Revenue

3 Months Ended

Mar. 31, 2020

Revenue from Contract with Customer [Abstract]

Revenue from products or services provided to customers over time accounted for 25.5% and 27.7% of revenue for the three months ended March 31, 2020 and 2019, respectively. Revenue under these long-term agreements is generally recognized over time either using an input measure based upon the proportion of actual costs incurred to estimated total project costs or an input measure based upon actual labor costs as a percentage of estimated total labor costs, depending upon which measure the Company believes best depicts the Company’s performance to date under the terms of the contract. Revenue recognized over time using an input measure was $24,432 and $31,837 for the three months ended March 31, 2020 and 2019, respectively. A certain portion of the Company’s revenue recognized over time under these long-term agreements is recognized using an output method, specifically units delivered, based upon certain customer acceptance and delivery requirements. Revenue recognized over time using an output measure was $8,345 and $9,911 for the three months ended March 31, 2020 and 2019, respectively. As of March 31, 2020 and December 31, 2019, the Company had contract assets of $32,438 and $37,032, respectively, that were recorded in “Inventories - net” within the Condensed Consolidated Balance Sheets. As of March 31, 2020 and December 31, 2019, the Company had contract liabilities of $5,840 and $4,472, respectively, that were recorded in “Deferred revenue” within the Condensed Consolidated Balance Sheets.

The majority of the Company’s revenue is from products transferred and services rendered to customers at a point in time. Point in time revenue accounted for 74.5% and 72.3% of revenue for the three months ended March 31, 2020 and 2019, respectively. The Company recognizes revenue at the point in time at which the customer obtains control of the product or service, which is generally when the product title passes to the customer upon shipment or the service has been rendered to the customer. In limited cases, title does not transfer and revenue is not recognized until the customer has received the products at a physical location.

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


	Three Months Ended March 31,
	2020		2019
Rail Products	$	43,562	$	46,206
Rail Technologies	26,642		29,488
Rail Products and Services	70,204		75,694
Piling and Fabricated Bridge	18,391		23,732
Precast Concrete Products	10,643		13,613
Construction Products	29,034		37,345
Test, Inspection, and Threading Services	9,704		14,724
Protective Coatings and Measurement Systems	19,833		22,706
Tubular and Energy Services	29,537		37,430
Total net sales	$	128,775	$	150,469

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


	Three Months Ended March 31, 2020
	Rail Products and Services		Construction Products		Tubular and Energy Services		Total
Point in time	$	54,888	$	16,883	$	24,227	$	95,998
Over time	15,316		12,151		5,310		32,777
Total net sales	$	70,204	$	29,034	$	29,537	$	128,775

	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

The timing of revenue recognition, billings, and cash collections results in billed receivables, costs in excess of billings (contract assets, included in “Inventories - net”), and billings in excess of costs (contract liabilities, included in “Deferred revenue”) on the Condensed Consolidated Balance Sheets.

Significant changes in contract assets during the three months ended March 31, 2020 resulted from transfers of $15,600 at the beginning of the period from contract assets to receivables. Significant changes in contract liabilities during the three months ended March 31, 2020 resulted from increases of $2,943 due to billings in excess of costs, excluding amounts recognized as revenue during the period. Contract liabilities were reduced due to revenue recognized during the three months ended March 31, 2020 and 2019 of $2,614 and $948, respectively, that were included in the contract liabilities at the beginning of each period.

As of March 31, 2020, the Company had approximately $237,691 of remaining performance obligations, which is also referred to as backlog. Approximately 7.9% of the March 31, 2020 backlog was related to projects that are anticipated to extend beyond March 31, 2021.