,249		16,699		3,936		32,884
Total net sales	$	69,347	$	45,465	$	30,048	$	144,860
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
Six Months Ended June 30, 2017	Rail Products and Services		Construction Products		Tubular and Energy Services		Total
Point in time	$	102,664	$	53,390	$	47,051	$	203,105
Over time	23,163		29,397		7,897		60,457
Total net sales	$	125,827	$	82,787	$	54,948	$	263,562