The current period expense charged against earnings on long-lived, physical assets not used in production, and which are not intended for resale, to allocate or recognize the cost of such assets over their useful lives; or to record the reduction in book value of an intangible asset over the benefit period of such asset; or to reflect consumption during the period of an asset that is not used in production.

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Segment Information - Segment Information Report of Statements of Operations (Detail) (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	$ 102,158us-gaap_SalesRevenueNet	$ 116,505us-gaap_SalesRevenueNet	$ 101,988us-gaap_SalesRevenueNet	$ 82,647us-gaap_SalesRevenueNet	$ 85,641us-gaap_SalesRevenueNet	$ 78,527us-gaap_SalesRevenueNet	$ 87,942us-gaap_SalesRevenueNet	$ 107,335us-gaap_SalesRevenueNet	$ 403,298us-gaap_SalesRevenueNet	$ 359,445us-gaap_SalesRevenueNet	$ 388,902us-gaap_SalesRevenueNet
Gross profit from continuing operations	9,125us-gaap_GrossProfit	15,820us-gaap_GrossProfit	11,317us-gaap_GrossProfit	4,314us-gaap_GrossProfit	10,853us-gaap_GrossProfit	11,254us-gaap_GrossProfit	15,210us-gaap_GrossProfit	22,919us-gaap_GrossProfit	40,576us-gaap_GrossProfit	60,236us-gaap_GrossProfit	59,108us-gaap_GrossProfit
Operating income (loss) from continuing operations	(13,410)us-gaap_OperatingIncomeLoss	9,331us-gaap_OperatingIncomeLoss	5,399us-gaap_OperatingIncomeLoss	(1,126)us-gaap_OperatingIncomeLoss	5,679us-gaap_OperatingIncomeLoss	5,698us-gaap_OperatingIncomeLoss	9,269us-gaap_OperatingIncomeLoss	16,889us-gaap_OperatingIncomeLoss	194us-gaap_OperatingIncomeLoss	37,535us-gaap_OperatingIncomeLoss	31,286us-gaap_OperatingIncomeLoss
Depreciation and amortization of property and equipment									14,146us-gaap_DepreciationAndAmortization	13,299us-gaap_DepreciationAndAmortization	16,267us-gaap_DepreciationAndAmortization
Capital expenditures									14,289	28,447	16,789
Operating Segments [Member]
Segment Reporting Information [Line Items]
Operating income (loss) from continuing operations									14,813	52,286	48,339
Depreciation and amortization of property and equipment									13,806	13,045	16,015
Capital expenditures									13,716	27,558	16,643
Corporate [Member]
Segment Reporting Information [Line Items]
Operating income (loss) from continuing operations	(4,000)	(3,943)	(3,555)	(3,121)	(3,309)	(3,559)	(4,004)	(3,879)	(14,619)	(14,751)	(17,053)
Depreciation and amortization of property and equipment									340	254	252
Capital expenditures									573	889	146
Reportable Geographical Components [Member] \| United States [Member]
Segment Reporting Information [Line Items]
Net sales									383,344	308,345	332,859
Reportable Geographical Components [Member] \| Non US [Member]
Segment Reporting Information [Line Items]
Net sales									19,954	51,100	56,043
Water Transmission [Member] \| Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales	56,484	76,857	62,205	42,999	42,831	46,835	58,148	78,613	238,545	226,427	269,203
Gross profit from continuing operations	9,883	16,559	11,491	1,668	7,026	7,932	12,125	19,870	39,601	46,953	45,051
Operating income (loss) from continuing operations	7,817	14,429	9,543	(299)	5,505	6,306	10,499	18,033	31,490	40,343	36,278
Depreciation and amortization of property and equipment									8,716	7,082	10,474
Capital expenditures									6,190	13,204	6,830
Tubular Products [Member] \| Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales	45,674	39,648	39,783	39,648	42,810	31,692	29,794	28,722	164,753	133,018	119,699
Gross profit from continuing operations	(758)	(739)	(174)	2,646	3,827	3,322	3,085	3,049	975	13,283	14,057
Operating income (loss) from continuing operations	(17,227)	(1,155)	(589)	2,294	3,483	2,951	2,774	2,735	(16,677)	11,943	12,061
Depreciation and amortization of property and equipment									5,090	5,963	5,541
Capital expenditures									$ 7,526	$ 14,354	$ 9,813