Accounts Receivable - Segment (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Accounts Receivable
Trade accounts receivable - net	$ 55,911	$ 58,212
Rail, Technologies, and Services
Accounts Receivable
Trade accounts receivable - net	34,827	33,960
Precast Concrete Products
Accounts Receivable
Trade accounts receivable - net	10,809	11,119
Steel Products and Measurement
Accounts Receivable
Trade accounts receivable - net	$ 10,275	$ 13,133