Revenue (Tables)

12 Months Ended

Dec. 31, 2020

Revenue from Contract with Customer [Abstract]

Disaggregation of Revenue

For the years ended December 31, 2020, 2019, and 2018, net sales by the timing of the transfer of goods and services were as follows:

Year Ended December 31, 2020	Rail Technologies and Services		Infrastructure Solutions		Total
Point in time	$	212,212	$	139,179	$	351,391
Over time	64,235		81,785		146,020
Total net sales	$	276,447	$	220,964	$	497,411
Year Ended December 31, 2019	Rail Technologies and Services		Infrastructure Solutions		Total
Point in time	$	240,047	$	189,606	$	429,653
Over time	81,761		105,014		186,775
Total net sales	$	321,808	$	294,620	$	616,428
Year Ended December 31, 2018	Rail Technologies and Services		Infrastructure Solutions		Total
Point in time	$	232,814	$	184,997	$	417,811
Over time	86,710		76,543		163,253
Total net sales	$	319,524	$	261,540	$	581,064