Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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The aggregate net amount of depreciation, amortization, and accretion recognized during an accounting period. As a noncash item, the net amount is added back to net income when calculating cash provided by or used in operations using the indirect method.

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Aggregate revenue during the period from the sale of goods in the normal course of business, after deducting returns, allowances and discounts.

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Business Segments (Reconciliation of Significant Reconciling Items) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Net sales	$ 161,149us-gaap_SalesRevenueGoodsNet	$ 167,797us-gaap_SalesRevenueGoodsNet	$ 166,832us-gaap_SalesRevenueGoodsNet	$ 111,414us-gaap_SalesRevenueGoodsNet	$ 156,458us-gaap_SalesRevenueGoodsNet	$ 162,248us-gaap_SalesRevenueGoodsNet	$ 149,936us-gaap_SalesRevenueGoodsNet	$ 129,321us-gaap_SalesRevenueGoodsNet	$ 607,192us-gaap_SalesRevenueGoodsNet	$ 597,963us-gaap_SalesRevenueGoodsNet	$ 588,541us-gaap_SalesRevenueGoodsNet
Segment Assets	495,121us-gaap_Assets				413,654us-gaap_Assets				495,121us-gaap_Assets	413,654us-gaap_Assets	406,122us-gaap_Assets
Depreciation and amortization									12,577	10,002	12,973
Expenditures for Long-Lived Assets									19,037	9,674	7,160
Rail Products Segment [Member]
Segment Reporting Information [Line Items]
Net sales									374,615	363,667	370,322
Segment Profit									30,093	28,692	9,074
Segment Assets	239,951				252,049				239,951	252,049	243,072
Depreciation and amortization									6,153	6,505	9,736
Expenditures for Long-Lived Assets									5,115	3,383	4,180
Construction Products Segment [Member]
Segment Reporting Information [Line Items]
Net sales									178,847	191,751	169,253
Segment Profit									13,106	10,206	7,859
Segment Assets	102,978				77,900				102,978	77,900	73,804
Depreciation and amortization									2,232	1,758	2,119
Expenditures for Long-Lived Assets									3,343	1,805	474
Tubular Products Segments [Member]
Segment Reporting Information [Line Items]
Net sales									53,730	42,545	48,966
Segment Profit									5,350	9,208	12,854
Segment Assets	130,289				51,497				130,289	51,497	13,573
Depreciation and amortization									3,208	1,054	599
Expenditures for Long-Lived Assets									6,988	2,460	1,350
Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales									607,192	597,963	588,541
Segment Profit									48,549	48,106	29,787
Segment Assets	473,218				381,446				473,218	381,446	330,449
Depreciation and amortization									11,593	9,317	12,454
Expenditures for Long-Lived Assets									$ 15,446	$ 7,648	$ 6,004