Business Segments (Assets by Segment) (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Assets	$ 611,574	$ 495,121
Less: LIFO reserve	(7,708)	(8,289)
Rail Products and Services [Member]
Segment Reporting Information [Line Items]
Assets	263,208	239,951
Construction Products [Member]
Segment Reporting Information [Line Items]
Assets	96,764	102,978
Tubular and Energy Services [Member]
Segment Reporting Information [Line Items]
Assets	226,692	130,289
Unallocated Corporate Assets [Member]
Segment Reporting Information [Line Items]
Assets	$ 32,618	$ 30,192