Nature of Operations and Basis of Presentation	9 Months Ended
Sep. 30, 2017
Accounting Policies [Abstract]
Nature of Operations and Basis of Presentation	Nature of Operations and Basis of Presentation GENERAL Clearwater Paper manufactures quality consumer tissue, away-from-home tissue, parent roll tissue, bleached paperboard and pulp at manufacturing facilities across the nation. The company is a premier supplier of private label tissue to major retailers and wholesale distributors, including grocery, drug, mass merchants and discount stores. In addition, the company produces bleached paperboard used by quality-conscious printers and packaging converters, and offers services that include custom sheeting, slitting and cutting. Clearwater Paper's employees build shareholder value by developing strong customer relationships through quality and service. On December 16, 2016, we acquired Manchester Industries, an independently-owned paperboard sales, sheeting and distribution supplier to the packaging and commercial print industries, for total consideration of $71.7 million. The addition of Manchester Industries' customers to our paperboard business extends our reach and service platform to small and mid-sized folding carton plants, by offering a range of converting services that include custom sheeting, slitting, and cutting. These converting operations include five strategically located facilities in Virginia, Pennsylvania, Indiana, Texas, and Michigan. Goodwill was recorded in the acquisition of Manchester Industries based on the preliminary purchase price allocation. We are continuing to collect information to determine the fair values included in the purchase price in association with the final tax basis of acquired intangibles and fixed assets used in the determination of deferred tax liabilities at the acquisition date, which could affect our goodwill allocation for this transaction. On March 31, 2017, we closed our Oklahoma City, Oklahoma converting facility. Notwithstanding the closure, we remain subject to the terms of a long-term master lease applicable to the facility. In October 2017, we transferred to a third party substantially all of the remaining fixed assets and supplies inventory located at this facility and subleased the facility to the third party for the remaining term of the master lease for the facility. In connection with the transfer of fixed assets, we recorded a loss of $4.3 million in the third quarter of 2017 related primarily to the writedown of the transferred assets to their held for sale value. This loss is included in “Selling, general and administrative expenses” in our Consolidated Statement of Operations. We expect to record a loss of approximately $3 million in the fourth quarter of 2017 related to the execution of the sublease agreement. The sublease agreement is expected to substantially reduce our cash requirements under the master lease over the term of the sublease. Additionally, we have incurred $0.8 million and $6.8 million of closure-related costs associated with the Oklahoma City facility for the three and nine months ended September 30, 2017, respectively, which are included in "Cost of goods sold" in our Consolidated Statement of Operations. FINANCIAL STATEMENT PREPARATION AND PRESENTATION The accompanying Consolidated Balance Sheets at September 30, 2017 and December 31, 2016, the related Consolidated Statements of Operations and Comprehensive Income for the three and nine months ended September 30, 2017 and 2016, and the Consolidated Statements of Cash Flows for the nine months ended September 30, 2017 and 2016, have been prepared in conformity with accounting principles generally accepted in the United States of America, or GAAP. We believe that all adjustments necessary for a fair statement of the results of the interim periods presented have been included. The results of operations for any interim period are not necessarily indicative of the results of operations to be expected for the full year. This Quarterly Report on Form 10-Q should be read in conjunction with our Annual Report on Form 10-K for the year ended December 31, 2016, as filed with the Securities and Exchange Commission, or SEC, on February 22, 2017. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES SIGNIFICANT ESTIMATES The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of net sales and expenses during the reporting periods. Significant areas that may require the use of estimates and measurement of uncertainty include determination of net realizable value for deferred tax assets, uncertain tax positions, assessment of impairment of long-lived assets, goodwill and intangibles, assessment of environmental matters, equity-based compensation and pension and postretirement obligation assumptions. Actual results could differ from those estimates and assumptions. CASH AND CASH EQUIVALENTS We consider all highly liquid instruments with maturities of three months or less to be cash equivalents. TRADE ACCOUNTS RECEIVABLE Trade accounts receivable are stated at the amount we expect to collect. Trade accounts receivable do not bear interest. The allowance for doubtful accounts is our best estimate of the losses we expect will result from the inability of our customers to make required payments. We generally determine the allowance based on a combination of actual historical write-off experience and an analysis of specific customer accounts. As of September 30, 2017 and December 31, 2016, we had allowances for doubtful accounts of $1.3 million and $1.5 million, respectively. PROPERTY, PLANT AND EQUIPMENT Property, plant and equipment are stated at cost, including any interest costs capitalized, less accumulated depreciation. Depreciation of buildings, equipment and other depreciable assets is determined using the straight-line method. Assets we acquire through business combinations have estimated lives that are typically shorter than the assets we construct or buy new. Accumulated depreciation totaled $1,617.5 million and $1,582.0 million at September 30, 2017 and December 31, 2016, respectively. For the nine months ended September 30, 2017, we capitalized $3.0 million of interest expense associated with the construction of a continuous pulp digester at our Lewiston, Idaho pulp and paperboard facility and $0.5 million associated with the construction of a paper machine at our Shelby, North Carolina consumer products facility. For the nine months ended September 30, 2016, we capitalized $1.6 million of interest expense associated with the continuous pulp digester project. In June 2017, we received land with a fair market value of $4.2 million from the City of Shelby, North Carolina and Cleveland County. We must fulfill certain obligations within five years or pay the value of the land or return the title to the land. This balance is included in "Property, plant, and equipment, net," with an associated amount in "Other long-term obligations" on our Consolidated Balance Sheet as of September 30, 2017. Consistent with authoritative guidance, we assess the carrying amount of long-lived assets with definite lives that are held-for-use and evaluate them for recoverability whenever events or changes in circumstances indicate that we may be unable to recover the carrying amount of the assets. STOCKHOLDERS’ EQUITY On December 15, 2015, we announced that our Board of Directors had approved a stock repurchase program authorizing the repurchase of up to $100 million of our common stock. The repurchase program authorizes purchases of our common stock from time to time through open market purchases, negotiated transactions or other means, including accelerated stock repurchases and 10b5-1 trading plans in accordance with applicable securities laws and other restrictions. We have no obligation to repurchase stock under this program and may suspend or terminate the program at any time. In total, we have repurchased 1,440,696 shares of our outstanding common stock as of September 30, 2017, pursuant to this repurchase program, of which 84,750 shares were repurchased during the first quarter of 2017 at an average price of $57.53 per share. We did not repurchase shares during the second or third quarters of 2017. As of September 30, 2017, we had up to $29.8 million of authorization remaining pursuant to this stock repurchase program. During the third quarter of 2017, we retired 7,821,005 treasury shares. The impact of this retirement was reflected within the stockholders' equity line items on our Consolidated Balance Sheet. DERIVATIVES We had no activity during the three and nine months ended September 30, 2017 and 2016 that required hedge or derivative accounting treatment. However, to help mitigate our exposure to market risk for changes in utility commodity pricing, we use firm price contracts to supply a portion of the natural gas requirements for our manufacturing facilities. As of September 30, 2017, these contracts covered approximately 30% of our expected average monthly natural gas requirements for the remainder of 2017, and a lesser amount for 2018. Historically, these contracts have qualified for treatment as “normal purchases or normal sales” under authoritative guidance and thus required no mark-to-market adjustment.

Nature of Operations and Basis of Presentation

GENERAL

Clearwater Paper manufactures quality consumer tissue, away-from-home tissue, parent roll tissue, bleached paperboard and pulp at manufacturing facilities across the nation. The company is a premier supplier of private label tissue to major retailers and wholesale distributors, including grocery, drug, mass merchants and discount stores. In addition, the company produces bleached paperboard used by quality-conscious printers and packaging converters, and offers services that include custom sheeting, slitting and cutting. Clearwater Paper's employees build shareholder value by developing strong customer relationships through quality and service.

On December 16, 2016, we acquired Manchester Industries, an independently-owned paperboard sales, sheeting and distribution supplier to the packaging and commercial print industries, for total consideration of $71.7 million. The addition of Manchester Industries' customers to our paperboard business extends our reach and service platform to small and mid-sized folding carton plants, by offering a range of converting services that include custom sheeting, slitting, and cutting. These converting operations include five strategically located facilities in Virginia, Pennsylvania, Indiana, Texas, and Michigan. Goodwill was recorded in the acquisition of Manchester Industries based on the preliminary purchase price allocation. We are continuing to collect information to determine the fair values included in the purchase price in association with the final tax basis of acquired intangibles and fixed assets used in the determination of deferred tax liabilities at the acquisition date, which could affect our goodwill allocation for this transaction.

On March 31, 2017, we closed our Oklahoma City, Oklahoma converting facility. Notwithstanding the closure, we remain subject to the terms of a long-term master lease applicable to the facility. In October 2017, we transferred to a third party substantially all of the remaining fixed assets and supplies inventory located at this facility and subleased the facility to the third party for the remaining term of the master lease for the facility. In connection with the transfer of fixed assets, we recorded a loss of $4.3 million in the third quarter of 2017 related primarily to the writedown of the transferred assets to their held for sale value. This loss is included in “Selling, general and administrative expenses” in our Consolidated Statement of Operations. We expect to record a loss of approximately $3 million in the fourth quarter of 2017 related to the execution of the sublease agreement. The sublease agreement is expected to substantially reduce our cash requirements under the master lease over the term of the sublease.

Additionally, we have incurred $0.8 million and $6.8 million of closure-related costs associated with the Oklahoma City facility for the three and nine months ended September 30, 2017, respectively, which are included in "Cost of goods sold" in our Consolidated Statement of Operations.

FINANCIAL STATEMENT PREPARATION AND PRESENTATION

The accompanying Consolidated Balance Sheets at September 30, 2017 and December 31, 2016, the related Consolidated Statements of Operations and Comprehensive Income for the three and nine months ended September 30, 2017 and 2016, and the Consolidated Statements of Cash Flows for the nine months ended September 30, 2017 and 2016, have been prepared in conformity with accounting principles generally accepted in the United States of America, or GAAP. We believe that all adjustments necessary for a fair statement of the results of the interim periods presented have been included. The results of operations for any interim period are not necessarily indicative of the results of operations to be expected for the full year.

This Quarterly Report on Form 10-Q should be read in conjunction with our Annual Report on Form 10-K for the year ended December 31, 2016, as filed with the Securities and Exchange Commission, or SEC, on February 22, 2017.

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

SIGNIFICANT ESTIMATES

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of net sales and expenses during the reporting periods. Significant areas that may require the use of estimates and measurement of uncertainty include determination of net realizable value for deferred tax assets, uncertain tax positions, assessment of impairment of long-lived assets, goodwill and intangibles, assessment of environmental matters, equity-based compensation and pension and postretirement obligation assumptions. Actual results could differ from those estimates and assumptions.

CASH AND CASH EQUIVALENTS

We consider all highly liquid instruments with maturities of three months or less to be cash equivalents.

TRADE ACCOUNTS RECEIVABLE

Trade accounts receivable are stated at the amount we expect to collect. Trade accounts receivable do not bear interest. The allowance for doubtful accounts is our best estimate of the losses we expect will result from the inability of our customers to make required payments. We generally determine the allowance based on a combination of actual historical write-off experience and an analysis of specific customer accounts. As of September 30, 2017 and December 31, 2016, we had allowances for doubtful accounts of $1.3 million and $1.5 million, respectively.

PROPERTY, PLANT AND EQUIPMENT

Property, plant and equipment are stated at cost, including any interest costs capitalized, less accumulated depreciation. Depreciation of buildings, equipment and other depreciable assets is determined using the straight-line method. Assets we acquire through business combinations have estimated lives that are typically shorter than the assets we construct or buy new. Accumulated depreciation totaled $1,617.5 million and $1,582.0 million at September 30, 2017 and December 31, 2016, respectively.

For the nine months ended September 30, 2017, we capitalized $3.0 million of interest expense associated with the construction of a continuous pulp digester at our Lewiston, Idaho pulp and paperboard facility and $0.5 million associated with the construction of a paper machine at our Shelby, North Carolina consumer products facility. For the nine months ended September 30, 2016, we capitalized $1.6 million of interest expense associated with the continuous pulp digester project. In June 2017, we received land with a fair market value of $4.2 million from the City of Shelby, North Carolina and Cleveland County. We must fulfill certain obligations within five years or pay the value of the land or return the title to the land. This balance is included in "Property, plant, and equipment, net," with an associated amount in "Other long-term obligations" on our Consolidated Balance Sheet as of September 30, 2017.

Consistent with authoritative guidance, we assess the carrying amount of long-lived assets with definite lives that are held-for-use and evaluate them for recoverability whenever events or changes in circumstances indicate that we may be unable to recover the carrying amount of the assets.

STOCKHOLDERS’ EQUITY

On December 15, 2015, we announced that our Board of Directors had approved a stock repurchase program authorizing the repurchase of up to $100 million of our common stock. The repurchase program authorizes purchases of our common stock from time to time through open market purchases, negotiated transactions or other means, including accelerated stock repurchases and 10b5-1 trading plans in accordance with applicable securities laws and other restrictions. We have no obligation to repurchase stock under this program and may suspend or terminate the program at any time. In total, we have repurchased 1,440,696 shares of our outstanding common stock as of September 30, 2017, pursuant to this repurchase program, of which 84,750 shares were repurchased during the first quarter of 2017 at an average price of $57.53 per share. We did not repurchase shares during the second or third quarters of 2017. As of September 30, 2017, we had up to $29.8 million of authorization remaining pursuant to this stock repurchase program.

During the third quarter of 2017, we retired 7,821,005 treasury shares. The impact of this retirement was reflected within the stockholders' equity line items on our Consolidated Balance Sheet.

DERIVATIVES

We had no activity during the three and nine months ended September 30, 2017 and 2016 that required hedge or derivative accounting treatment. However, to help mitigate our exposure to market risk for changes in utility commodity pricing, we use firm price contracts to supply a portion of the natural gas requirements for our manufacturing facilities. As of September 30, 2017, these contracts covered approximately 30% of our expected average monthly natural gas requirements for the remainder of 2017, and a lesser amount for 2018. Historically, these contracts have qualified for treatment as “normal purchases or normal sales” under authoritative guidance and thus required no mark-to-market adjustment.