Business Segments (Schedule Of Reporting Sement Data To Consolidated Totals From Continuing Ops) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended										12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012		Jun. 30, 2012		Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Segment Reporting Information [Line Items]
Net Sales	$ 140,724	$ 170,346	[1]	$ 163,180	[2]	$ 114,291	$ 133,735	$ 158,323	$ 169,591	$ 113,688	$ 588,541	$ 575,337	$ 467,058
Income from continuing operations, before income taxes											23,830	32,652	31,964
Assets	406,122						379,894				406,122	379,894	378,402
Depreciation and amortization											12,973	12,007	9,219
Capital expenditures on property, plant and equipment											7,160	11,733	5,920
Long-lived assets of continuing operating activities	42,333						45,837				42,333	45,837	43,809
Total for reportable segments [Member]
Segment Reporting Information [Line Items]
Net Sales											588,541	575,337	467,058
Income from continuing operations, before income taxes											29,787	41,857	36,210
Assets	291,718						291,651				291,718	291,651	296,591
Depreciation and amortization											12,454	11,541	8,853
Capital expenditures on property, plant and equipment											6,004	10,938	5,035
Other net sales [Member]
Segment Reporting Information [Line Items]
Net Sales											0	0	0
Adjustment of inventory to LIFO [Member]
Segment Reporting Information [Line Items]
Income from continuing operations, before income taxes											1,118	(2,183)	2,276
Unallocated interest income [Member]
Segment Reporting Information [Line Items]
Income from continuing operations, before income taxes											452	321	403
Unallocated equity in income/(losses) of nonconsolidated investments [Member]
Segment Reporting Information [Line Items]
Income from continuing operations, before income taxes											837	707	(213)
Unallocated acquisition costs [Member]
Segment Reporting Information [Line Items]
Income from continuing operations, before income taxes													(2,413)
Unallocated gain on sale of marketable securities [Member]
Segment Reporting Information [Line Items]
Income from continuing operations, before income taxes													1,364
Unallocated corporate amounts [Member]
Segment Reporting Information [Line Items]
Income from continuing operations, before income taxes											(8,364)	(8,050)	(5,663)
Unallocated corporate assets [Member]
Segment Reporting Information [Line Items]
Assets	117,639						92,888				117,639	92,888	84,294
LIFO and corporate inventory reserves [Member]
Segment Reporting Information [Line Items]
Assets	(9,235)						(10,443)				(9,235)	(10,443)	(8,226)
Unallocated property, plant and equipment [Member]
Segment Reporting Information [Line Items]
Assets	6,000						5,798				6,000	5,798	5,743
Other - Segment Reporting [Member]
Segment Reporting Information [Line Items]
Depreciation and amortization											519	466	366
Expenditures financed under capital leases [Member]
Segment Reporting Information [Line Items]
Capital expenditures on property, plant and equipment													199
Other Expenditures [Member]
Segment Reporting Information [Line Items]
Capital expenditures on property, plant and equipment											1,156	795	686
Rail distribution products [Member]
Segment Reporting Information [Line Items]
Net Sales											155,832	115,777	102,155
Piling Products [Member]
Segment Reporting Information [Line Items]
Net Sales											114,070	162,641	146,703
Rail Technologies products [Member]
Segment Reporting Information [Line Items]
Net Sales											92,826	97,775	4,556
CXT concrete tie products [Member]
Segment Reporting Information [Line Items]
Net Sales											58,182	48,968	53,518
CXT concrete building products [Member]
Segment Reporting Information [Line Items]
Net Sales											30,195	35,557	60,091
Other products [Member]
Segment Reporting Information [Line Items]
Net Sales											137,436	114,619	100,035
United States [Member]
Segment Reporting Information [Line Items]
Net Sales											485,111	483,889	443,547
Long-lived assets of continuing operating activities	31,961						35,918				31,961	35,918	33,535
Canada [Member]
Segment Reporting Information [Line Items]
Net Sales											40,892	41,252	9,862
Long-lived assets of continuing operating activities	9,773						9,374				9,773	9,374	9,785
United Kingdom [Member]
Segment Reporting Information [Line Items]
Net Sales											18,698	14,728	627
Long-lived assets of continuing operating activities	599						545				599	545	489
Other - Seg Reporting [Member]
Segment Reporting Information [Line Items]
Net Sales											$ 43,840	$ 35,468	$ 13,022

[1] Includes a pre-tax loss of approximately $315,000 from the Company’s sale of Precise

[2] Includes a pre-tax gain of approximately $3,508,000 from the Company’s sale of SSD.