Accounts Receivable - Segment (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Accounts Receivable
Trade, net	$ 58,212	$ 73,498
Rail Technologies and Services
Accounts Receivable
Trade, net	33,960	44,941
Infrastructure Solutions
Accounts Receivable
Trade, net	$ 24,252	$ 28,557

Amount, after allowance for credit loss, of right to consideration from customer for product sold and service rendered in normal course of business, classified as current.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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