Business Segments (Assets by Segment) (Detail) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Assets	$ 701,827	$ 495,121
Less: LIFO reserve	(7,889)	(8,289)
Rail Products and Services [Member]
Segment Reporting Information [Line Items]
Assets	257,856	239,951
Construction Products Segment [Member]
Segment Reporting Information [Line Items]
Assets	97,300	102,978
Tubular and Energy Services [Member]
Segment Reporting Information [Line Items]
Assets	318,521	130,289
Unallocated Corporate Assets [Member]
Segment Reporting Information [Line Items]
Assets	$ 36,039	$ 30,192