Northwest Pipe (NWPX) 10-Q 9 May 14 2014 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
	Mar. 31, 2014	6-May-14
Document And Entity Information [Abstract]	'	'
Document Type	'10-Q	'
Amendment Flag	'false	'
Document Period End Date	31-Mar-14	'
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q1	'
Trading Symbol	'NWPX	'
Entity Registrant Name	'NORTHWEST PIPE CO	'
Entity Central Index Key	'0001001385	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	9,508,917

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Current assets:	'	'
Cash and cash equivalents	$49	$588
Trade and other receivables, less allowance for doubtful accounts of $473 and $685	57,482	72,470
Costs and estimated earnings in excess of billings on uncompleted contracts	44,328	50,468
Inventories	62,974	110,392
Refundable income taxes	11,474	1,073
Deferred income taxes	4,137	6,208
Prepaid expenses and other	2,156	2,381
Total current assets	182,600	243,580
Property and equipment, net	133,303	143,061
Goodwill	21,348	25,760
Other assets	25,345	21,058
Total assets	362,596	433,459
Current liabilities:	'	'
Current portion of long-term debt	3,571	5,714
Current portion of capital lease obligations	950	2,216
Accounts payable	20,924	21,731
Accrued liabilities	12,192	15,194
Billings in excess of costs and estimated earnings on uncompleted contracts	18,215	3,368
Total current liabilities	55,852	48,223
Note payable to financial institution	25,191	87,919
Long-term debt, less current portion	'	643
Capital lease obligations, less current portion	1,357	5,679
Deferred income taxes	12,879	11,842
Pension and other long-term liabilities	16,219	17,303
Total liabilities	111,498	171,609
Commitments and contingencies (Note 6)	'	'
Stockholders' equity:	'	'
Preferred stock, $.01 par value, 10,000,000 shares authorized, none issued or outstanding	'	'
Common stock, $.01 par value, 15,000,000 shares authorized, 9,508,917 and 9,449,299 shares issued and outstanding	95	94
Additional paid-in-capital	113,630	114,559
Retained earnings	138,568	148,458
Accumulated other comprehensive loss	-1,195	-1,261
Total stockholders' equity	251,098	261,850
Total liabilities and stockholders' equity	$362,596	$433,459

Condensed_Consolidated_Balance1

Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, except Share data, unless otherwise specified
Statement Of Financial Position [Abstract]	'	'
Trade and other receivables, allowance for doubtful accounts	$473	$685
Preferred stock, par value	$0.01	$0.01
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	'	'
Preferred stock, shares outstanding	'	'
Common stock, par value	$0.01	$0.01
Common stock, shares authorized	15,000,000	15,000,000
Common stock, shares issued	9,508,917	9,449,299
Common stock, shares outstanding	9,508,917	9,449,299

Condensed_Consolidated_Stateme

Condensed Consolidated Statements of Operations (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Income Statement [Abstract]	'	'
Net sales	$82,647	$107,335
Cost of sales	78,333	84,416
Gross profit	4,314	22,919
Selling, general and administrative expense	5,440	6,030
Operating income (loss)	-1,126	16,889
Other expense	63	41
Interest income	-81	-183
Interest expense	770	957
Income (loss) before income taxes	-1,878	16,074
Provision for (benefit from) income taxes	-667	5,098
Net income from continuing operations	-1,211	10,976
Discontinued operations:	'	'
Loss from discontinued operations	-2,662	-2,160
Loss on sale of business	-12,083	'
Benefit from income taxes	-6,066	-690
Net loss from discontinued operations	-8,679	-1,470
Net income (loss)	($9,890)	$9,506
Basic earnings (loss) per share:	'	'
Continuing operations	($0.13)	$1.16
Discontinued operations	($0.91)	($0.15)
Total	($1.04)	$1.01
Diluted earnings (loss) per share:	'	'
Continuing operations	($0.13)	$1.16
Discontinued operations	($0.91)	($0.16)
Total	($1.04)	$1
Shares used in per share calculations:	'	'
Basic	9,508	9,437
Diluted	9,508	9,484

Condensed_Consolidated_Stateme1

Condensed Consolidated Statements of Comprehensive Income (Loss) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Statement Of Income And Comprehensive Income [Abstract]	'	'
Net income (loss)	($9,890)	$9,506
Other comprehensive income:	'	'
Pension liability adjustment, net of tax	64	65
Deferred gain on cash flow derivatives, net of tax	2	111
Other comprehensive income	66	176
Comprehensive income (loss)	($9,824)	$9,682

Condensed_Consolidated_Stateme2

Condensed Consolidated Statements of Cash Flows (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Cash Flows From Operating Activities:	'	'
Net income (loss)	($9,890)	$9,506
Adjustments to reconcile net income (loss) to net cash provided by operating activities:	'	'
Depreciation and amortization	3,166	3,865
Amortization of intangible assets	131	'
Provision for doubtful accounts	-212	51
Amortization of debt issuance costs	134	158
Loss on impairment	25	'
Deferred income taxes	3,108	649
Gain on disposal of property and equipment	'	-177
Loss on sale of business	12,083	'
Stock based compensation expense	354	526
Unrealized gain on foreign currency forward contracts	-36	-94
Changes in operating assets and liabilities:	'	'
Trade and other receivables, net	9,725	-23,968
Costs and estimated earnings in excess of billings on uncompleted contracts, net	20,987	-390
Inventories	14,477	4,085
Refundable income taxes	-10,401	'
Prepaid expenses and other assets	-2	387
Accounts payable	577	10,728
Accrued and other liabilities	-4,087	-1,482
Net cash provided by operating activities	40,139	3,844
Cash Flows From Investing Activities:	'	'
Additions to property and equipment	-4,964	-9,781
Proceeds from sale of business	31,609	'
Proceeds from the sale of property and equipment	'	1,669
Restricted cash	'	'
Other investing activities	13	'
Net cash provided by (used in) investing activities	26,658	-8,112
Cash Flows From Financing Activities:	'	'
Tax withholdings related to net share settlements of restricted stock awards and performance shares	-1,283	-802
Payments on long-term debt	-2,786	-2,786
Borrowings under note payable to financial institution	23,831	37,471
Payments on note payable to financial institution	-86,559	-28,768
Payments on capital lease obligations	-539	-846
Net cash provided by (used in) financing activities	-67,336	4,269
Change in cash and cash equivalents	-539	1
Cash and cash equivalents, beginning of period	588	46
Cash and cash equivalents, end of period	49	47
Non-Cash Investing Activity:	'	'
Escrow account related to capital lease financing	'	898
Accrued property and equipment purchases	$1,127	$4,605

Basis_of_Presentation

Basis of Presentation	3 Months Ended
	Mar. 31, 2014
Accounting Policies [Abstract]	'
Basis of Presentation	'
	1	Basis of Presentation
	The condensed consolidated financial statements include the accounts of Northwest Pipe Company (the “Company”) and its subsidiaries in which the Company exercises control as of the financial statement date. Intercompany accounts and transactions have been eliminated.
	The accompanying unaudited condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America. The financial information as of December 31, 2013 is derived from the audited consolidated financial statements presented in the Company’s Annual Report on Form 10-K for the year ended December 31, 2013 (the “2013 Form 10-K”). Certain information or footnote disclosures normally included in consolidated financial statements prepared in accordance with accounting principles generally accepted in the United States of America have been condensed or omitted, pursuant to the rules and regulations of the Securities and Exchange Commission (the “SEC”). In the opinion of management, the accompanying condensed consolidated financial statements include all adjustments necessary (which are of a normal and recurring nature) for the fair statement of the results of the interim periods presented. The condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and notes thereto together with management’s discussion and analysis of financial condition and results of operations contained in the Company’s 2013 Form 10-K.
	On March 30, 2014 the Company completed the sale of substantially all of the assets and liabilities associated with the oil country tubular goods (“OCTG”) business. See Note 2, “Acquisitions and Disposals” for further information regarding the sale. The Company’s results of operations for its disposed OCTG business have been presented as discontinued operations for all periods presented within the condensed consolidated statements of operations.
	Operating results for the three months ended March 31, 2014 are not necessarily indicative of the results that may be expected for the entire fiscal year ending December 31, 2014.

Acquisitions_and_Disposals

Acquisitions and Disposals	3 Months Ended
	Mar. 31, 2014
Business Combinations [Abstract]	'
Acquisitions and Disposals	'
	2	Acquisitions and Disposals
	Disposal of OCTG Business
	On March 30, 2014 the Company completed the sale of substantially all of the assets and liabilities associated with the OCTG business conducted by the Company at its manufacturing facilities in Bossier City, Louisiana and Houston, Texas, excluding the real property located in Houston, Texas. These facilities were previously included within the Company’s Tubular Products Group. Total consideration of $42.7 million was paid by the buyer, resulting in a loss on sale of $12.1 million. The calculation of the loss on sale included a writedown of $4.4 million of goodwill. Of the proceeds received, $4.3 million was placed in escrow to secure the Company’s indemnification obligations under the purchase agreement, $5.0 million was used to repay capital leases related to and secured by certain assets at the Bossier City, Louisiana manufacturing facility, and $1.8 million was used to pay for transaction costs, resulting in net proceeds paid to the Company at closing of $31.6 million. A purchase price adjustment related to working capital is expected to occur by June 30, 2014. In connection with the sale, the Company and the purchaser entered into a six month lease of the real property located in Houston, Texas and the Company granted the purchaser an option to purchase the property under certain circumstances.
	The table below presents the components of the balance sheet accounts associated with the OCTG business as of December 31, 2013, in thousands. All assets and liabilities were transferred to the buyer as of March 30, 2014.
			December 31,
			2013
	Assets:
	Trade and other receivables, net		$	11,673
	Inventories			44,668
	Prepaid expenses and other			206
	Total current assets			56,547
	Property and equipment, net			11,509
	Total assets			68,056
	Liabilities:
	Current portion of capital lease obligations			1,289
	Accounts payable			3,013
	Accrued liabilities			1,466
	Deferred revenue			4,505
	Total current liabilities			10,273
	Capital lease obligations, less current portion			4,075
	Total liabilities		$	14,348
	The table below presents the operating results for the Company’s discontinued operations (in thousands). These operating results for the three months ended March 31, 2014 do not necessarily reflect what they would have been had the OCTG business not been classified as a discontinued operation.
			Three Months Ended March 31,
			2014			2013
	Net sales		$	22,225		$	33,261
	Cost of sales			24,393			34,976
	Gross loss			(2,167	)		(1,715	)
	Selling, general and administrative expense			396			353
	Operating loss			(2,563	)		(2,068	)
	Interest expense			99			92
	Loss on sale of discontinued operations			12,083			—
	Loss before income taxes			(14,745	)		(2,160	)
	Benefit from income taxes			(6,066	)		(690	)
	Net loss from discontinued operations		$	(8,679	)	$	(1,470	)
	Acquisition of Permalok Corporation
	On December 30, 2013 the Company acquired 100% of the outstanding shares of capital stock of Permalok Corporation (“Permalok”), a fabricator of steel piping utilizing the Permalok interlocking pipe joining system. Total consideration (net of cash received) of $15.7 million was paid to the owners of the business, resulting in the recording of $5.3 million of goodwill, none of which is expected to be deductible for tax purposes. Contingent consideration of $1.4 million and $3.1 million is recorded in accrued liabilities and other long-term liabilities as of March 31, 2014, respectively. Contingent consideration was estimated based on the present value of the probability weighted revenue projections for the three fiscal years following the acquisition date.

Inventories

Inventories	3 Months Ended
	Mar. 31, 2014
Inventory Disclosure [Abstract]	'
Inventories	'
	3	Inventories
	Inventories are stated at the lower of cost or market and consist of the following (in thousands):
			March 31,		December 31,
			2014		2013
	Short-term inventories:
	Raw materials		$	43,061	$	52,598
	Work-in-process			3,261		4,902
	Finished goods			14,364		49,351
	Supplies			2,288		3,541
				62,974		110,392
	Long-term inventories:
	Finished goods			1,208		1,249
	Total inventories		$	64,182	$	111,641
	Long-term inventories are recorded in other assets.

Fair_Value_Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2014
Fair Value Disclosures [Abstract]	'
Fair Value Measurements	'
	4	Fair Value Measurements
	The Company records its financial assets and liabilities at fair value, which is defined as the price that would be received to sell an asset or paid to transfer a liability, in the principal or most advantageous market for the asset or liability, in an orderly transaction between market participants at the measurement date.
	The authoritative guidance establishes a fair value hierarchy which prioritizes the inputs to valuation techniques used to measure fair value into three broad levels. These levels are: Level 1 (inputs are quoted prices in active markets for identical assets or liabilities); Level 2 (inputs are other than quoted prices that are observable, either directly or indirectly through corroboration with observable market data); and Level 3 (inputs are unobservable, with little or no market data that exists, such as internal financial forecasts). The Company is required to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value.
	The following table summarizes information regarding the Company’s financial assets and financial liabilities that are measured at fair value (in thousands):
	Description		Balance at			Level 1		Level 2			Level 3
			March 31,
			2014
	Financial Assets
	Non-qualified retirement savings plan assets		$	6,102		$	4,975	$	1,127		$	—
	Derivatives			107			—		107			—
	Total Assets		$	6,209		$	4,975	$	1,234		$	—
	Financial Liabilities
	Contingent consideration		$	(4,486	)	$	—	$	—		$	(4,486	)
	Derivatives			(68	)		—		(68	)		—
	Total Liabilities		$	(4,554	)	$	—	$	(68	)	$	(4,486	)
	Description		Balance at			Level 1		Level 2			Level 3
			December 31,
			2013
	Financial Assets
	Non-qualified retirement savings plan assets		$	6,000		$	4,944	$	1,056		$	—
	Derivatives			1			—		1			—
	Total Assets		$	6,001		$	4,944	$	1,057		$	—
	Financial Liabilities
	Contingent consideration		$	(4,425	)	$	—	$	—		$	(4,425	)
	Derivatives			(1	)		—		(1	)		—
	Total Liabilities		$	(4,426	)	$	—	$	(1	)	$	(4,425	)
	The non-qualified retirement savings plan assets consist of cash and several publicly traded stock and bond mutual funds, valued using quoted market prices in active markets classified as Level 1 within the fair value hierarchy, as well as securities that are not actively traded on major exchanges, valued using the NAV of the underlying investments classified as Level 2 within the fair value hierarchy. The Company’s derivatives consist of foreign currency forward contracts, which are accounted for as cash flow hedges, and are valued using various pricing models or discounted cash flow analyses that incorporate observable market parameters, such as interest rate yield curves and currency rates, classified as Level 2 within the valuation hierarchy. Derivative valuations incorporate credit risk adjustments that are necessary to reflect the probability of default by the counterparty or the Company.
	The fair value of contingent consideration was estimated based on the present value of the probability weighted revenue projections for the three fiscal years following the acquisition date of Permalok. The inputs used to measure contingent consideration are classified as Level 3 within the valuation hierarchy. The valuation is not supported by market criteria and reflects the Company’s internal revenue forecasts. The discount rate used in the analysis was 5.3%. Changes in the fair value of the contingent consideration payment are reflected in earnings during the period which the change in the estimated fair value is calculated.
	The net carrying amounts of cash and cash equivalents, trade and other receivables, accounts payable, accrued liabilities and note payable to financial institution approximate fair value due to the short-term nature of these instruments. The fair value of our debt is calculated using a coupon rate on borrowings with similar maturities, current remaining average life to maturity, borrower credit quality, and current market conditions, all of which are classified as Level 2 within the valuation hierarchy. The fair value of the Company’s long-term debt, including the current portion, was $3.5 million and the carrying value was $3.6 million at March 31, 2014, and $6.3 million with a carrying value of $6.4 million at December 31, 2013.

Derivative_Instruments_and_Hed

Derivative Instruments and Hedging Activities	3 Months Ended
	Mar. 31, 2014
Derivative Instruments And Hedging Activities Disclosure [Abstract]	'
Derivative Instruments and Hedging Activities	'
	5	Derivative Instruments and Hedging Activities
	The Company conducts business in various foreign countries and, from time to time, settles transactions in foreign currencies. The Company has established a program that utilizes foreign currency forward contracts to offset the risk associated with the effects of certain foreign currency exposures, typically arising from sales contracts denominated in Canadian currency. Instruments that do not qualify for cash flow hedge accounting treatment are remeasured at fair value on each balance sheet date and resulting gains and losses are recognized in net income. As of March 31, 2014, all derivative contracts were designated as hedges. As of December 31, 2013 the total notional amount of the derivative contracts not designated as hedges was $0.1 million (CAD$0.1 million). As of March 31, 2014 and December 31, 2013, the total notional amount of the derivative contracts designated as hedges was $5.4 million (CAD$6.0 million) and $3.8 million (CAD$4.1 million), respectively. Derivative assets are included within prepaid expenses and other and derivative liabilities are included within accrued liabilities in the condensed consolidated balance sheets. All of the Company’s foreign currency forward contracts are subject to an enforceable master netting arrangement. The Company presents its foreign currency forward contract assets and liabilities within the condensed consolidated balance sheets at their gross fair values.
	For each derivative contract entered into in which the Company seeks to obtain cash flow hedge accounting treatment, the Company formally documents all relationships between hedging instruments and hedged items, as well as its risk management objective and strategy for undertaking the hedge transaction, the nature of the risk being hedged, how the hedging instrument’s effectiveness in offsetting the hedged risk will be assessed prospectively and retrospectively, and a description of the method of measuring ineffectiveness. This process includes linking all derivatives to specific firm commitments or forecasted transactions and designating the derivatives as cash flow hedges. The Company also formally assesses, both at the hedge’s inception and on an ongoing basis, whether the derivative contracts that are used in hedging transactions are highly effective in offsetting changes in cash flows of hedged items. The effective portion of these hedged items is reflected in other comprehensive income in stockholders’ equity. If it is determined that a derivative contract is not highly effective, or that it has ceased to be a highly effective hedge, the Company will be required to discontinue hedge accounting with respect to that derivative contract prospectively.
	All of the Company’s Canadian forward contracts have maturities not longer than 12 months as of March 31, 2014.
	For the three months ended March 31, 2014 and March 31, 2013, gains (losses) from derivative contracts not designated as hedging instruments recognized in net sales were $0.1 million and ($0.1) million, respectively. At March 31, 2014, there is $0.1 million of unrealized pretax gain on outstanding derivatives accumulated in other comprehensive loss, substantially all of which is expected to be reclassified to net sales within the next 12 months as a result of underlying hedged transactions also being recorded in net sales. See Note 11, “Accumulated Other Comprehensive Income (Loss)” for additional quantitative information regarding derivative gains and losses.

Commitments_and_Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2014
Commitments And Contingencies Disclosure [Abstract]	'
Commitments and Contingencies	'
	6	Commitments and Contingencies
	Portland Harbor Superfund
	On December 1, 2000, a section of the lower Willamette River known as the Portland Harbor was included on the National Priorities List at the request of the United States Environmental Protection Agency (the “EPA”). While the Company’s Portland, Oregon manufacturing facility does not border the Willamette River, an outfall from the facility’s stormwater system drains into a neighboring property’s privately owned stormwater system and slip. Since the listing of the site, the Company was notified by the EPA and the Oregon Department of Environmental Quality (the “ODEQ”) of potential liability under the Comprehensive Environmental Response, Compensation and Liability Act (“CERCLA”). In 2008, the Company was asked to file information disclosure reports with the EPA (CERCLA 104 (e) information request). By agreement with the EPA, the ODEQ is responsible for overseeing remedial investigation and source control activities for all upland sites to investigate sources and prevent future contamination to the river. A remedial investigation and feasibility study (“RI/FS”) of the Portland Harbor has been directed by a group of 14 potentially responsible parties known as the Lower Willamette Group (the “LWG”) under agreement with the EPA. The Company made a payment of $175,000 to the LWG in June 2007 as part of an interim settlement, and is under no obligation to make any further payment. The final draft remedial investigation (“RI”) was submitted to the EPA by the LWG in fall of 2011 and the draft feasibility study (“FS”) was submitted by the LWG to the EPA in March 2012. The draft FS identifies ten possible remedial alternatives which range in estimated cost from approximately $169 million to $1.76 billion and estimates a range of two to 28 years to implement the remedial work, depending on the selected alternative. The report does not determine who is responsible for the costs of cleanup or how the cleanup costs will be allocated among the potentially responsible parties. As of the date of this filing, the final RI and the revised FS are pending submittal to the EPA.
	In 2001, groundwater containing elevated volatile organic compounds (“VOCs”) was identified in one localized area of leased property adjacent to the Portland facility furthest from the river. Assessment work in 2002 and 2003 to further characterize the groundwater was consistent with the initial conclusion that the source of the VOCs is located off of Company-owned property. In February 2005, the Company entered into a Voluntary Agreement for Remedial Investigation and Source Control Measures (the “Agreement”) with the ODEQ. The Company is one of many Upland Source Control Sites working with the ODEQ on Source Control and is considered a “medium” priority site by the ODEQ indicating more investigation was recommended. The Company performed RI work required under the Agreement and submitted a draft RI/Source Control Evaluation Report (“SCE”) in December 2005 and a revised draft RI/SCE Report in January 2014 (2014 RI/SCE Report). The conclusions of the report include: (1) the VOCs found in the groundwater do not present an unacceptable risk to human or ecological receptors in the Willamette River; (2) there is no evidence at this time showing a connection between detected VOCs in groundwater and Willamette River sediments. (3) the interim remedial measure to conduct a limited excavation of soil and complete paving the site was completed; (4) a state-of-the art- stormwater treatment system was installed; and (5) an area of stained soil was characterized and remediated.
	During the localized soil excavation in 2011, additional stained soil was discovered. At the request of the ODEQ, the Company developed an additional Work Plan to characterize the nature and extent of soil and/or groundwater impacts from the staining. The Company began implementing this Work Plan in the second quarter of 2012 and submitted sampling results to the ODEQ in the third quarter of 2012. Comments from the ODEQ were received in November 2012. In February 2013, the ODEQ clarified its comments from November 2012, and the Company has completed its second round of groundwater sampling for the Stained Soil Investigation Area in May and November 2013. The results were reported to ODEQ in January 2014 in the RI/SCE Report.
	The Company anticipates having to spend less than $0.1 million for further Source Control work in 2014.
	Concurrent with the activities of the EPA and the ODEQ, the Portland Harbor Natural Resources Trustee Council (“Trustees”) sent some or all of the same parties, including the Company, a notice of intent to perform a Natural Resource Damage Assessment (“NRDA”) for the Portland Harbor Site to determine the nature and extent of natural resource damages under CERCLA section 107. The Trustees for the Portland Harbor Site consist of representatives from several Northwest Indian Tribes, three federal agencies and one state agency. The Trustees act independently of the EPA and the ODEQ. The Trustees have encouraged potentially responsible parties to voluntarily participate in the funding of their injury assessments and several of those parties have agreed to do so. The Company has not assumed any payment obligation or liability related to this request.
	The Company’s potential liability is a portion of the costs of the remedy the EPA will select for the entire Portland Harbor Superfund site. The cost of that remedy is expected to be allocated among more than 100 potentially responsible parties. Because of the large number of responsible parties and the variability in the range of remediation alternatives, the Company is unable to estimate an amount or an amount within a range of costs for its obligation with respect to the Portland Harbor matters, and no further adjustment to the condensed consolidated financial statements has been recorded as of the date of this filing. The Company has insurance policies for defense costs, as well indemnification policies it believes will provide reimbursement for any share of the remediation assessed. However, the Company can provide no assurance that those policies will cover all of the costs which the Company may incur.
	Houston Environmental Cleanup
	In connection with the Company’s review of strategic direction concerning its OCTG assets, a Limited Phase II Environmental Site Assessment was conducted at the Houston, Texas plant and completed in March 2014 which revealed the presence of VOCs in the groundwater and certain metals in the soil. On April 9, 2014, the Company applied for admission into the Texas Commission on Environmental Quality (“TCEQ”) Voluntary Cleanup Program to address these issues and obtain a Certificate of Completion from TCEQ. The cost of any potential cleanup will not be covered by insurance. However, any costs incurred will be reimbursed by the purchaser of the OCTG business discussed in Note 2, “Acquisitions and Disposals” if the purchaser of the OCTG business exercises its option to purchase the property under certain circumstances after the Certificate of Completion is obtained. As the Company is in the early stages of this process, no adjustment to the condensed consolidated financial statements has been recorded as of the date of this filing.
	All Sites
	The Company operates its facilities under numerous governmental permits and licenses relating to air emissions, storm water run-off, and other environmental matters. The Company’s operations are also governed by many other laws and regulations, including those relating to workplace safety and worker health, principally the Occupational Safety and Health Act and regulations there under which, among other requirements, establish noise and dust standards. The Company believes it is in material compliance with its permits and licenses and these laws and regulations, and the Company does not believe that future compliance with such laws and regulations will have a material adverse effect on its financial position, results of operations or cash flows.
	From time to time, the Company is involved in litigation relating to claims arising out of its operations in the normal course of its business. The Company maintains insurance coverage against potential claims in amounts that are believed to be adequate. The Company believes that it is not presently a party to any other litigation, the outcome of which would have a material adverse effect on its business, financial condition, results of operations or cash flows.
	Guarantees
	The Company has entered into certain stand-by letters of credit that total $3.1 million at March 31, 2014. The stand-by letters of credit relate to workers’ compensation insurance and equipment financing.

Segment_Information

Segment Information	3 Months Ended
	Mar. 31, 2014
Segment Reporting [Abstract]	'
Segment Information	'
	7	Segment Information
	The Company’s operations are organized in two reportable segments, the Water Transmission Group and the Tubular Products Group, which are based on the nature of the products and the manufacturing process. The Water Transmission Group manufactures large-diameter, high-pressure steel pipeline systems for use in water infrastructure applications, primarily related to drinking water systems. These products are also used for hydroelectric power systems, wastewater systems and other applications. In addition, the Water Transmission Group makes products for industrial plant piping systems and certain structural applications. The Tubular Products Group manufactures and markets smaller diameter, electric resistance welded steel pipe used in a wide range of applications, including energy, construction, agriculture and industrial systems. These two segments represent distinct business activities, which management evaluates based on segment gross profit and operating income. Transfers between segments in the periods presented were not material.
	The Tubular Products Group also manufactured and marketed OCTG products through March 30, 2014. The operating results of the OCTG business have been classified as discontinued operations and are not included in the operating results presented below.
			Three months ended March 31,
			2014			2013
			(in thousands)
	Net sales:
	Water transmission		$	42,999		$	78,613
	Tubular products			39,648			28,722
	Total		$	82,647		$	107,335
	Gross profit:
	Water transmission		$	1,668		$	19,870
	Tubular products			2,646			3,049
	Total		$	4,314		$	22,919
	Operating income (loss):
	Water transmission		$	(299	)	$	18,033
	Tubular products			2,294			2,735
	Corporate			(3,121	)		(3,879	)
	Total		$	(1,126	)	$	16,889

Sharebased_Compensation

Share-based Compensation	3 Months Ended
	Mar. 31, 2014
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]	'
Share-based Compensation	'
	8	Share-based Compensation
	The Company has one active stock incentive plan for employees and directors, the 2007 Stock Incentive Plan, which provides for awards of stock options to purchase shares of common stock, stock appreciation rights, restricted and unrestricted shares of common stock, restricted stock units (RSUs) and performance share awards (PSAs). In addition, the Company has one inactive stock option plan, the 1995 Stock Option Plan for Nonemployee Directors, under which previously granted options remain outstanding.
	The Company recognizes compensation cost as service is rendered based on the fair value of the awards. The following summarizes share-based compensation expense recorded (in thousands):
			Three months ended March 31,
			2014			2013
	Cost of sales		$	11		$	128
	Selling, general and administrative expenses			343			398
	Total		$	354		$	526
	As of March 31, 2014, unrecognized compensation expense related to the unvested portion of the Company’s RSUs and PSAs was $3.1 million which is expected to be recognized over a weighted average period of 1.6 years.
	Stock Option Awards
	A summary of the status of the Company’s stock options as of March 31, 2014 and changes during the three months then ended is presented below:
			Options			Weighted		Weighted		Aggregate
			Outstanding			Average		Average		Intrinsic Value
						Exercise Price		Remaining
						per Share		Contractual
								Life
										(In thousands)
	Balance, January 1, 2014			40,000		$	25.44
	Options granted			—			—
	Options exercised or exchanged			—			—
	Options canceled			—			—
	Balance, March 31, 2014			40,000			25.44		4.4	$	429
	Exercisable, March 31, 2014			40,000			25.44		4.4	$	429
	Restricted Stock Units and Performance Awards
	A summary of the status of the Company’s RSUs and PSAs as of March 31, 2014 and changes during the three months then ended is presented below:
			Number of RSUs			Weighted Average
			and PSAs			Grant Date Fair Value
	Unvested RSUs and PSAs at January 1, 2014			257,087		$	30.69
	RSUs and PSAs granted			—			—
	RSUs and PSAs vested			(80,469	)		25.82
	RSUs and PSAs canceled			(21,625	)		31.47
	Unvested RSUs and PSAs at March 31, 2014			154,993			33.12
	RSUs and PSAs are measured at the estimated fair value on the date of grant. RSUs are service-based awards and vest according to vesting schedules, which range from immediate to ratably over a three-year period. PSAs are service-based awards with a market-based vesting condition. Vesting of the market-based PSAs is dependent upon the performance of the market price of the Company’s stock relative to a peer group of companies and ranges from two to three years. The unvested balance of RSUs and PSAs at March 31, 2014 includes approximately 129,000 PSAs at a target level of performance; the actual number of common shares that will ultimately be issued will be determined by multiplying this number of PSAs by a payout percentage ranging from 0% to 200%.

Income_Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2014
Income Tax Disclosure [Abstract]	'
Income Taxes	'
	9	Income Taxes
	The Company files income tax returns in the United States Federal jurisdiction, in a limited number of foreign jurisdictions, and in many state jurisdictions. Internal Revenue Service examinations have been completed for years prior to 2011, and with few exceptions, the Company is no longer subject to U.S. Federal, state or foreign income tax examinations for years before 2009.
	The Company had $2.9 million and $6.2 million of unrecognized tax benefits at March 31, 2014 and December 31, 2013, respectively. The Company believes it is reasonably possible that the total amounts of unrecognized tax benefits will decrease in the following twelve months due to statute requirements; however, actual results could differ from those currently expected. Of the balance of unrecognized tax benefits, $2.4 million would affect the Company’s effective tax rate if recognized at some point in the future.
	The Company recognizes interest and penalties related to uncertain tax positions in income tax expense. The Company provided for income taxes from continuing operations at estimated effective tax rates of 35.5% and 31.7% for the three month periods ended March 31, 2014 and March 31, 2013, respectively.

Earnings_per_Share

Earnings per Share	3 Months Ended
	Mar. 31, 2014
Earnings Per Share [Abstract]	'
Earnings per Share	'
	10	Earnings per Share
	Earnings per basic and diluted weighted average common share outstanding for continuing and discontinued operations were calculated as follows for the three months ended March 31, 2014 and 2013 (in thousands, except per share data):
			Three Months Ended March 31,
			2014			2013
	Net income (loss) from continuing operations		$	(1,211	)	$	10,976
	Net loss from discontinued operations			(8,679	)		(1,470	)
	Net income (loss)		$	(9,890	)	$	9,506
	Basic weighted-average common shares outstanding			9,508			9,437
	Effect of potentially dilutive common shares(1)			—			47
	Diluted weighted-average common shares outstanding			9,508			9,484
	Earnings (loss) per basic common share
	Continuing operations			(0.13	)		1.16
	Discontinued operations			(0.91	)		(0.15	)
	Total		$	(1.04	)	$	1.01
	Earnings (loss) per diluted common share
	Continuing operations			(0.13	)		1.16
	Discontinued operations			(0.91	)		(0.16	)
	Total		$	(1.04	)	$	1
	Antidilutive shares not included in diluted common share calculation			—			10
	-1	Represents the effect of the assumed exercise of stock options and the vesting of restricted stock units and performance stock awards, based on the treasury stock method.

Accumulated_Other_Comprehensiv

Accumulated Other Comprehensive Income (Loss)	3 Months Ended
	Mar. 31, 2014
Equity [Abstract]	'
Accumulated Other Comprehensive Income (Loss)	'
	11	Accumulated Other Comprehensive Income (Loss)
	The following table summarizes changes in the components of accumulated other comprehensive income (loss) during the three months ended March 31, 2014 (in thousands). All amounts are net of tax:
			Defined Benefit			Gains (Losses) on			Total
			Pension Items			Cash Flow
						Hedges
	Balance, December 31, 2013		$	(1,275	)	$	14		$	(1,261	)
	Other comprehensive income before reclassifications			36			9			45
	Amounts reclassified from accumulated other comprehensive income (loss)			28			(7	)		21
	Net current period other comprehensive income			64			2			66
	Balance, March 31, 2014		$	(1,211	)	$	16		$	(1,195	)
	The following table provides additional detail about accumulated other comprehensive income (loss) components which were reclassified to the condensed consolidated statement of operations during the three months ended March 31, 2014 and 2013 (in thousands):
			Three Months Ended March 31,
			2014			2013
	Details about Accumulated Other		Amount reclassified from Accumulated						Affected line item in the
	Comprehensive Income (Loss) Components		Other Comprehensive Income (Loss)						Condensed Consolidated
									Statement of Operations
	Pension liability adjustment
	Net periodic pension cost		$	(43	)	$	(98	)	Cost of sales
				15			33		Tax benefit
			$	(28	)	$	(65	)	Net of tax
	Deferred gain on cash flow derivatives
	Gain on cash flow derivatives		$	11		$	26		Net sales
				(4	)		(10	)	Tax expense
			$	7		$	16		Net of tax
	Total reclassifications for the period		$	(21	)	$	(49	)

Recent_Accounting_and_Reportin

Recent Accounting and Reporting Developments	3 Months Ended
	Mar. 31, 2014
Accounting Changes And Error Corrections [Abstract]	'
Recent Accounting and Reporting Developments	'
	12	Recent Accounting and Reporting Developments
	In April 2014, the FASB issued ASU 2014-08, which changes the criteria for when the disposal of a component of an entity may be presented as discontinued operations. The guidance requires that the disposal be considered strategic shift (such as the disposal of a major geographical area, a major line of business, a major equity method investment, or other major part of an entity) which will have a major effect on a reporting entity’s operating and financial results in order to be presented as discontinued operations. Disposals that do qualify for discontinued operations presentation will require expanded disclosures. The guidance is effective for disposals which occur during annual periods beginning on or after December 15, 2014.
	In July 2013, the FASB issued ASU 2013-11, which clarified guidance on the presentation of unrecognized tax benefits. The guidance requires that an unrecognized tax benefit, or portion of an unrecognized tax benefit, be presented in the financial statements as a reduction to a deferred tax asset for a net operating loss carryforward, a similar tax loss, or a tax credit carryforward when such items exist in the same taxing jurisdiction. This guidance is effective for interim and annual periods beginning after December 15, 2013. The Company adopted this guidance on January 1, 2014 as required.

Basis_of_Presentation_Policies

Basis of Presentation (Policies)	3 Months Ended
	Mar. 31, 2014
Accounting Policies [Abstract]	'
Consolidation Policy	'
	The condensed consolidated financial statements include the accounts of Northwest Pipe Company (the “Company”) and its subsidiaries in which the Company exercises control as of the financial statement date. Intercompany accounts and transactions have been eliminated.
Basis of Accounting	'
	The accompanying unaudited condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America. The financial information as of December 31, 2013 is derived from the audited consolidated financial statements presented in the Company’s Annual Report on Form 10-K for the year ended December 31, 2013 (the “2013 Form 10-K”). Certain information or footnote disclosures normally included in consolidated financial statements prepared in accordance with accounting principles generally accepted in the United States of America have been condensed or omitted, pursuant to the rules and regulations of the Securities and Exchange Commission (the “SEC”). In the opinion of management, the accompanying condensed consolidated financial statements include all adjustments necessary (which are of a normal and recurring nature) for the fair statement of the results of the interim periods presented. The condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and notes thereto together with management’s discussion and analysis of financial condition and results of operations contained in the Company’s 2013 Form 10-K.

Acquisitions_and_Disposals_Tab

Acquisitions and Disposals (Tables)	3 Months Ended
	Mar. 31, 2014
Business Combinations [Abstract]	'
Summary of Components of Balance Sheet Accounts Classified as Assets and Liabilities of Discontinued Operations	'
	The table below presents the components of the balance sheet accounts associated with the OCTG business as of December 31, 2013, in thousands. All assets and liabilities were transferred to the buyer as of March 30, 2014.
		December 31,
		2013
	Assets:
	Trade and other receivables, net	$	11,673
	Inventories		44,668
	Prepaid expenses and other		206
	Total current assets		56,547
	Property and equipment, net		11,509
	Total assets		68,056
	Liabilities:
	Current portion of capital lease obligations		1,289
	Accounts payable		3,013
	Accrued liabilities		1,466
	Deferred revenue		4,505
	Total current liabilities		10,273
	Capital lease obligations, less current portion		4,075
	Total liabilities	$	14,348
Summary of Operating Results for Company's Discontinued Operations	'
	The table below presents the operating results for the Company’s discontinued operations (in thousands). These operating results for the three months ended March 31, 2014 do not necessarily reflect what they would have been had the OCTG business not been classified as a discontinued operation.
		Three Months Ended March 31,
		2014			2013
	Net sales	$	22,225		$	33,261
	Cost of sales		24,393			34,976
	Gross loss		(2,167	)		(1,715	)
	Selling, general and administrative expense		396			353
	Operating loss		(2,563	)		(2,068	)
	Interest expense		99			92
	Loss on sale of discontinued operations		12,083			—
	Loss before income taxes		(14,745	)		(2,160	)
	Benefit from income taxes		(6,066	)		(690	)
	Net loss from discontinued operations	$	(8,679	)	$	(1,470	)

Inventories_Tables

Inventories (Tables)	3 Months Ended
	Mar. 31, 2014
Inventory Disclosure [Abstract]	'
Components of Inventories	'
	Inventories are stated at the lower of cost or market and consist of the following (in thousands):
		March 31,		December 31,
		2014		2013
	Short-term inventories:
	Raw materials	$	43,061	$	52,598
	Work-in-process		3,261		4,902
	Finished goods		14,364		49,351
	Supplies		2,288		3,541
			62,974		110,392
	Long-term inventories:
	Finished goods		1,208		1,249
	Total inventories	$	64,182	$	111,641

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2014
Fair Value Disclosures [Abstract]	'
Assets and Liabilities Measured at Fair Value on Recurring Basis	'
	The following table summarizes information regarding the Company’s financial assets and financial liabilities that are measured at fair value (in thousands):
	Description	Balance at			Level 1		Level 2			Level 3
		March 31,
		2014
	Financial Assets
	Non-qualified retirement savings plan assets	$	6,102		$	4,975	$	1,127		$	—
	Derivatives		107			—		107			—
	Total Assets	$	6,209		$	4,975	$	1,234		$	—
	Financial Liabilities
	Contingent consideration	$	(4,486	)	$	—	$	—		$	(4,486	)
	Derivatives		(68	)		—		(68	)		—
	Total Liabilities	$	(4,554	)	$	—	$	(68	)	$	(4,486	)
	Description	Balance at			Level 1		Level 2			Level 3
		December 31,
		2013
	Financial Assets
	Non-qualified retirement savings plan assets	$	6,000		$	4,944	$	1,056		$	—
	Derivatives		1			—		1			—
	Total Assets	$	6,001		$	4,944	$	1,057		$	—
	Financial Liabilities
	Contingent consideration	$	(4,425	)	$	—	$	—		$	(4,425	)
	Derivatives		(1	)		—		(1	)		—
	Total Liabilities	$	(4,426	)	$	—	$	(1	)	$	(4,425	)

Segment_Information_Tables

Segment Information (Tables)	3 Months Ended
	Mar. 31, 2014
Segment Reporting [Abstract]	'
Segment Information Report of Statements of Operations	'
	The operating results of the OCTG business have been classified as discontinued operations and are not included in the operating results presented below.
		Three months ended March 31,
		2014			2013
		(in thousands)
	Net sales:
	Water transmission	$	42,999		$	78,613
	Tubular products		39,648			28,722
	Total	$	82,647		$	107,335
	Gross profit:
	Water transmission	$	1,668		$	19,870
	Tubular products		2,646			3,049
	Total	$	4,314		$	22,919
	Operating income (loss):
	Water transmission	$	(299	)	$	18,033
	Tubular products		2,294			2,735
	Corporate		(3,121	)		(3,879	)
	Total	$	(1,126	)	$	16,889

Sharebased_Compensation_Tables

Share-based Compensation (Tables)	3 Months Ended
	Mar. 31, 2014
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]	'
Summary of Share-Based Compensation Expense	'
	The following summarizes share-based compensation expense recorded (in thousands):
		Three months ended March 31,
		2014			2013
	Cost of sales	$	11		$	128
	Selling, general and administrative expenses		343			398
	Total	$	354		$	526
Summary of Status of Company's Stock Options	'
	A summary of the status of the Company’s stock options as of March 31, 2014 and changes during the three months then ended is presented below:
		Options			Weighted		Weighted		Aggregate
		Outstanding			Average		Average		Intrinsic Value
					Exercise Price		Remaining
					per Share		Contractual
							Life
									(In thousands)
	Balance, January 1, 2014		40,000		$	25.44
	Options granted		—			—
	Options exercised or exchanged		—			—
	Options canceled		—			—
	Balance, March 31, 2014		40,000			25.44		4.4	$	429
	Exercisable, March 31, 2014		40,000			25.44		4.4	$	429
Summary of Status of Company's RSUs and PSAs	'
	A summary of the status of the Company’s RSUs and PSAs as of March 31, 2014 and changes during the three months then ended is presented below:
		Number of RSUs			Weighted Average
		and PSAs			Grant Date Fair Value
	Unvested RSUs and PSAs at January 1, 2014		257,087		$	30.69
	RSUs and PSAs granted		—			—
	RSUs and PSAs vested		(80,469	)		25.82
	RSUs and PSAs canceled		(21,625	)		31.47
	Unvested RSUs and PSAs at March 31, 2014		154,993			33.12

Earnings_per_Share_Tables

Earnings per Share (Tables)	3 Months Ended
	Mar. 31, 2014
Earnings Per Share [Abstract]	'
Earnings per Basic and Diluted Weighted Average Common Share Outstanding for Continuing and Discontinued Operations	'
	Earnings per basic and diluted weighted average common share outstanding for continuing and discontinued operations were calculated as follows for the three months ended March 31, 2014 and 2013 (in thousands, except per share data):
			Three Months Ended March 31,
			2014			2013
	Net income (loss) from continuing operations		$	(1,211	)	$	10,976
	Net loss from discontinued operations			(8,679	)		(1,470	)
	Net income (loss)		$	(9,890	)	$	9,506
	Basic weighted-average common shares outstanding			9,508			9,437
	Effect of potentially dilutive common shares(1)			—			47
	Diluted weighted-average common shares outstanding			9,508			9,484
	Earnings (loss) per basic common share
	Continuing operations			(0.13	)		1.16
	Discontinued operations			(0.91	)		(0.15	)
	Total		$	(1.04	)	$	1.01
	Earnings (loss) per diluted common share
	Continuing operations			(0.13	)		1.16
	Discontinued operations			(0.91	)		(0.16	)
	Total		$	(1.04	)	$	1
	Antidilutive shares not included in diluted common share calculation			—			10
	-1	Represents the effect of the assumed exercise of stock options and the vesting of restricted stock units and performance stock awards, based on the treasury stock method.

Accumulated_Other_Comprehensiv1

Accumulated Other Comprehensive Income (Loss) (Tables)	3 Months Ended
	Mar. 31, 2014
Equity [Abstract]	'
Schedule of Components of Accumulated Other Comprehensive Income (Loss)	'
	The following table summarizes changes in the components of accumulated other comprehensive income (loss) during the three months ended March 31, 2014 (in thousands). All amounts are net of tax:
		Defined Benefit			Gains (Losses) on			Total
		Pension Items			Cash Flow
					Hedges
	Balance, December 31, 2013	$	(1,275	)	$	14		$	(1,261	)
	Other comprehensive income before reclassifications		36			9			45
	Amounts reclassified from accumulated other comprehensive income (loss)		28			(7	)		21
	Net current period other comprehensive income		64			2			66
	Balance, March 31, 2014	$	(1,211	)	$	16		$	(1,195	)
Schedule of Reclassifications of Accumulated Other Comprehensive Income (Loss)	'
	The following table provides additional detail about accumulated other comprehensive income (loss) components which were reclassified to the condensed consolidated statement of operations during the three months ended March 31, 2014 and 2013 (in thousands):
		Three Months Ended March 31,
		2014			2013
	Details about Accumulated Other	Amount reclassified from Accumulated						Affected line item in the
	Comprehensive Income (Loss) Components	Other Comprehensive Income (Loss)						Condensed Consolidated
								Statement of Operations
	Pension liability adjustment
	Net periodic pension cost	$	(43	)	$	(98	)	Cost of sales
			15			33		Tax benefit
		$	(28	)	$	(65	)	Net of tax
	Deferred gain on cash flow derivatives
	Gain on cash flow derivatives	$	11		$	26		Net sales
			(4	)		(10	)	Tax expense
		$	7		$	16		Net of tax
	Total reclassifications for the period	$	(21	)	$	(49	)

Acquisitions_and_Disposals_Add

Acquisitions and Disposals - Additional Information (Detail) (USD $)	0 Months Ended	3 Months Ended
	Dec. 30, 2013	Mar. 31, 2014
Business Acquisition [Line Items]	'	'
Loss on sale of discontinued operations	'	12,083,000
Proceeds from sale of business	'	31,609,000
Permalok Corporation [Member]	'	'
Business Acquisition [Line Items]	'	'
Business acquisition date	'	30-Dec-13
Business acquisition, percentage	100.00%	'
Business acquisition (net of received), amount paid	15,700,000	'
Business acquisition, goodwill	5,300,000	'
Disposal of OCTG Business [Member]	'	'
Business Acquisition [Line Items]	'	'
Proceeds from sale of business	'	42,700,000
Loss on sale of discontinued operations	'	12,083,000
Proceeds held in escrow for indemnification obligations under the purchase agreement	'	4,300,000
Payment of capital lease obligations at closing date	'	5,000,000
Goodwill written off related to sale of business	'	4,400,000
Transaction costs	'	1,800,000
Proceeds from sale of business	'	31,600,000
Accrued Liabilities [Member] | Permalok Corporation [Member]	'	'
Business Acquisition [Line Items]	'	'
Business acquisition, contingent consideration recorded	'	1,400,000
Other Long-term Liabilities [Member] | Permalok Corporation [Member]	'	'
Business Acquisition [Line Items]	'	'
Business acquisition, contingent consideration recorded	'	3,100,000

Acquisitions_and_Disposals_Sum

Acquisitions and Disposals - Summary of Components of Balance Sheet Accounts Which were Sold (Detail) (USD $)	Dec. 31, 2013
In Millions, unless otherwise specified
Assets:	'
Trade and other receivables, net	$11,673
Inventories	44,668
Prepaid expenses and other	206
Total current assets	56,547
Property and equipment, net	11,509
Total assets	68,056
Liabilities:	'
Current portion of capital lease obligations	1,289
Accounts payable	3,013
Accrued liabilities	1,466
Deferred revenue	4,505
Total current liabilities	10,273
Capital lease obligations, less current portion	4,075
Total liabilities	$14,348

Acquisitions_and_Disposals_Sum1

Acquisitions and Disposals - Summary of Operating Results for Company's Discontinued Operations (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Business Combination Increase Decrease To Reflect Liabilities Acquired At Fair Value [Abstract]	'	'
Net sales	$22,225	$33,261
Cost of sales	24,393	34,976
Gross loss	-2,167	-1,715
Selling, general and administrative expense	396	353
Operating loss	-2,563	-2,068
Interest expense	99	92
Loss on sale of discontinued operations	12,083	'
Loss before income taxes	-14,745	-2,160
Benefit from income taxes	-6,066	-690
Net loss from discontinued operations	($8,679)	($1,470)

Inventories_Components_of_Inve

Inventories - Components of Inventories (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Short-term inventories:	'	'
Raw materials	$43,061	$52,598
Work-in-process	3,261	4,902
Finished goods	14,364	49,351
Supplies	2,288	3,541
Total short-term inventories	62,974	110,392
Long-term inventories:	'	'
Finished goods	1,208	1,249
Total inventories	$64,182	$111,641

Fair_Value_Measurements_Assets

Fair Value Measurements - Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) (Recurring [Member], USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Financial Assets	'	'
Non-qualified retirement savings plan assets	$6,102	$6,000
Derivatives	107	1
Total Assets	6,209	6,001
Financial Liabilities	'	'
Contingent consideration	-4,486	-4,425
Derivatives	-68	-1
Total Liabilities	-4,554	-4,426
Level 1 [Member]	'	'
Financial Assets	'	'
Non-qualified retirement savings plan assets	4,975	4,944
Derivatives	'	'
Total Assets	4,975	4,944
Financial Liabilities	'	'
Contingent consideration	'	'
Derivatives	'	'
Total Liabilities	'	'
Level 2 [Member]	'	'
Financial Assets	'	'
Non-qualified retirement savings plan assets	1,127	1,056
Derivatives	107	1
Total Assets	1,234	1,057
Financial Liabilities	'	'
Contingent consideration	'	'
Derivatives	-68	-1
Total Liabilities	-68	-1
Level 3 [Member]	'	'
Financial Assets	'	'
Non-qualified retirement savings plan assets	'	'
Derivatives	'	'
Total Assets	'	'
Financial Liabilities	'	'
Contingent consideration	-4,486	-4,425
Derivatives	'	'
Total Liabilities	($4,486)	($4,425)

Fair_Value_Measurements_Additi

Fair Value Measurements - Additional Information (Detail) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Fair Value Disclosures [Abstract]	'	'
Fair value discount rate	5.30%	'
Fair value of long-term debt	$3.50	$6.30
Carrying value of long-term debt	$3.60	$6.40

Derivative_Instruments_and_Hed1

Derivative Instruments and Hedging Activities - Additional Information (Detail)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014	Dec. 31, 2013	Dec. 31, 2013	Mar. 31, 2014	Mar. 31, 2014	Dec. 31, 2013	Dec. 31, 2013
	USD ($)	USD ($)	Not Designated As Hedging Instrument [Member]	Not Designated As Hedging Instrument [Member]	Not Designated As Hedging Instrument [Member]	Designated As Hedging Instrument [Member]	Designated As Hedging Instrument [Member]	Designated As Hedging Instrument [Member]	Designated As Hedging Instrument [Member]
			USD ($)	USD ($)	CAD	USD ($)	CAD	USD ($)	CAD
Derivatives, Fair Value [Line Items]	'	'	'	'	'	'	'	'	'
Notional amount of derivative contracts	'	'	$0	$0.10	0.1	$5.40	6	$3.80	4.1
Maturity period for Canadian forward contracts	'12 months	'	'	'	'	'	'	'	'
Gains (losses) from derivative contracts not designated as hedging instruments recognized in net sales	0.1	-0.1	'	'	'	'	'	'	'
Unrealized pretax gain on outstanding derivatives accumulated in other comprehensive loss expected to be reclassified to net sales within next 12 months	$0.10	'	'	'	'	'	'	'	'

Commitments_and_Contingencies_

Commitments and Contingencies - Additional Information (Detail) (USD $)	1 Months Ended			3 Months Ended
	Jun. 30, 2007	Mar. 31, 2014	Mar. 31, 2014	Mar. 31, 2014	Mar. 31, 2014
		Parties	Portland Harbor Natural Resources Trustee Council [Member]	Minimum [Member]	Maximum [Member]
Other Commitments [Line Items]	'	'	'	'	'
Company made payment to Lower Willamette Group as interim settlement	$175,000	'	'	'	'
Liability to pay	0	'	0	'	'
Estimated cost	'	'	'	169,000,000	1,760,000,000
Estimated years to implement	'	'	'	'2 years	'28 years
Amount anticipated to spent for further Source Control work	'	100,000	'	'	'
Number of potentially responsible parties	'	100	'	'	'
Total stand-by letters of credit	'	$3,100,000	'	'	'

Segment_Information_Additional

Segment Information - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2014
	Segment
Segment Reporting [Abstract]	'
Number of reportable segments	2

Segment_Information_Segment_In

Segment Information - Segment Information Report of Statements of Operations (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Segment Reporting Information [Line Items]	'	'
Net sales	$82,647	$107,335
Gross profit	4,314	22,919
Operating income (loss)	-1,126	16,889
Corporate [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Operating income (loss)	-3,121	-3,879
Water Transmission [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Net sales	42,999	78,613
Gross profit	1,668	19,870
Operating income (loss)	-299	18,033
Tubular Products [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Net sales	39,648	28,722
Gross profit	2,646	3,049
Operating income (loss)	$2,294	$2,735

ShareBased_Compensation_Plans_

Share-Based Compensation Plans - Additional Information (Detail) (USD $)	3 Months Ended
In Millions, except Share data, unless otherwise specified	Mar. 31, 2014
	OptionPlan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Number of inactive stock option plan	1
Number of active stock incentive plan	1
RSUs and PSAs at target level of performance included in unvested balance	129,000
Minimum performance awards issued multiplier	0.00%
Maximum performance awards issued multiplier	200.00%
Minimum [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Vesting period of market based PSAs	'2 years
Maximum [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Vesting period of market based PSAs	'3 years
Restricted Stock Units and Performance Stock Awards [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Unrecognized compensation expense	3.1
Expected weighted average period of compensation expense to be recognized	'1 year 7 months 6 days

ShareBased_Compensation_Summar

Share-Based Compensation - Summary of Share-Based Compensation Expense (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'
Share-based compensation expense	$354	$526
Cost of Sales [Member]	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'
Share-based compensation expense	11	128
Selling, General and Administrative Expenses [Member]	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'
Share-based compensation expense	$343	$398

ShareBased_Compensation_Summar1

Share-Based Compensation - Summary of Status of Company's Stock Options (Detail) (USD $)	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2014
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]	'
Options outstanding, beginning balance	40,000
Options outstanding, granted	'
Options outstanding, exercised or exchanged	'
Options outstanding, canceled	'
Options outstanding, ending balance	40,000
Exercisable, options outstanding	40,000
Options, weighted average exercise price, beginning balance	$25.44
Options granted, weighted average exercise price	'
Options exercised or exchanged, weighted average exercise price	'
Options canceled, weighted average exercise price	'
Options, weighted average exercise price, ending balance	$25.44
Exercisable, weighted average exercise price	$25.44
Outstanding, weighted average remaining contractual life	'4 years 4 months 24 days
Exercisable, weighted average remaining contractual life	'4 years 4 months 24 days
Outstanding, aggregate intrinsic value	$429
Exercisable, aggregate intrinsic value	$429

ShareBased_Compensation_Summar2

Share-Based Compensation - Summary of Status of Company's RSUs and PSAs (Detail) (Restricted Stock Units and Performance Stock Awards [Member], USD $)	3 Months Ended
	Mar. 31, 2014
Restricted Stock Units and Performance Stock Awards [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Unvested RSUs and PSAs, beginning balance	257,087
RSUs and PSAs granted	'
RSUs and PSAs vested	-80,469
RSUs and PSAs canceled	-21,625
Unvested RSUs and PSAs, ending balance	154,993
Unvested RSUs and PSAs, weighted average grant date fair value, beginning balance	$30.69
RSUs and PSAs granted, weighted average grant date fair value	'
RSUs and PSAs vested, weighted average grant date fair value	$25.82
RSUs and PSAs canceled, weighted average grant date fair value	$31.47
Unvested RSUs and PSAs, weighted average grant date fair value, ending balance	$33.12

Income_Taxes_Additional_Inform

Income Taxes - Additional Information (Detail) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Income Tax Disclosure [Abstract]	'	'	'
Unrecognized tax benefits	$2.90	'	$6.20
Expected change in unrecognized tax benefits	$2.40	'	'
Estimated effective tax rates	35.50%	31.70%	'

Earnings_per_Share_Earnings_pe

Earnings per Share - Earnings per Basic and Diluted Weighted Average Common Share Outstanding for Continuing and Discontinued Operations (Detail) (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Earnings Per Share [Abstract]	'	'
Net income (loss) from continuing operations	($1,211)	$10,976
Net loss from discontinued operations	-8,679	-1,470
Net income (loss)	($9,890)	$9,506
Basic weighted-average common shares outstanding	9,508	9,437
Effect of potentially dilutive common shares	'	47
Diluted weighted-average common shares outstanding	9,508	9,484
Earnings (loss) per basic common share	'	'
Continuing operations	($0.13)	$1.16
Discontinued operations	($0.91)	($0.15)
Total	($1.04)	$1.01
Earnings (loss) per diluted common share	'	'
Continuing operations	($0.13)	$1.16
Discontinued operations	($0.91)	($0.16)
Total	($1.04)	$1
Antidilutive shares not included in diluted common share calculation	'	10

Accumulated_Other_Comprehensiv2

Accumulated Other Comprehensive Income (Loss) - Schedule of Components of Accumulated Other Comprehensive Income (Loss) (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'
Accumulated other comprehensive income (loss), Beginning Balance	($1,261)	'
Other comprehensive income before reclassifications	45	'
Amounts reclassified from accumulated other comprehensive income (loss)	21	'
Other comprehensive income	66	176
Accumulated other comprehensive income (loss), Ending Balance	-1,195	'
Pension Liability Adjustment [Member]	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'
Accumulated other comprehensive income (loss), Beginning Balance	-1,275	'
Other comprehensive income before reclassifications	36	'
Amounts reclassified from accumulated other comprehensive income (loss)	28	'
Other comprehensive income	64	'
Accumulated other comprehensive income (loss), Ending Balance	-1,211	'
Deferred Gain on Cash Flow Derivatives [Member]	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'
Accumulated other comprehensive income (loss), Beginning Balance	14	'
Other comprehensive income before reclassifications	9	'
Amounts reclassified from accumulated other comprehensive income (loss)	-7	'
Other comprehensive income	2	'
Accumulated other comprehensive income (loss), Ending Balance	$16	'

Accumulated_Other_Comprehensiv3

Accumulated Other Comprehensive Income (Loss) - Schedule of Reclassifications of Accumulated Other Comprehensive Income (Loss) (Detail) (Amount Reclassified from Accumulated Other Comprehensive Income (Loss) [Member], USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]	'	'
Reclassifications for the period recognized in net income (loss)	($21)	($49)
Pension Liability Adjustment [Member]	'	'
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]	'	'
Cost of Sales	-43	-98
Tax (expense) benefit	15	33
Reclassifications for the period recognized in net income (loss)	-28	-65
Deferred Gain on Cash Flow Derivatives [Member]	'	'
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]	'	'
Net Sales	11	26
Tax (expense) benefit	-4	-10
Reclassifications for the period recognized in net income (loss)	$7	$16