Packaging Corporation of America (PKG) 10-K 28 Feb 18 2017 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2017	Feb. 23, 2018	Jun. 30, 2017
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	FY
Trading Symbol	PKG
Entity Registrant Name	PACKAGING CORP OF AMERICA
Entity Central Index Key	75,677
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		94,349,822
Entity Public Float			$ 10,380,184,252

Consolidated Statements of Inco

Consolidated Statements of Income and Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017		Dec. 31, 2016	Dec. 31, 2015
Income Statement [Abstract]
Net sales	$ 6,444.9		$ 5,779	$ 5,741.7
Cost of sales	(4,972.7)		(4,503.3)	(4,533.7)
Gross profit	1,472.2		1,275.7	1,208
Selling and administrative expenses	(522.6)		(471.1)	(451.3)
Other expense, net	(18.4)		(24.3)	(6.7)
Income from operations	931.2		780.3	750
Interest expense, net	(102.6)	[1]	(91.8)	(85.5)
Income before taxes	828.6		688.5	664.5
Provision for income taxes	(160)		(238.9)	(227.7)
Net income	$ 668.6		$ 449.6	$ 436.8
Net income per common share:
Basic	$ 7.09		$ 4.76	$ 4.47
Diluted	7.07		4.75	4.47
Dividends declared per common share	$ 2.52		$ 2.36	$ 2.20
Statements of Comprehensive Income:
Net income	$ 668.6		$ 449.6	$ 436.8
Foreign currency translation adjustment	(0.2)		0	2.7
Reclassification adjustments to cash flow hedges included in net income, net of tax of $2.2 million, $2.2 million, and $2.2 million for 2017, 2016, and 2015, respectively	3.5		3.5	3.5
Amortization of pension and postretirement plans actuarial loss and prior service cost, net of tax of $4.9 million, $4.2 million, and $5.6 million for 2017, 2016, and 2015, respectively	8.2		6.7	8.8
Changes in unfunded employee benefit obligations, net of tax of $18.0 million, $15.7 million, and ($8.9) million for 2017, 2016, and 2015, respectively	(28.8)		(24.9)	14
Other comprehensive income (loss)	(17.3)		(14.7)	29
Comprehensive income	$ 651.3		$ 434.9	$ 465.8
[1]	Includes $1.8 million of expense related to the write-off of deferred debt issuance costs in connection with the December 2017 debt refinancing.

Consolidated Statements of Inc3

Consolidated Statements of Income and Comprehensive Income (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Statement [Abstract]
Reclassification adjustments to cash flow hedges included in net income, tax	$ 2.2	$ 2.2	$ 2.2
Amortization of pension and postretirement plans actuarial loss and prior service cost, tax	4.9	4.2	5.6
Changes in unfunded employee benefit obligations, tax	$ 18	$ 15.7	$ (8.9)

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 216.9	$ 239.3
Accounts receivable, net of allowance for doubtful accounts and customer deductions of $12.6 million and $10.1 million as of December 31, 2017 and 2016, respectively	830.7	689.2
Inventories	762.5	723.6
Prepaid expenses and other current assets	35.5	30.3
Federal and state income taxes receivable	69.5	13.9
Total current assets	1,915.1	1,696.3
Property, plant and equipment, net	2,924.9	2,895.7
Goodwill	883.2	737.9
Other intangible assets, net	410	367.1
Other long-term assets	64.3	80
Total assets	6,197.5	5,777
Current liabilities:
Current maturities of long-term debt	150	25.8
Capital lease obligations	1.3	1.3
Accounts payable	402.9	323.8
Dividends payable	60.5	59.9
Accrued liabilities	203.2	201.2
Accrued interest	14.8	13.4
Total current liabilities	832.7	625.4
Long-term liabilities:
Long-term debt	2,480.4	2,620
Capital lease obligations	19	20.3
Deferred income taxes	239.5	334.7
Compensation and benefits	372.5	357.2
Other long-term liabilities	70.8	59.6
Total long-term liabilities	3,182.2	3,391.8
Commitments and contingent liabilities
Stockholders' equity:
Common stock, par value $0.01 per share, 300.0 million shares authorized, 94.3 million and 94.2 million shares issued as of December 31, 2017 and 2016, respectively	0.9	0.9
Additional paid in capital	471.2	451.4
Retained earnings	1,867.4	1,447.1
Accumulated other comprehensive loss	(156.9)	(139.6)
Total stockholders' equity	2,182.6	1,759.8
Total liabilities and stockholders' equity	$ 6,197.5	$ 5,777

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Statement Of Financial Position [Abstract]
Allowance for doubtful accounts and customer deductions	$ 12.6	$ 10.1
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	300,000,000	300,000,000
Common stock, shares issued	94,300,000	94,200,000

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash Flows from Operating Activities:
Net income		$ 668.6	$ 449.6	$ 436.8
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, depletion, and amortization of intangibles		391.4	358	356.5
Amortization of deferred financing costs		10	7.8	7.8
Share-based compensation expense		20.6	19.7	18.2
Deferred income tax (benefit) provision		(84.5)	(4)	1.7
Net loss on impairment of assets		13.5
Pension and post retirement benefits expense, net of contributions		(20.4)	(30.5)	31.2
Other, net		3	1.4	(19.8)
(Increase) decrease in assets —
Accounts receivable		(115.1)	(3.6)	9.5
Inventories		(21)	(25.7)	(11.9)
Prepaid expenses and other current assets		(5.2)		4.1
Increase (decrease) in liabilities —
Accounts payable		41	16.6	(37.3)
Accrued liabilities		8.4	(3.2)	(15.5)
Federal and state income tax payable / receivable		(54.2)	20.8	(12.7)
Net cash provided by operating activities		856.1	806.9	768.6
Cash Flows from Investing Activities:
Additions to property, plant, and equipment	[1]	(343)	(274.3)	(314.5)
Proceeds from sale of a business				23
Acquisitions of businesses, net of cash acquired		(273.8)	(485.4)
Additions to other long term assets		(7.8)	(10.4)	(12.3)
Proceeds from asset disposals		16.6	0.5	1.5
Other, net		(1.1)		4.2
Net cash used for investing activities		(609.1)	(769.6)	(298.1)
Cash Flows from Financing Activities:
Proceeds from issuance of debt		997.8	385
Repayments of debt and capital lease obligations		(1,011.9)	(37.5)	(47.6)
Financing costs paid		(6.8)	(2)
Common stock dividends paid		(237.6)	(216.1)	(200.8)
Repurchases of common stock			(100.3)	(154.7)
Shares withheld to cover employee restricted stock taxes		(10.8)	(11.2)	(8.7)
Other, net		(0.1)	(0.1)	0.6
Net cash provided by (used for) financing activities		(269.4)	17.8	(411.2)
Net (decrease) increase in cash and cash equivalents		(22.4)	55.1	59.3
Cash and cash equivalents, beginning of year		239.3	184.2	124.9
Cash and cash equivalents, end of year		$ 216.9	$ 239.3	$ 184.2
[1]	Includes “Additions to property, plant, and equipment” and excludes cash used for “Acquisitions of businesses, net of cash acquired” as reported on our Consolidated Statements of Cash Flows.

Consolidated Statements of Chan

Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Millions	Total	Common Stock	Additional Paid in Capital	Retained Earnings	Accumulated Other Comprehensive Loss
Beginning Balance at Dec. 31, 2014	$ 1,521.4	$ 1	$ 432.1	$ 1,242.2	$ (153.9)
Beginning Balance (in shares) at Dec. 31, 2014		98,368,000
Common stock repurchases and retirements	$ (154.7)	$ 0	(15.6)	(139.1)	0
Common stock repurchases and retirements (in shares)	(2,326,493)	(2,326,000)
Common stock withheld and retired to cover taxes on vested stock awards	$ (8.7)	$ 0	(0.8)	(7.9)	0
Common stock withheld and retired to cover taxes on vested stock awards (in shares)		(131,000)
Common stock dividends declared	(214.7)	$ 0	0	(214.7)	0
Restricted stock/performance unit grants and cancellations	6	$ 0	6	0	0
Restricted stock/performance unit grants and cancellations (in shares)		218,000
Share-based compensation expense	18.2	$ 0	18.2	0	0
Comprehensive income	465.8	0	0	436.8	29
Ending Balance at Dec. 31, 2015	1,633.3	$ 1	439.9	1,317.3	(124.9)
Ending Balance (in shares) at Dec. 31, 2015		96,129,000
Common stock repurchases and retirements	$ (100.3)	$ (0.1)	(13.1)	(87.1)	0
Common stock repurchases and retirements (in shares)	(1,987,187)	(1,987,000)
Common stock withheld and retired to cover taxes on vested stock awards	$ (11.2)	$ 0	(1.1)	(10.1)	0
Common stock withheld and retired to cover taxes on vested stock awards (in shares)		(172,000)
Common stock dividends declared	(222.6)	$ 0	0	(222.6)	0
Restricted stock/performance unit grants and cancellations	5.7	$ 0	5.7	0	0
Restricted stock/performance unit grants and cancellations (in shares)		243,000
Share-based compensation expense	19.7	$ 0	19.7	0	0
Other	0.3	0	0.3	0	0
Comprehensive income	434.9	0	0	449.6	(14.7)
Ending Balance at Dec. 31, 2016	1,759.8	$ 0.9	451.4	1,447.1	(139.6)
Ending Balance (in shares) at Dec. 31, 2016		94,213,000
Common stock withheld and retired to cover taxes on vested stock awards	(10.8)	$ 0	(0.7)	(10.1)	0
Common stock withheld and retired to cover taxes on vested stock awards (in shares)		(98,000)
Common stock dividends declared	(238.2)	$ 0	0	(238.2)	0
Share-based compensation expense	20.6	$ 0	20.6	0	0
Share-based compensation (in shares)		235,000
Other	(0.1)	$ 0	(0.1)	0	0
Comprehensive income	651.3	0	0	668.6	(17.3)
Ending Balance at Dec. 31, 2017	$ 2,182.6	$ 0.9	$ 471.2	$ 1,867.4	$ (156.9)
Ending Balance (in shares) at Dec. 31, 2017		94,350,000

Nature of Operations and Basis

Nature of Operations and Basis of Presentation	12 Months Ended
	Dec. 31, 2017
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Nature of Operations and Basis of Presentation	1. Nature of Operations and Basis of Presentation Packaging Corporation of America (“we,” “us,” “our,” “PCA,” or the “Company”) was incorporated on January 25, 1999. In April 1999, PCA acquired the containerboard and corrugated packaging products business of Pactiv Corporation (Pactiv), formerly known as Tenneco Packaging, Inc., a wholly owned subsidiary of Tenneco Inc. In October 2013, PCA acquired Boise Inc. (Boise). After the acquisition of Boise, we became a large diverse manufacturer of both packaging and paper products. We are headquartered in Lake Forest, Illinois and we operate primarily in the United States. We have approximately 14,600 employees. We report our businesses in three reportable segments: Packaging, Paper, and Corporate and Other. Our Packaging segment produces a wide variety of corrugated packaging products. The Paper segment manufactures and sells a range of papers, including communication-based papers, and pressure sensitive papers. During the third quarter of 2017, the Company announced that it will discontinue the production of uncoated free sheet and coated one-side grades at the Wallula, Washington mill in the second quarter of 2018 to begin the conversion of the No.3 machine to a 400,000 ton-per-year virgin kraft linerboard machine. Corporate and other includes support staff services and related assets and liabilities, transportation assets, and activity related to other ancillary support operations. For more information about our segments, see Note 17, Segment Information. The consolidated financial statements include the accounts of PCA and its majority-owned subsidiaries after elimination of intercompany balances and transactions.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions about future events. These estimates and the underlying assumptions affect the amounts of assets and liabilities reported, disclosures about contingent assets and liabilities, and reported amounts of revenues and expenses. These estimates and assumptions are based on management's best estimates and judgment. Management evaluates its estimates and assumptions on an ongoing basis using historical experience and other factors, including the current economic environment. We adjust such estimates and assumptions when facts and circumstances dictate. As future events and their effects cannot be determined with precision, actual results could differ significantly from these estimates. Changes in these estimates will be reflected in the consolidated financial statements in future periods. Revenue Recognition We recognize revenue when the following criteria are met: persuasive evidence of an agreement exists, the customer takes title and assumes risks and rewards of ownership or services have been rendered, our price to the buyer is fixed or determinable, and collectability is reasonably assured. The timing of revenue recognition is dependent on transfer of title, which is normally either on exit from our plants (i.e., shipping point) or on arrival at customer’s location (i.e., destination point). Shipping and handling billings to a customer are included in net sales. Shipping and handling costs, such as freight to our customers' destinations, are included in cost of sales. We present taxes collected from customers and remitted to governmental authorities on a net basis in our Consolidated Statements of Income. Planned Major Maintenance Costs The Company accounts for its planned major maintenance activities in accordance with ASC 360, Property, Plant, and Equipment Share-Based Compensation We recognize compensation expense for awards granted under the PCA long-term equity incentive plans based on the fair value on the grant date. We recognize the cost of the equity awards expected to vest over the period the awards vest. See Note 12, Share-Based Compensation, for more information. Research and Development Research and development costs are expensed as incurred. The amount charged to expense was $12.8 million, $13.3 million, and $13.1 million for the years ended December 31, 2017, 2016, and 2015, respectively. Cash and Cash Equivalents Cash and cash equivalents include all cash balances and highly liquid investments with a stated maturity of three months or less. Cash equivalents are stated at cost, which approximates market. Cash and cash equivalents totaled $216.9 million and $239.3 million at December 31, 2017 and 2016, respectively, which included cash equivalents of $160.2 million Trade Accounts Receivable, Allowance for Doubtful Accounts, and Customer Deductions Trade accounts receivable are stated at the amount we expect to collect. The collectability of our accounts receivable is based upon a combination of factors. In circumstances where a specific customer is unable to meet its financial obligations to PCA (e.g., bankruptcy filings, substantial downgrading of credit sources), a specific reserve for bad debts is recorded against amounts due to the Company to reduce the net recorded receivable to the amount the Company reasonably believes will be collected. For all other customers, reserves for bad debts are recognized based on historical collection experience. If collection experience deteriorates (i.e., higher than expected defaults or an unexpected material adverse change in a major customer’s ability to meet its financial obligations to the Company), the estimate of the recoverability of amounts due could be reduced by a material amount. We periodically review our allowance for doubtful accounts and adjustments to the valuation allowance are recorded as income or expense. Trade accounts receivable balances that remain outstanding after we have used reasonable collection efforts are written off through a charge to the valuation allowance and a credit to accounts receivable. At December 31, 2017 and 2016, the allowance for doubtful accounts was $4.2 million and $3.8 million, respectively. The customer deductions reserve represents the estimated amount required for customer returns, allowances, and earned discounts. Based on the Company’s experience, customer returns, allowances, and earned discounts have averaged approximately 1% of gross selling price. Accordingly, PCA reserves 1% of its open customer accounts receivable balance for these items. The reserves for customer deductions of $8.4 million Derivative Instruments and Hedging Activities The Company records its derivatives, if any, in accordance with ASC 815, Derivatives and Hedging Fair Value Measurements PCA measures the fair value of its financial instruments in accordance with ASC 820, Fair Value Measurements and Disclosures Level 1 — Valuations based on quoted prices for identical assets and liabilities in active markets. Level 2 — Valuations based on observable inputs other than quoted prices included in Level 1, such as quoted prices for similar assets and liabilities in active markets, quoted prices for identical or similar assets and liabilities in markets that are not active, or other inputs that are observable or can be corroborated by observable market data. Level 3 — Valuations based on unobservable inputs in which there is little or no market data, which require the reporting entity to develop its own assumptions. Financial instruments measured at fair value on a recurring basis include the fair value of our pension and postretirement benefit assets and liabilities. See Note 10, Employee Benefit Plans and Other Postretirement Benefits for more information. Other assets and liabilities measured and recognized at fair value on a nonrecurring basis include assets acquired and liabilities assumed in acquisitions and our asset retirement obligations. Given the nature of these assets and liabilities, evaluating their fair value from the perspective of a market participant is inherently complex. Assumptions and estimates about future values can be affected by a variety of internal and external factors. Changes in these factors may require us to revise our estimates and could require us to retroactively adjust provisional amounts that we recorded for the fair values of assets acquired and liabilities assumed in connection with business combinations. These adjustments could have a material effect on our financial condition and results of operations. See Note 3, Acquisitions and Dispositions, and Note 11, Asset Retirement Obligations, for more information. Inventory Valuation We value our raw materials, work in process, and finished goods inventories using lower of cost, as determined by the average cost method, or market. Supplies and materials are valued at the first-in, first-out (FIFO) or average cost methods. The components of inventories were as follows (dollars in millions): December 31 2017 2016 Raw materials $ 279.8 $ 271.9 Work in process 12.6 12.9 Finished goods 217.0 206.5 Supplies and materials 253.1 232.3 Inventories $ 762.5 $ 723.6 Property, Plant, and Equipment Property, plant, and equipment are recorded at cost. Cost includes expenditures for major improvements and replacements and the amount of interest cost associated with significant capital additions. Repairs and maintenance costs are expensed as incurred . Property, plant, and equipment consisted of the following (dollars in millions): December 31 2017 2016 Land and land improvements $ 156.0 $ 149.7 Buildings 729.8 717.1 Machinery and equipment 5,162.5 4,951.4 Construction in progress 194.5 125.4 Other 68.4 66.7 Property, plant and equipment, at cost 6,311.2 6,010.3 Less accumulated depreciation (3,386.3 ) (3,114.6 ) Property, plant and equipment, net $ 2,924.9 $ 2,895.7 The amount of interest capitalized from construction in progress was $2.5 million, $2.5 million, and $2.0 million for the years ended December 31, 2017, 2016, and 2015, respectively. Depreciation is computed on the straight-line basis over the estimated useful lives of the related assets. Assets under capital leases are depreciated on the straight-line method over the term of the lease or the useful life, if shorter. The following lives are used for the various categories of assets: Buildings and land improvements 5 to 40 years Machinery and equipment 3 to 25 years Trucks and automobiles 3 to 10 years Furniture and fixtures 3 to 20 years Computers and hardware 3 to 10 years Leasehold improvements Period of the lease life, if shorter The amount of depreciation expense was $347.8 million, $324.1 million, and $323.0 million for the years ended December 31, 2017, 2016, and 2015, respectively. In 2017, we recognized incremental depreciation expense of $10.5 million, primarily related to the announced second quarter 2018 discontinuation of uncoated free sheet and coated one-side grades at the Wallula, Washington mill associated with the conversion of the No. 3 paper machine to a high-performance 100% virgin kraft linerboard machine. In 2016, we recognized incremental depreciation expense of $2.9 million, primarily related to facilities closure costs and the Wallula, Washington mill restructuring due to the discontinuation of market pulp production. During the year ended December 31, 2015, we recognized $9.0 million of incremental depreciation expense primarily related to shortening the useful lives of assets related to the restructuring at the DeRidder, Louisiana, mill. Pursuant to the terms of an industrial revenue bond, title to certain property, plant, and equipment was transferred to a municipal development authority in 2009 in order to receive a property tax abatement. The title of these assets will revert back to PCA upon retirement or cancellation of the bond. The assets are included in the consolidated balance sheets under the caption “Property, plant, and equipment, net” as all risks and rewards remain with the Company. Leases We assess lease classification as either capital or operating at lease inception or upon modification. We lease some of our locations, as well as other property and equipment, under operating leases. For purposes of determining straight-line rent expense, the lease term is calculated from the date of possession of the facility, including any periods of free rent and any renewal option periods that are reasonably assured of being exercised. Long-Lived Asset Impairment Long-lived assets other than goodwill and other intangibles are reviewed for impairment in accordance with provisions of ASC 360, Property, Plant and Equipment Goodwill and Intangible Assets The Company has capitalized certain intangible assets, primarily goodwill, customer relationships, and trademarks and trade names, based on their estimated fair value at the date of acquisition. Amortization is provided for customer relationships on a straight-line basis over periods ranging from ten to 40 years, and trademarks and trade names over periods ranging from two to 20 years. Goodwill, which amounted to $883.2 million and $737.9 million for the years ended December 31, 2017 and 2016, respectively, is not amortized but is subject to an annual impairment test in accordance with ASC 350, Intangibles - Goodwill and Other Pension and Postretirement Benefits Several estimates and assumptions are required to record pension costs and liabilities, including discount rate, return on assets, and longevity and service lives of employees. We review and update these assumptions annually unless a plan curtailment or other event occurs, requiring we update the estimates on an interim basis. While we believe the assumptions used to measure our pension and postretirement benefit obligations are reasonable, differences in actual experience or changes in assumptions may materially affect our pension and postretirement benefit obligations and future expense. See Note 10, Employee Benefit Plans and Other Postretirement Benefits, for additional information. For postretirement health care plan accounting, the Company reviews external data and its own historical trends for health care costs to determine the health care cost trend rate assumption. Environmental Matters Environmental expenditures that extend the life of the related property or mitigate or prevent future environmental contamination are capitalized. Liabilities are recorded for environmental contingencies when such costs are probable and reasonably estimable. These liabilities are adjusted as further information develops or circumstances change. Environmental expenditures related to existing conditions resulting from past or current operations from which no current or future benefit is discernible are expensed as incurred. Asset Retirement Obligations The Company accounts for its retirement obligations related predominantly to landfill closure, wastewater treatment pond dredging, closed-site monitoring costs, and certain leasehold improvements under ASC 410, Asset Retirement and Environmental Obligations Deferred Financing Costs PCA has capitalized certain costs related to obtaining its financing. These costs are amortized to interest expense using the effective interest rate method over the terms of the related financing, which range from five to ten years. At December 31, 2017 and 2016 deferred financing costs were $15.3 million and $12.4 million, respectively, and were recorded in “Long-Term Debt” on our Consolidated Balance Sheets. Cutting Rights and Fiber Farms We lease the cutting rights to approximately 75,000 acres of timberland, and we lease 9,000 acres of land where we operate fiber farms as a source of future fiber supply. For our cutting rights and fiber farms, we capitalize the annual lease payments and reforestation costs associated with these leases. Costs are recorded as depletion when the timber or fiber is harvested and used in operations or sold to customers. Capitalized long-term lease costs for our cutting rights and fiber farms, primarily recorded in “Other long-term assets” on our Consolidated Balance Sheets, were $31.5 million and $43.9 million as of December 31, 2017 and 2016, respectively. The amount of depletion expense was $5.2 million, $4.7 million, and $7.0 million for the years ended December 31, 2017, 2016, and 2015, respectively. Additionally, in conjunction with the announced conversion of the No. 3 machine at the Wallula mill to kraft linerboard, management performed a recoverability test on associated fiber farms and deemed the asset group to not be fully recoverable. As a result of the recoverability calculation on the fiber farm asset group, the Company recorded an impairment loss of $13.5 million in the third quarter of 2017. Deferred Software Costs PCA capitalizes costs related to the purchase and development of software, which is used in its business operations. The costs attributable to these software systems are amortized over their estimated useful lives based on various factors such as the effects of obsolescence, technology, and other economic factors. Net capitalized software costs recorded in “Other long-term assets” on our Consolidated Balance Sheets were $3.3 million and $4.5 million for the years ended December 31, 2017 and 2016, respectively. Software amortization expense was $2.3 million, $2.5 million, and $3.0 million for the years ended December 31, 2017, 2016, and 2015, respectively. Income Taxes PCA utilizes the liability method of accounting for income taxes whereby it recognizes deferred tax assets and liabilities for the future tax consequences of temporary differences between the tax basis of assets and liabilities and their reported amounts in the financial statements. Deferred tax assets will be reduced by a valuation allowance if, based upon management’s estimates, it is more likely than not that a portion of the deferred tax assets will not be realized in a future period. The estimates utilized in the recognition of deferred tax assets are subject to revision in future periods based on new facts or circumstances. PCA’s practice is to recognize interest and penalties related to unrecognized tax benefits in income tax expense. Trade Agreements PCA regularly trades containerboard with other manufacturers primarily to reduce shipping costs. These agreements are entered into with other producers on an annual basis, pursuant to which both parties agree to ship an identical number of tons of containerboard to each other within the agreement period. These agreements lower transportation costs by allowing each party’s containerboard mills to ship containerboard to the other party’s closer corrugated products plant. PCA tracks each shipment to ensure that the other party’s shipments to PCA match PCA’s shipments to the other party during the agreement period. Such transfers are possible because containerboard is a commodity product with no distinguishing product characteristics. These transactions are accounted for at carrying value, and revenue is not recorded as the transactions do not represent the culmination of an earnings process. The transactions are recorded into inventory accounts, and no sale or income is recorded until such inventory is converted to a finished product and sold to an end-use customer. Business Combinations The Company accounts for acquisitions under ASC 805, Business Combinations Clarifying the Definition of a Business New and Recently Adopted Accounting Standards Effective January 1, 2018, the Company will adopt Financial Accounting Standards Board (“FASB”) ASU 2014-09 (Topic 606): Revenue from Contracts with Customers The Company will adopt the standard utilizing the modified retrospective method, in which case the cumulative effect of applying the standard is recognized at the date of initial application on January 1, 2018. We established a transition team to analyze the impact of the standard on our revenue contracts by reviewing our current accounting policies and practices and identifying potential differences that would result from applying the requirements of the new standard. Specifically, we identified significant revenue streams within each of our reportable segments and reviewed representative contracts to identify corresponding purchase obligations, variable consideration, acquisition costs and fulfillment costs. In addition, we identified and assessed appropriate changes to our business processes, systems and controls to support revenue recognition and disclosures under the new standard. This team has reported its findings and progress of the project to management and the Audit Committee on a periodic basis. During our assessment, the Company considered whether the adoption would require a transition from point-in-time revenue recognition to an over-time approach for products produced by the Company without an alternative use, which would result in acceleration of revenue. The Company determined that based on the express terms included in the majority of its contracts, and the Company’s standard terms and conditions, an enforceable right of payment that includes a reasonable profit throughout the duration of . While the adoption of ASU 2014-09 on January 1, 2018 will not have a material effect on the Company’s financial position or results of operations, the new standard requires additional disclosures around revenue recognition in the notes to the financial statements, which the Company will comply with beginning in 2018. Additionally, the following adjustment and reclassification of certain costs will be made in 2018: a. The b. The Effective January 1, 2017, the Company adopted ASU 2016-09 (Topic 718): Improvements to Employee Share-Based Payment Accounting Effective January 1, 2017, the Company prospectively adopted ASU 2015-11 (Topic 330): Simplifying the Measurement of Inventory In January 2017, the FASB issued ASU 2017-04 (Topic 350): Intangibles - Goodwill and Other - Simplifying the Test for Goodwill Impairment In March 2017, the FASB issued ASU 2017-07, Compensation: Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost. In May 2017, the FASB issued ASU 2017-09 Compensation - Stock Compensation Scope of Modification Accounting In January 2017, the FASB issued ASU 2017-01 (Topic 805): Clarifying the Definition of a Business In August 2016, the FASB issued ASU 2016-15 (Topic 230), Statement of Cash Flows: Classification of Certain Cash Receipts and Cash Payments In February 2016, the FASB issued ASU 2016-02 (Topic 842): Leases There were no other accounting standards recently issued that had or are expected to have a material impact on our financial position or results of operations.

Acquisitions and Dispositions

Acquisitions and Dispositions	12 Months Ended
	Dec. 31, 2017
Business Combinations [Abstract]
Acquisitions and Dispositions	3. Acquisitions Sacramento Container Acquisition On October 2, 2017, PCA acquired substantially all of the assets of Sacramento Container Corporation, and 100% of the membership interests of Northern Sheets, LLC and Central California Sheets, LLC (collectively referred to as “Sacramento Container”) for a purchase price of $265 million. Funding for the $265 million purchase price came from available cash on hand. Assets acquired include full-line corrugated products and sheet feeder operations in both McClellan, California and Kingsburg, California. Sacramento Container provides packaging solutions to customers serving portions of California’s strong agricultural market. Sacramento Container’s financial results are included in the Packaging segment from the date of acquisition. For the period ended December 31, 2017, Sacramento Container accounted for $58.5 million, or 1%, of the Company’s net sales. Had the acquisition occurred at the beginning of 2016, the Company’s net sales would have been $6.6 billion and $6.0 billion for 2017 and 2016, respectively. The Company accounted for the Sacramento Container acquisition using the acquisition method of accounting in accordance with ASC 805, Business Combinations Initial Allocation Adjustments Revised Allocation Goodwill $ 151.1 $ — $ 151.1 Other intangible assets 72.6 — 72.6 Property, plant and equipment 26.7 — 26.7 Other net assets 14.6 8.8 23.4 Net assets acquired $ 265.0 $ 8.8 $ 273.8 In October of 2017, we increased the purchase price by $8.8 million as a result of a working capital adjustment paid to the seller. We recorded the adjustment as an $8.8 million increase to other net assets acquired. The purchase price above is preliminary and is subject to the finalization of various valuations and assessments, primarily related to property, plant, and equipment and intangible assets. Our current estimates and assumptions may change as more information becomes available. We expect to finalize the valuation within the 12-month period following the acquisition date. Goodwill is calculated as the excess of the purchase price over the fair value of the net assets acquired. Among the factors that contributed to the recognition of goodwill were Sacramento Container’s commitment to continuous improvement and regional synergies, as well as the expected increases in PCA's containerboard integration levels. Goodwill is deductible for tax purposes. Other intangible assets, primarily customer relationships, were assigned an estimated weighted average useful life of 9.7 years. Property, plant and equipment were assigned estimated useful lives ranging from one to 13 years. Columbus Container Acquisition On November 30, 2016, PCA acquired substantially all of the assets of Columbus Container, Inc., an independent corrugated products producer with one corrugated products production facility and five warehousing facilities, for a purchase price of $99.7 million, net of cash acquired. We paid the purchase price with available cash on hand. Columbus Container is a full-service provider of corrugated packaging products utilizing state-of-the-art technologies and design centers to provide customers a solution for nearly any packaging need. Columbus Container’s financial results are included in the Packaging segment from the date of acquisition. The Company accounted for the Columbus Container acquisition using the acquisition method of accounting in accordance with ASC 805, Business Combinations 12/31/16 Allocation Adjustments Revised Allocation Goodwill $ 36.6 $ (4.7 ) $ 31.9 Other intangible assets 26.3 6.0 32.3 Property, plant and equipment 27.2 1.0 28.2 Other net assets 9.6 (0.1 ) 9.5 Net assets acquired $ 99.7 $ 2.2 $ 101.9 During the third quarter of 2017, we increased the purchase price by $2.2 million as a result of a working capital adjustment paid to the seller. We recorded the adjustment as a $2.2 million increase to goodwill. Goodwill is calculated as the excess of the purchase price over the fair value of the net assets acquired. Among the factors that contributed to the recognition of goodwill were Columbus Container's commitment to continuous improvement and innovation in their operations, as well as the expected increases in PCA's containerboard integration levels. Goodwill is deductible for tax purposes. Other intangible assets, primarily customer relationships, were assigned an estimated weighted average useful life of 14.1 years. Property, plant and equipment were assigned estimated useful lives ranging from one to 32 years. TimBar Acquisition On August 29, 2016, PCA acquired substantially all of the assets of TimBar Corporation (“TimBar”), a large independent corrugated products producer with six corrugated products production facilities, for a purchase price of $385.6 million, net of cash acquired. We financed the acquisition with a new $385.0 million five-year term loan facility. TimBar provides solutions to customers in the higher margin retail, industrial packaging and display and fulfillment markets with a focus on multi-color graphics and technical innovation. TimBar’s financial results are included in the Packaging segment from the date of acquisition. The Company accounted for the TimBar acquisition using the acquisition method of accounting in accordance with ASC 805, Business Combinations 12/31/16 Allocation Adjustments Revised Allocation Goodwill $ 157.3 $ (1.1 ) $ 156.2 Other intangible assets 94.4 94.4 Property, plant and equipment 95.3 95.3 Other net assets 38.6 38.6 Net assets acquired $ 385.6 $ (1.1 ) $ 384.5 During the first quarter of 2017, we received $1.1 million from the seller related to a working capital adjustment. We recorded the adjustment as a decrease to goodwill which lowered the purchase price to $384.5 million. Goodwill is calculated as the excess of the purchase price over the fair value of the net assets acquired. Among the factors that contributed to the recognition of goodwill were TimBar's commitment to continuous improvement and innovation in their operations, as well as the expected increases in PCA's containerboard integration levels. Goodwill is deductible for tax purposes. Other intangible assets, primarily customer relationships, were assigned an estimated weighted average useful life of 14.2 years. Property, plant and equipment were assigned estimated useful lives ranging from two to 24 years.

Earnings Per Share

Earnings Per Share	12 Months Ended
	Dec. 31, 2017
Earnings Per Share [Abstract]
Earnings Per Share	4. Earnings Per Share The following table sets forth the computation of basic and diluted income per common share for the periods presented (dollars and shares in millions, except per share data). Year Ended December 31 2017 2016 2015 Numerator: Net income $ 668.6 $ 449.6 $ 436.8 Less: distributed and undistributed earnings allocated to participating securities (5.6 ) (4.4 ) (5.2 ) Net income attributable to common stockholders $ 663.0 $ 445.2 $ 431.6 Denominator: Weighted average common shares outstanding 93.5 93.5 96.6 Effect of dilutive securities 0.2 0.2 0.1 Diluted common shares outstanding 93.7 93.7 96.7 Basic income per common share $ 7.09 $ 4.76 $ 4.47 Diluted income per common share $ 7.07 $ 4.75 $ 4.47

Other Expense, Net

Other Expense, Net	12 Months Ended
	Dec. 31, 2017
Other Income And Expenses [Abstract]
Other Expense, Net	5. Other Expense, Net The components of other income (expense), net, were as follows (dollars in millions) Year Ended December 31, 2017 2016 2015 Wallula mill restructuring (a) $ (23.1 ) $ — $ — Asset disposals and write-offs (10.5 ) (11.9 ) (14.0 ) Acquisition and integration related costs (b)(c)(d) (0.8 ) (3.3 ) (12.9 ) Expiration of timberland repurchase option (e) 2.0 — — Hexacomb working capital adjustment (f) 2.3 — — Facilities closure and other costs (g) 5.9 (10.3 ) — DeRidder mill incident (h) 9.7 — — Ceased production of market pulp at Wallula (i) — (0.6 ) — DeRidder restructuring (j) — — 7.1 Sale of St. Helens Paper Mill Site (k) — — 6.7 Refundable state tax credit (l) — — 3.6 Other (3.9 ) 1.8 2.8 Total $ (18.4 ) $ (24.3 ) $ (6.7 ) (a) Includes $23.1 million of charges related to our determination to discontinue production of uncoated free sheet and coated one-side grades at the Wallula, Washington mill in the second quarter of 2018 and convert the No. 3 paper machine to a high-performance 100% virgin kraft linerboard machine. (b) For 2017, includes charges related to the Sacramento Container Corporation acquisition and integration costs related to other recent acquisitions. (c) For 2016, includes charges related to the acquisition and integration of TimBar Corporation. (d) For 2015, includes Boise acquisition integration-related and other costs, which primarily relate to severance, retention, travel, and professional fees. (e) Includes a gain related to the expiration of a repurchase option corresponding to timberland previously sold. (f) Includes income related to a working capital adjustment from the April 2015 sale of our Hexacomb corrugated manufacturing operations in Europe and Mexico. (g) For 2017, includes income primarily related to the sale of land corresponding to the closure of a corrugated products facility, partially offset by closure costs related to corrugated products facilities, a paper administration facility, a corporate administration facility, and a lump sum settlement of a multiemployer pension plan withdrawal liability for one of our corrugated products facilities. For 2016, includes expenses related to the closure of corrugated products facilities and a paper administration facility and a lump sum settlement of a multiemployer pension plan withdrawal liability for one of our corrugated products facilities. (h) Includes the property damage and business interruption insurance recoveries and corresponding costs related to the February 2017 explosion at our DeRidder, Louisiana mill. (i) Includes costs related to ceased softwood market pulp operations at our Wallula, Washington mill and the permanent shutdown of the No. 1 machine. (j) Includes $7.1 million of income from vendor settlements related to our restructuring activities at our DeRidder, Louisiana mill. (k) Includes a gain related to the sale of the remaining land, buildings, and equipment at our paper mill site in St. Helens, Oregon where we ceased paper production in December 2012. (l) Includes a tax credit from the State of Louisiana related to capital investment and the jobs retained at the DeRidder, Louisiana mill.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Income Taxes	6. Income Taxes On December 22, 2017, the President signed into law H.R.1 (P.L. 115-97), originally known as the “Tax Cuts and Jobs Act” (the “Tax Act”). The Tax Act significantly revises the U.S. tax code by, among other items, reducing the federal corporate tax rate from 35% to 21%, providing for the full expensing of certain depreciable property, eliminating the corporate alternative minimum tax, limiting the deductibility of interest expense, further limiting the deductibility of certain executive compensation, limiting the use of net operating loss carryforwards created in tax years beginning after December 31, 2017, and implementing a territorial tax system imposing a deemed repatriation transition tax (“Transition Tax”) on earnings of foreign subsidiaries. Generally accepted accounting principles require companies to record the impact of the Tax Act in their financial statements for the period during which the Tax Act becomes law, even if provisions of the Tax Act become effective at a future date. The SEC staff recently issued Staff Accounting Bulletin (“SAB”) 118, Income Tax Accounting Implications of the Tax Cuts and Jobs Act, which provides guidance on accounting for the effects and includes a measurement period that ends when a company has obtained, prepared and analyzed the information necessary to finalize its accounting of the Tax Act which cannot extend beyond one year. In accordance with SAB 118, a company must reflect the income tax effects of those aspects of the Tax Act for which the accounting under ASC 740, Income Taxes, is complete. To the extent that a company’s accounting for certain income tax effects of the Tax Act is incomplete, but it is able to determine a reasonable estimate, it must record a provisional estimate in the financial statements. If a company cannot determine a provisional estimate to be included in the financial statements, it should continue to apply ASC 740 on the basis of the provisions of the tax laws that were in effect immediately before the enactment of the Tax Act. Based on currently available information, the Tax Act resulted in a one-time total net tax benefit of $122.1 million in the period ending December 31, 2017, primarily related to the re-measurement of our U.S. deferred tax assets and liabilities to the lower enacted corporate tax rate for $128.0 million offset by a reduction in the domestic manufacturers deduction for $5.1 million, the Transition Tax and other current year tax reform impacts of $0.8 million. Our accounting for the following elements of the Tax Act are not yet complete; however, we were able to make reasonable estimates of certain effects and, therefore, recorded provisional adjustments. These estimates may be affected by additional analysis and are subject to change due to a variety of factors, including, among others: (i) management’s further assessment of the Tax Act and related regulatory guidance; (ii) further guidance that may be issued by the Treasury, Financial Accounting Standards Board, Securities and Exchange Commission, Internal Revenue Service, or state, local or other taxing authorities; and (iii) actions the Company may take as a result of the Tax Act. Re-measurement of Net Deferred Tax Liability: As a result of the Company’s net deferred tax liability position, we have recorded a one-time provisional income tax benefit of $128.0 million for the year ended December 31, 2017, as a result of the reduction in the federal corporate tax rate. Cost Recovery: While we have not yet completed a full analysis of our 2017 capital expenditures that could qualify for immediate expensing, we have recorded a provisional benefit for bonus depreciation that resulted in a decrease of approximately $24.6 million to our current income taxes payable and a corresponding increase in our deferred tax liabilities (after considering the effects of the reduction in the federal corporate tax rate). Deemed Repatriation Transition Tax: The Transition Tax is a tax on previously untaxed accumulated and current earnings and profits (“E&P”) of certain of our foreign subsidiaries. To determine the amount of the Transition Tax, we must determine, in addition to other factors, the amount of post-1986 E&P of the relevant subsidiaries, as well as the amount of non-U.S. income taxes paid on such earnings. We were able to make a reasonable estimate of the Transition Tax and recorded a provisional Transition Tax obligation of approximately $0.1 million. The Company believes the impact of certain foreign related provisions in the Tax Act, such as the base erosion anti-abuse tax (“BEAT”), the tax on global intangible low-taxed income (“GILTI”), and the reduced rate of tax on certain foreign-derived intangible income (“FDII”), will be immaterial based on our primarily domestic operations. The impact of certain domestic related provisions in the Tax Act, such as the limitation on interest expense deductibility and net operating loss carryforwards will also be immaterial. The Company will continue to analyze the impact on future periods of the limitation on the deductibility of certain executive compensation. The Company estimates, based on forecasted 2018 results, that its combined federal and state effective tax rate will be in the range of 24% to 26%. The following is an analysis of the components of the consolidated income tax provision (dollars in millions): Year Ended December 31 2017 2016 2015 Current income tax provision (benefit) - U.S. federal $ 209.3 $ 213.6 $ 205.1 State and local 34.9 29.1 20.5 Foreign 0.3 0.2 0.4 Total current provision for taxes 244.5 242.9 226.0 Deferred - U.S. federal (90.2 ) (1.2 ) (3.8 ) State and local 5.7 (3.0 ) 5.6 Foreign — 0.2 (0.1 ) Total deferred provision (benefit) for taxes (84.5 ) (4.0 ) 1.7 Total provision (benefit) for taxes $ 160.0 $ 238.9 $ 227.7 The effective tax rate varies from the U.S. federal statutory tax rate principally due to the following (dollars in millions): 2017 2016 2015 Provision computed at U.S. federal statutory rate of 35% $ 290.0 $ 241.0 $ 232.6 Federal tax reform (127.2 ) — — State and local taxes, net of federal benefit 24.0 19.8 20.0 Domestic manufacturers deduction (21.1 ) (21.1 ) (19.9 ) Other (5.7 ) (0.8 ) (5.0 ) Total $ 160.0 $ 238.9 $ 227.7 The following details the scheduled expiration dates of our tax effected net operating loss (NOL) and other tax carryforwards at December 31, 2017 (dollars in millions): 2018 Through 2027 2028 Through 2037 Indefinite Total U.S. federal NOLs $ — $ 35.8 $ — $ 35.8 State taxing jurisdiction NOLs 1.4 0.9 — 2.3 U.S. federal tax credit carryforwards — 0.1 — 0.1 U.S. federal and non-U.S. capital loss carryforwards 3.0 — 0.1 3.1 Total $ 4.4 $ 36.8 $ 0.1 $ 41.3 Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts for income tax purposes. Deferred income tax assets and liabilities at December 31 are summarized as follows (dollars in millions): December 31 2017 2016 Deferred tax assets: Accrued liabilities $ 13.7 $ 18.1 Employee benefits and compensation 21.1 45.9 Inventories 15.4 9.9 Net operating loss carryforwards 38.1 67.4 Restricted stock and performance units 9.0 11.7 Pension and postretirement benefits 90.6 136.5 Derivatives 6.1 11.5 Capital loss and general business credit carryforwards 3.2 5.3 Gross deferred tax assets $ 197.2 $ 306.3 Valuation allowance (a) (3.1 ) (5.2 ) Net deferred tax assets $ 194.1 $ 301.1 Deferred tax liabilities: Property, plant and equipment $ (368.6 ) $ (537.0 ) Goodwill and intangible assets (65.0 ) (98.8 ) Total deferred tax liabilities $ (433.6 ) $ (635.8 ) Net deferred tax liabilities (b) $ (239.5 ) $ (334.7 ) (a) Deferred tax assets are reduced by a valuation allowance when it is more likely than not that some portion of the deferred tax assets will not be realized. Both the 2017 and 2016 valuation allowance relates to capital losses. We do not expect to generate capital gains before the capital losses expire. If or when recognized, the tax benefits relating to the reversal of any or all of the valuation allowance would be recognized as a benefit to income tax expense. (b) As of December 31, 2017, we did not recognize U.S. deferred income taxes on our cumulative total of undistributed foreign earnings for our foreign subsidiaries. We indefinitely reinvest our earnings in operations outside the United States. It is not practicable to determine the amount of unrecognized deferred tax liability on these undistributed earnings because the actual tax liability, if any, is dependent on circumstances existing when the repatriation occurs. Cash payments for federal, state, and foreign income taxes were $298.7 million, $222.1 million, and $238.3 million for the years ended December 31, 2017, 2016, and 2015, respectively. The following table summarizes the changes related to PCA’s gross unrecognized tax benefits excluding interest and penalties (dollars in millions): 2017 2016 2015 Balance as of January 1 $ (5.2 ) $ (5.8 ) $ (4.4 ) Increases related to prior years’ tax positions — — (2.8 ) Increases related to current year tax positions (0.4 ) (0.5 ) (0.4 ) Decreases related to prior years' tax positions — 0.1 — Settlements with taxing authorities — 0.3 0.7 Expiration of the statute of limitations 0.8 0.7 1.1 Balance at December 31 $ (4.8 ) $ (5.2 ) $ (5.8 ) At December 31, 2017, PCA had recorded a $4.8 million gross reserve for unrecognized tax benefits, excluding interest and penalties. Of the total, $4.2 million (net of the federal benefit for state taxes) would impact the effective tax rate if recognized. PCA recognizes interest accrued related to unrecognized tax benefits and penalties as income tax expense. For both years ended December 31, 2017 and 2016, we had $1.1 million of interest and penalties recorded for unrecognized tax benefits. During the next 12 months, it is reasonably possible that PCA's unrecognized tax benefits related to state apportionment issues could decrease by approximately $3.1 million due to settlements with state taxing authorities. PCA is subject to taxation in the United States, various state and local, and foreign jurisdictions. A federal examination of the tax years 2010 - 2012 was concluded in February 2015. A federal examination of the 2013 tax year was concluded in November 2016. The tax years 2014 - 2017 remain open to federal examination. The tax years 2013 - 2017 remain open to state examinations. Some foreign tax jurisdictions are open to examination for the 2009 tax year forward. Through the Boise acquisition, PCA recorded net operating losses and credit carryforwards from 2008 through 2011 and 2013 that are subject to examinations and adjustments for at least three years following the year in which utilized.

Goodwill and Intangible Assets

Goodwill and Intangible Assets	12 Months Ended
	Dec. 31, 2017
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	7. Goodwill and Intangible Assets Goodwill Goodwill represents the excess of the cost of an acquired business over the fair value of the identifiable tangible and intangible assets acquired and liabilities assumed in a business combination. At December 31, 2017 and 2016, we had $828.0 million and $682.7 million, respectively, of goodwill recorded in our Packaging segment and $55.2 million for both years in our Paper segment on our Consolidated Balance Sheets. Changes in the carrying amount of our goodwill were as follows (dollars in millions): Packaging Paper Goodwill Balance at January 1, 2016 $ 488.8 $ 55.2 $ 544.0 Acquisitions (a) 193.9 — 193.9 Balance at December 31, 2016 $ 682.7 $ 55.2 $ 737.9 Acquisitions (b)(c) 145.3 — 145.3 Balance at December 31, 2017 $ 828.0 $ 55.2 $ 883.2 (a) In connection with the August 2016 acquisition of TimBar, the Company recoded $157.3 million of goodwill in the Packaging segment. In November 2016, we acquired Columbus Container and recorded $36.6 million of goodwill in the Packaging segment. (b) In connection with the October 2017 acquisition of Sacramento Container, the Company recorded $151.1 million of goodwill in the Packaging segment. (c) During 2017, the Company recorded opening balance sheet adjustments related to the TimBar and Columbus Container acquisitions resulting in a decrease to goodwill of $5.8 million. See Note 3, Acquisitions, for more information. Intangible Assets Intangible assets are comprised of customer relationships and trademarks and trade names. The weighted average useful life, gross carrying amount, and accumulated amortization of our intangible assets were as follows (dollars in millions): As of December 31, 2017 As of December 31, 2016 Weighted Average Useful Life (in Years) Gross Carrying Amount Accumulated Amortization Weighted Average Remaining Useful Life (in Years) Gross Carrying Amount Accumulated Amortization Customer relationships (d) 11.8 $ 497.8 $ 109.8 13.1 $ 424.5 $ 79.8 Trademarks and trade names (d) 9.8 32.9 13.2 10.5 27.7 8.1 Other (d) 3.6 4.3 2.0 4.3 4.2 1.4 Total intangible assets (excluding goodwill) 11.7 $ 535.0 $ 125.0 12.9 $ 456.4 $ 89.3 (d) In connection with the October 2017 acquisition of Sacramento Container, the Company recorded intangible assets of $68.4 million for customer relationships, $4.1 million for trade names, and $0.1 million for other intangibles. In August 2016, we acquired TimBar and recorded intangible assets of $88.0 million for customer relationships, $4.9 million for trade names, and $1.5 million for other intangibles. In November 2016, we acquired Columbus Container and recorded intangible assets of $30.0 million for customer relationships, $2.2 million for trade names, and $0.2 million for other intangibles. See Note 3, Acquisitions, for more information. Amortization expense was $35.7 million, $26.6 million, and $22.7 million for the years ended December 31, 2017, 2016, and 2015, respectively. Estimated amortization expense of intangible assets over the next five years is expected to approximate $40.4 million (2018), $37.8 million (2019), $37.7 million Impairment Testing We test goodwill for impairment annually in the fourth quarter or sooner if events or changes in circumstances indicate that the carrying value of the asset may exceed fair value. Additionally, when we experience changes to our business or operating environment, we evaluate the remaining useful lives and recoverability of our finite-lived purchased intangible assets to determine whether any adjustments to the useful lives or impairment are necessary. We completed our test in the fourth quarter and there was no indication of goodwill or intangible asset impairment.

Accrued Liabilities

Accrued Liabilities	12 Months Ended
	Dec. 31, 2017
Accrued Liabilities Current And Noncurrent [Abstract]
Accrued Liabilities	8. Accrued Liabilities The components of accrued liabilities were as follows (dollars in millions): December 31, 2017 2016 Compensation and benefits $ 127.5 $ 120.4 Medical insurance and workers’ compensation 23.9 28.8 Customer volume discounts and rebates 23.4 18.9 Franchise, property, sales and use taxes 16.0 16.7 Environmental liabilities and asset retirement obligations 4.0 6.4 Severance, retention, and relocation 3.1 3.0 Other 5.3 7.0 Total $ 203.2 $ 201.2

Debt

Debt	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Debt	9. Debt At December 31, 2017 and 2016, our long-term debt and interest rates on that debt were as follows (dollars in millions): December 31, 2017 December 31, 2016 Amount Interest Rate Amount Interest rate Revolving Credit Facility, due August 2021 $ — — % $ — — % Five-Year Term Loan, due August 2021 — — % 380.2 2.02 % Seven-Year Term Loan, due October 2020 — — % 630.5 2.40 % 6.50% Senior Notes due March 2018 150.0 6.50 % 150.0 6.50 % 2.45% Senior Notes, net of discount of $0.5 million as of December 31, 2017 due December 2020 499.5 2.45 % — — % 3.90% Senior Notes, net of discounts of $0.2 million and $0.2 million as of December 30, 2017 and 2016, respectively, due June 2022 399.8 3.90 % 399.8 3.90 % 4.50% Senior Notes, net of discount of $1.2 million a $1.4 million as of December 30, 2017 and 2016, respectively, due November 2023 698.8 4.50 % 698.6 4.50 % 3.65% Senior Notes, net of discount of $0.8 million and $0.9 million as of December 31, 2017 and 2016, respectively, due September 2024 399.2 3.65 % 399.1 3.65 % 3.40% Senior Notes, net of discount of $1.6 million as of December 31, 2017 due December 2027 498.4 3.40 % — — % Total 2,645.7 3.80 % 2,658.2 3.54 % Less current portion 150.0 6.50 % 25.8 2.11 % Less unamortized debt issuance costs 15.3 12.5 Total long-term debt $ 2,480.4 3.64 % $ 2,620.0 3.57 % On December 13, 2017, the Company issued $500.0 million of 2.45% senior notes due 2020 and $500.0 million of 3.40% senior notes due 2027, through a registered public offering. The net proceeds of $997.8 million were used to repay in full all amounts outstanding under our Seven-Year term loan due October 2020 of $625.6 million and our Five-Year term loan due August 2021 of $350.4 million. Any remaining net proceeds were used to pay $6.8 million of debt issuance costs and for general corporate purposes. The debt issuance costs will be amortized to interest expense using the effective interest method over the terms of the notes. As of December 31, 2017, the details of our borrowings were as follows: • Senior Unsecured Credit Agreement . On October 18, 2013, we entered into a $1.65 billion senior unsecured credit facility. Loans bear interest at LIBOR plus a margin that is determined based upon our credit ratings. On August 29, 2016, we amended and restated our five-year credit agreement dated October 18, 2013 to include a new five-year $385 million term loan facility to finance the acquisition of TimBar Corporation and to extend the maturity of the revolving credit facility to 2021. The financing consisted of: • Revolving Credit Facility : A $350.0 million unsecured revolving credit facility with variable interest (LIBOR plus a margin) due August 2021. During 2017, we did not borrow under the Revolving Credit Facility. At December 31, 2017, we had $23.1 million of outstanding letters of credit that were considered outstanding on the revolving credit facility, resulting in $326.9 million of unused borrowing capacity. The outstanding letters of credit were primarily for workers compensation. We are required to pay commitment fees on the unused portions of the credit facility. • Five-Year Term Loan: A $385.0 million unsecured five-year term loan with variable interest (LIBOR plus 1.250%), payable quarterly, due August 2021. The term loan was repaid on December 13, 2017 with the proceeds received from the note offering discussed above. • Seven-Year Term Loan : A $650.0 million unsecured term loan with variable interest (LIBOR plus 1.625%), payable quarterly, due October 2020. The term loan was repaid on December 13, 2017 with the proceeds received from the note offering discussed above. • 6.50% Senior Notes. On March 25, 2008, we issued $150.0 million of 6.50% senior notes due March 15, 2018, through a registered public offering. • 3.90% Senior Notes. On June 26, 2012, we issued $400.0 million of 3.90% senior notes due June 15, 2022, through a registered public offering. • 4.50% Senior Notes . On October 22, 2013, we issued $700.0 million of 4.50% senior notes due November 1, 2023, through a registered public offering. • 3.65% Senior Notes. On September 5, 2014, we issued $400.0 million of 3.65% senior notes due September 15, 2024, through a registered public offering. • 2.45% Senior Notes. On December 13, 2017, we issued $500.0 million of 2.45% senior notes due December 15, 2020, through a registered public offering. • 3.40% Senior Notes. On December 13, 2017, we issued $500.0 million of 3.40% senior notes due December 15, 2027, through a registered public offering. The instruments governing our indebtedness contain financial and other covenants that limit the ability of PCA and its subsidiaries to enter into sale and leaseback transactions, incur liens, incur indebtedness at the subsidiary level, enter into certain transactions with affiliates, merge or consolidate with any other person or sell or otherwise dispose of all or substantially all of our assets. Our credit facility also requires us to comply with certain financial covenants, including maintaining a minimum interest coverage ratio and a maximum leverage ratio. A failure to comply with these restrictions could lead to an event of default, which could result in an acceleration of any outstanding indebtedness and/or prohibit us from drawing on the revolving credit facility. Such an acceleration may also constitute an event of default under the senior notes indenture. At December 31, 2017, we were in compliance with these covenants. At December 31, 2017, we have $2,645.7 million of fixed-rate senior notes outstanding. At December 31, 2017, the fair value of our fixed-rate debt was estimated to be $2,734.9 million. The difference between the book value and fair value is due to the difference between the period-end market interest rate and the stated rate of our fixed-rate debt. We estimated the fair value of our fixed-rate debt using quoted market prices (Level 2 inputs), discussed further in Note 2, Summary of Significant Accounting Policies. Repayments, Interest, and Other In 2017, we used the net proceeds from our 2.45% and 3.40% senior note offerings and other cash on hand to repay debt outstanding of $630.5 million under the Seven-Year Term Loan due October 2020 and $380.2 million under the Five-Year Term Loan due August 2021, both of which are no longer outstanding. In 2016, we used cash on hand to make principal payments of $25.0 million under our old Five-Year Term Loan, $4.8 million under the new Five-Year Term Loan entered into in 2016, due August 2021, and $6.5 million under the Seven-Year Term Loan, due October 2020. In 2015, we used cash on hand to repay $40.0 million of debt outstanding under our old Five-Year Term Loan and $6.5 million under the Seven-Year Term Loan, due October 2020. As of December 31, 2017, annual principal maturities for debt, excluding unamortized debt discount, are: $150.0 million for 2018 which we intend to repay from cash on hand at maturity in March 2018; none for 2019; $500.0 million for 2020; none for 2021; $400.0 million for 2022; and $1.6 billion for 2023 and thereafter. Interest payments paid in connection with the Company’s debt obligations for the years ended December 31, 2017, 2016, and 2015, were $96.3 million, $88.3 million, and $85.5 million, respectively. Included in interest expense, net, are amortization of financing costs and amortization of treasury lock settlements. Amortization of treasury lock settlements was a $5.7 million net loss in 2017, 2016, and 2015. Amortization of financing costs in 2017, 2016, and 2015 was $4.0 million (including a $1.8 million write-off of deferred debt issuance costs related to the December 2017 debt refinancing), $1.8 million, and $1.8 million, respectively.

Employee Benefit Plans and Othe

Employee Benefit Plans and Other Postretirement Plans	12 Months Ended
	Dec. 31, 2017
Compensation And Retirement Disclosure [Abstract]
Employee Benefit Plans and Other Postretirement Benefits	10. Employee Benefit Plans and Other Postretirement Benefits PCA has defined pension benefit plans for both salaried and hourly employees. The plans covering salaried employees are closed to new entrants with only certain current active participants still accruing benefits. The plans covering certain hourly employees are closed to new participants. We also have a Supplemental Executive Retirement Plan (SERP) and other nonqualified defined benefit pension plans that provide unfunded supplemental retirement benefits to certain of our executives and former executives. The SERP provides for incremental pension benefits in excess of those offered in our principal pension plans. Other Postretirement Benefits PCA provides postretirement medical benefits for certain salaried employees and postretirement medical and life insurance benefits for certain hourly employees. For salaried employees, the plan covers employees retiring from PCA on or after attaining age 58 who have had at least 10 years of full-time service with PCA after attaining age 48. In April 2016, the Company provided notice to eligible participants that the Salaried Retiree Medical Plan would be frozen as of December 31, 2016. As a result of the freeze, eligible plan participants who did not retire and elect coverage before December 31, 2016 would lose benefits attributable to service already rendered. In accordance with Accounting Standards Codification (ASC) 715, “Compensation--Retirement Benefits”, the Company remeasured the Salaried Retiree Medical Plan benefit obligation using current assumptions, resulting in a decrease in the benefit obligation of $5.1 million with a corresponding increase in accumulated other comprehensive income of $3.1 million and deferred income taxes of $2.0 million. Obligations and Funded Status of Defined Benefit Pension and The funded status of PCA's plans change from year to year based on the plan asset investment return, contributions, benefit payments, the discount rate used to measure the liability, and expected participant longevity. The following table, which includes only company-sponsored defined benefit and other postretirement benefit plans, reconciles the beginning and ending balances of the projected benefit obligation and the fair value of plan assets. We recognize the unfunded status of these plans on the Consolidated Balance Sheets, and we recognize changes in funded status in the year changes occur through the Consolidated Statements of Comprehensive Income (dollars in millions): Pension Plans Postretirement Plans Year Ended December 31 Year Ended December 31 2017 2016 2017 2016 Change in Benefit Obligation Benefit obligation at beginning of period $ 1,158.4 $ 1,092.5 $ 19.5 $ 21.4 Service cost 23.7 24.5 0.3 0.5 Interest cost 41.6 40.9 0.6 0.6 Plan amendments 17.3 1.8 (0.5 ) (5.3 ) Actuarial loss (gain) (a) 99.3 35.3 (2.2 ) 3.7 Participant contributions — — 1.3 1.3 Benefits paid (40.1 ) (36.6 ) (2.5 ) (2.7 ) Benefit obligation at plan year end $ 1,300.2 $ 1,158.4 $ 16.5 $ 19.5 Accumulated benefit obligation portion of above $ 1,237.7 $ 1,116.6 Change in Fair Value of Plan Assets Plan assets at fair value at beginning of period $ 830.4 $ 764.4 $ — $ — Actual return on plan assets 121.0 44.4 — — Company contributions 43.5 58.2 1.2 1.4 Participant contributions — — 1.3 1.3 Benefits paid (40.1 ) (36.6 ) (2.5 ) (2.7 ) Fair value of plan assets at plan year end $ 954.8 $ 830.4 $ — $ — Underfunded status $ (345.4 ) $ (328.0 ) $ (16.5 ) $ (19.5 ) Amounts Recognized on Consolidated Balance Sheets Current liabilities $ (1.4 ) $ (1.3 ) $ (1.0 ) $ (1.2 ) Noncurrent liabilities (344.0 ) (326.7 ) (15.5 ) (18.3 ) Accrued obligation recognized at December 31 $ (345.4 ) $ (328.0 ) $ (16.5 ) $ (19.5 ) Amounts Recognized in Accumulated Other Comprehensive Loss (Income) (Pre-Tax) Prior service cost (credit) $ 32.7 $ 21.1 $ (5.3 ) $ (5.0 ) Actuarial loss (gain) 208.5 183.9 (4.0 ) (1.9 ) Total $ 241.2 $ 205.0 $ (9.3 ) $ (6.9 ) (a) The actuarial loss in 2017 was due primarily to a decrease in the weighted average discount rate used to estimate our pension benefit obligations. In 2016, a decrease in the weighted average discount rate used to estimate our pension benefit obligations and changes in mortality assumptions from the Society of Actuaries resulted in an actuarial loss. Components of Net Periodic Benefit Cost and Other Comprehensive (Income) Loss The components of net periodic benefit cost and other comprehensive (income) loss (pretax) were as follows (dollars in millions): Pension Plans Postretirement Plans Year Ended December 31 Year Ended December 31 2017 2016 2015 2017 2016 2015 Service cost $ 23.7 $ 24.5 $ 24.0 $ 0.3 $ 0.5 $ 1.7 Interest cost 41.6 40.9 46.2 0.6 0.6 1.2 Expected return on plan assets (53.9 ) (49.5 ) (53.1 ) — — — Net amortization of unrecognized amounts Prior service cost (credit) 5.8 5.7 5.5 (0.2 ) (0.1 ) 0.1 Actuarial loss (gain) 7.6 5.8 8.7 (0.1 ) (0.4 ) 0.1 Net periodic benefit cost $ 24.8 $ 27.4 $ 31.3 $ 0.6 $ 0.6 $ 3.1 Changes in plan assets and benefit obligations recognized in other comprehensive (income) loss Actuarial net loss (gain) $ 32.2 $ 40.4 $ (14.5 ) $ (2.2 ) $ 3.6 $ (11.4 ) Prior service cost (credit) 17.4 1.8 3.0 (0.6 ) (5.3 ) — Amortization of prior service cost (credit) (5.8 ) (5.7 ) (5.5 ) 0.2 (0.3 ) (0.1 ) Amortization of actuarial loss (gain) (7.6 ) (5.8 ) (8.7 ) 0.1 0.8 (0.1 ) Total recognized in other comprehensive loss (income) (a) $ 36.2 $ 30.7 $ (25.7 ) $ (2.5 ) $ (1.2 ) $ (11.6 ) Total recognized in net periodic benefit cost and other comprehensive loss (income) (pre-tax) $ 61.0 $ 58.1 $ 5.6 $ (1.9 ) $ (0.6 ) $ (8.5 ) (a) Accumulated losses in excess of 10% of the greater of the projected benefit obligation or the market-related value of assets will be recognized on a straight-line basis over the average remaining service period of active employees in PCA plans (which is between seven to ten years) and over the average remaining lifetime of inactive participants of Boise plans (which is between 25 and 28 years), to the extent that losses are not offset by gains in subsequent years. The estimated net loss and prior service cost that will be amortized from “Accumulated other comprehensive loss” into net periodic benefit in 2018 is $15.8 million. The accumulated benefit obligations for the plans with obligations in excess of plan assets, is $1.2 billion. Assumptions The following table presents the assumptions used in the measurement of our benefits obligations: Pension Plans Postretirement Plans December 31 December 31 2017 2016 2015 2017 2016 2015 Weighted-Average Assumptions Used to Determine Benefit Obligations at December 31 Discount rate 3.66% 4.24% 4.51% 3.55% 3.91% 4.35% Rate of compensation increase 4.00% 4.00% 4.00% N/A N/A N/A Weighted-Average Assumptions Used to Determine Net Periodic Benefit Cost for the Years Ended December 31 Discount rate 4.24% 4.49% 4.14% 3.92% 4.17% 3.95% Expected return on plan assets 6.55% 6.57% 6.73% N/A N/A N/A Rate of compensation increase 4.00% 4.00% 4.00% N/A N/A N/A Discount Rate Assumption. The discount rate reflects the current rate at which the pension obligations could be settled on the measurement date: December 31. The discount rate assumption used to calculate the present value of pension and postretirement benefit obligations reflects the rates available on high-quality, fixed-income debt instruments on December 31. In all periods, the bonds included in the models reflect anticipated investments that would be made to match the expected monthly benefit payments over time. The plans' projected cash flows were duration-matched to these models to develop an appropriate discount rate. Beginning in 2016, we refined the method used to determine the service and interest cost components of our net periodic benefit cost. Previously, the cost was determined using a single weighted-average discount rate derived from the yield curve. Under the refined method, known as the spot rate approach, we will use individual spot rates along the yield curve that correspond with the timing of each benefit payment. We believe this change provides a more precise measurement of service and interest costs by improving the correlation between projected cash outflows and corresponding spot rates on the yield curve. Asset Return Assumption. The expected return on plan assets reflects the expected long-term rates of return for the categories of investments currently held in the plans as well as anticipated returns for additional contributions made in the future. The expected long-term rate of return is adjusted when there are fundamental changes in expected returns on the plan investments. The weighted-average expected return on plan assets we will use in our calculation of 2018 net periodic pension benefit cost is 6.06%. Rate of Compensation Increase. The rate of compensation increase is determined by PCA based upon annual reviews. The compensation increase assumption is not applicable for all plans as many of our pension plans are frozen and not accruing benefits. Health Care Cost Trend Rate Assumptions. PCA assumed health care cost trend rates for its postretirement benefits plans were as follows: 2017 2016 2015 Health care cost trend rate assumed for next year 7.57% 7.35% 7.60% Rate to which the cost trend rate is assumed to decline (the ultimate trend rate) 4.44% 4.50% 4.50% Year that the rate reaches the ultimate trend rate 2027 2025 2024 Postretirement Health Care Plan Assumptions. For postretirement health care plan accounting, PCA reviews external data and its own historical trends for health care costs to determine the health care cost trend rate assumption. A one-percentage point change in assumed health care cost trend rates would have the following effects on the 2017 postretirement benefit obligation and the 2016 net post retirement benefit cost (dollars in millions): 1-Percentage Point Increase 1-Percentage Point Decrease Effect on postretirement benefit obligation $ 0.6 $ (0.6 ) Effect on net postretirement benefit cost 0.1 — Investment Policies and Strategies PCA has retained the services of professional advisors to oversee pension investments and provide recommendations regarding investment strategy. PCA’s overall strategy and related apportionments between equity and debt securities may change from time to time based on market conditions, external economic factors, and the funded status of the plans. The general investment objective for all of our plan assets is to optimize growth of the pension plan trust assets, while minimizing the risk of significant losses to enable the plans to satisfy their benefit payment obligations over time. The objectives take into account the long-term nature of the benefit obligations, the liquidity needs of the plans, and the expected risk/return trade-offs of the asset classes in which the plans may choose to invest. Assets of our pension plans were invested in the following classes of securities at December 31, 2017 and 2016: Percentage of Fair Value at December 31, 2017 2016 Fixed income securities 21 % 54 % International equity securities 6 % 23 % Domestic equity securities 9 % 21 % Real estate securities — 1 % Other 64 % 1 % As of December 31, 2017, the Company was in the process of consolidating the Boise pension plan assets with the PCA pension plans under one trustee. Due to this timing, 100% of the Boise pension plan assets were classified as Other (Cash) on December 31, 2017. Upon completion of the transfer on January 5, 2018, the pension plan assets were invested in the following classes of securities: Percentage of Fair Value at January 5, 2018 Fixed income securities 52 % International equity securities 28 % Domestic equity securities 20 % At December 31, 2017, the targeted investment allocations differed between the acquired Boise plans and PCA's historical plans based on funded status. At December 31, 2017, PCA's historical plans, which comprised $403.5 million of the fair value of plan assets, targeted 50% invested in equities, 49% invested in fixed income securities, and Investment securities, in general, are exposed to various risks, such as interest rate, credit, and overall market volatility risk, all of which are subject to change. Due to the level of risk associated with some investment securities, it is reasonably possible that changes in the values of investment securities will occur in the near term, and such changes could materially affect the reported amounts. Fair Value Measurements of Plan Assets The following tables set forth, by level within the fair value hierarchy, discussed in Note 2, Summary of Significant Accounting Policies, the pension plan assets, by major asset category, at fair value at December 31, 2017 and 2016 (dollars in millions): Fair Value Measurements at December 31, 2017 Asset Category Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Cash and short-term investments (a) $ 602.4 $ 5.7 $ — $ 608.1 Mutual funds: International equities 56.1 — — 56.1 Fixed income 95.4 — — 95.4 Common/collective trust funds (b): Domestic equities — 84.1 — 84.1 International equities — 5.6 — 5.6 Fixed income — 59.8 — 59.8 Corporate and government bonds: Fixed income 41.3 — — 41.3 Private equity securities (c) — — 4.2 4.2 Total securities at fair value $ 795.2 $ 155.2 $ 4.2 $ 954.6 Receivables and accrued expenses 0.2 Total fair value of plan assets $ 954.8 Fair Value Measurements at December 31, 2016 Asset Category Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Cash and short-term investments $ — $ 1.5 $ — $ 1.5 Mutual funds: Domestic equities 65.7 — — 65.7 International equities 68.7 — — 68.7 Real estate 9.6 — — 9.6 Fixed income 108.4 64.8 — 173.2 Common/collective trust funds (b): — Domestic equities — 107.9 — 107.9 International equities — 124.5 — 124.5 Fixed income — 271.6 — 271.6 Private equity securities (c) — — 5.7 5.7 Total securities at fair value $ 252.4 $ 570.3 $ 5.7 $ 828.4 Receivables and accrued expenses 2.0 Total fair value of plan assets $ 830.4 (a) Short-term investments and the Boise pension plan assets classified as cash as of December 31, 2017. The Boise pension plan assets were subsequently allocated to equities and fixed income securities on January 5, 2018 after consolidating with the PCA pension plan assets under one trustee. (b) Investments in common/collective trust funds valued using net asset values (NAV) provided by the administrator of the funds. The NAV is based on the value of the underlying assets owned by the fund, minus its liabilities, and then divided by the number of units outstanding. While the underlying assets are actively traded on an exchange, the funds are not. There are currently no redemption restrictions on these investments. There are certain funds with one-day redeemable notice. (c) Investments in this category are invested in the Pantheon Global Secondary Fund IV, LP. The fund specializes in investments in the private equity secondary market and occasionally directly in private companies to maximize capital growth. Fund investments are carried at fair value as determined quarterly using the market approach to estimate the fair value of private investments. The market approach utilizes prices and other relevant information generated by market transactions, type of security, size of the position, degree of liquidity, restrictions on the disposition, latest round of financing data, current financial position, and operating results, among other factors. In circumstances where fair values are not provided with respect to any of the company's fund investments, the investment advisor will seek to determine the fair value of such investments based on information provided by the general partners or managers of such funds or from other sources. Audited financial statements are provided by fund management annually. Notwithstanding the above, the variety of valuation bases adopted and quality of management data of the ultimate underlying investee companies means that there are inherent difficulties in determining the value of the investments. Amounts realized on the sale of these investments may differ from the calculated values. Boise had originally committed to a $15.0 million investment, with $5.0 million of the commitment unfunded at December 31, 2017. The following table sets forth a summary of changes in the fair value of the pension plans' Level 3 assets for the year ended December 31, 2017 (dollars in millions): 2017 Balance, beginning of year $ 5.7 Acquisitions — Purchases — Sales (1.5 ) Unrealized gain — Balance, end of year $ 4.2 Funding and Cash Flows PCA makes pension plan contributions that are sufficient to fund its actuarially determined costs, generally equal to the minimum amounts required by the Employee Retirement Income Security Act (ERISA). From time to time, PCA may make discretionary contributions based on the funded status of the plans, tax deductibility, income from operations, and other factors. In 2017, we made contributions of $42.1 million to our qualified pension plans. In 2016, we made contributions of $57.1 million to our qualified pension plans. In 2015, we did not make contributions to our qualified pension plans. We expect to contribute at least the estimated required minimum contributions to our qualified pension plans of approximately $4.6 million in 2018. The following are estimated benefit payments to be paid to current plan participants by year (dollars in millions). Qualified pension benefit payments are paid from plan assets, while nonqualified pension benefit payments are paid by the Company. Pension Plans Postretirement Plans 2018 $ 45.4 $ 1.0 2019 49.3 1.0 2020 53.2 1.0 2021 57.0 0.9 2022 - 2025 407.9 5.4 Defined Contribution Plans Some of our employees participate in contributory defined contribution savings plans, available to most of our salaried and hourly employees. The defined contribution plans permit participants to make contributions by salary reduction pursuant to Section 401(k) of the Code. PCA made employer-matching contributions of $42.8 million, $40.4 million, and $37.9 million in 2017, 2016, and 2015, respectively. In 2015, Company matching contributions to certain full-time salaried employees were made in company stock, through our Employee Stock Ownership Plan (ESOP). All other matching contributions were in cash. Beginning in 2016, all company-matching contributions to all employees were made in cash. We expense employer matching contributions and charge dividends on shares held by the ESOP to retained earnings. Shares of company stock held by the ESOP are included in basic shares for earnings-per-share computations. At December 31, 2017 and 2016, the ESOP held 1.8 million and 2.2 million shares of Company stock, respectively. Certain salaried and hourly employees that are not participating in a PCA sponsored defined benefit pension plan receive a service-related company retirement contribution to their defined contribution plan account in addition to any employer matching contribution. This contribution increases with years of service and ranges from 3% to 5% of base pay. We contributed $22.4 million, $14.9 million, and $12.4 million for this retirement contribution during the years ended December 31, 2017, 2016, and 2015, respectively. Deferred Compensation Plans Key managers can elect to participate in a deferred compensation plan. The deferred compensation plan is unfunded; therefore, benefits are paid from our general assets. At December 31, 2017 and 2016, we had $13.6 million and $13.7 million, respectively, of liabilities attributable to participation in our deferred compensation plan on our Consolidated Balance Sheets.

Asset Retirement Obligations

Asset Retirement Obligations	12 Months Ended
	Dec. 31, 2017
Asset Retirement Obligation [Abstract]
Asset Retirement Obligations	11. Asset Retirement Obligations Our asset retirement obligations relate predominantly to landfill closure, wastewater treatment pond dredging, closed-site monitoring costs, and certain leasehold improvements. In accordance with ASC 410, “Asset Retirement and Environmental Obligations , The following table describes changes to the asset retirement obligation liability (dollars in millions): Year Ended December 31 2017 2016 Asset retirement obligation at beginning of period $ 28.0 $ 26.2 Accretion expense 1.3 2.3 Payments (2.3 ) (2.2 ) Revisions in estimated cash flows 7.9 1.2 Liabilities incurred 0.2 0.5 Asset retirement obligation at end of period $ 35.1 $ 28.0 We have additional asset retirement obligations with indeterminate settlement dates. The fair value of these asset retirement obligations cannot be estimated due to the lack of sufficient information to estimate the settlement dates of the obligations. These asset retirement obligations include, for example, (i) removal and disposal of potentially hazardous materials related to equipment and/or an operating facility if the equipment and/or facilities were to undergo major maintenance, renovation, or demolition and (ii) storage sites or owned facilities for which removal and/or disposal of chemicals and other related materials are required if the operating facility is closed. We will recognize a liability in the period in which sufficient information becomes available to reasonably estimate the fair value of these obligations.

Share-Based Compensation

Share-Based Compensation	12 Months Ended
	Dec. 31, 2017
Share Based Compensation [Abstract]
Share-Based Compensation	12. Share-Based Compensation The Company has a long-term equity incentive plan, which allows for grants of stock options, stock appreciation rights, restricted stock, and performance awards to directors, officers, and employees, as well as others who engage in services for PCA. The plan, as amended, terminates May 1, 2023, and authorizes 10.6 million shares of common stock for grant over the life of the plan. As of December 31, 2017, 1.0 million shares remained available for future issuance under the plan. Forfeitures are added back to the pool of shares of common stock available to be granted at a future date. Restricted Stock Restricted stock awards granted to officers and employees generally vest at the end of a four-year period, and restricted stock awards granted to directors vest immediately. The fair value of restricted stock is determined based on the closing price of the Company’s stock on the grant date. A summary of the Company’s restricted stock activity follows: 2017 2016 2015 Shares Weighted Average Grant- Date Fair Value Shares Weighted Average Grant- Date Fair Value Shares Weighted Average Grant- Date Fair Value Restricted stock at January 1 786,079 $ 63.44 1,007,794 $ 49.47 1,184,299 $ 41.71 Granted 173,199 107.57 242,835 67.48 218,957 65.16 Vested (a) (213,992 ) 51.37 (443,627 ) 34.11 (389,481 ) 32.77 Forfeitures (5,554 ) 69.03 (20,923 ) 59.63 (5,981 ) 66.42 Restricted stock at December 31 739,732 $ 77.23 786,079 $ 63.44 1,007,794 $ 49.47 (a) The total fair value of awards upon vesting for the years ended December 31, 2017, 2016, and 2015 was $23.3 million, . Performance Units Performance award units granted to certain key employees vest four years after the grant date based on the achievement of defined performance rankings compared to a peer group. The performance units are paid out entirely in shares of the Company’s common stock. The awards are valued at the closing price of the Company’s stock on the grant date and expensed over the requisite service period based on the most probable number of awards expected to vest. 2017 2016 2015 Units Weighted Average Grant- Date Fair Value Units Weighted Average Grant- Date Fair Value Units Weighted Average Grant- Date Fair Value Performance units at January 1 232,088 $ 62.68 175,675 $ 59.94 127,489 $ 58.25 Granted 61,861 108.19 77,017 67.57 53,102 65.04 Vested (a) (67,391 ) 56.08 (20,604 ) 57.58 (4,916 ) 71.19 Performance units at December 31 226,558 $ 77.07 232,088 $ 62.68 175,675 $ 59.94 (a) The total fair value of awards upon vesting for the years ended December 31, 2017, 2016, and 2015 was $7.5 million, $1.1 million, and $0.3 million, respectively. Upon vesting of the awards in 2016 and 2015, PCA issued 21,111 and 5,090 shares, which included 507 and 174 shares, respectively, for dividends accrued during the vesting period. Compensation Expense Our share-based compensation expense is recorded in “Selling, general, and administrative expenses.” Compensation expense for share-based awards recognized in the Consolidated Statements of Income, net of forfeitures was as follows (dollars in millions): Year Ended December 31 2017 2016 2015 Restricted stock $ 15.0 $ 15.8 $ 15.2 Performance units 5.6 3.9 3.0 Impact on income before income taxes 20.6 19.7 18.2 Income tax benefit (7.9 ) (7.7 ) (7.1 ) Impact on net income $ 12.7 $ 12.0 $ 11.1 The fair value of restricted stock and performance units is determined based on the closing price of the Company’s common stock on the grant date. As PCA’s Board of Directors has the ability to accelerate vesting of share-based awards upon an employee’s retirement, the Company accelerates the recognition of compensation expense for certain employees approaching normal retirement age. The unrecognized compensation expense for all share-based awards was as follows (dollars in millions): December 31, 2017 Unrecognized Compensation Expense Remaining Weighted Average Recognition Period (in years) Restricted stock $ 30.6 2.5 Performance units 9.8 2.8 Total unrecognized share-based compensation expense $ 40.4 2.6 We evaluate share-based compensation expense on a quarterly basis based on our estimate of expected forfeitures, review of recent forfeiture activity, and expected future turnover. We recognize the effect of adjusting the forfeiture rate for all expense amortization in the period that we change the forfeiture estimate. The effect of forfeiture adjustments was insignificant in all periods presented.

Derivative Instruments and Hedg

Derivative Instruments and Hedging Activities	12 Months Ended
	Dec. 31, 2017
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Derivative Instruments and Hedging Activities	13. Derivative Instruments and Hedging Activities Hedging Strategy When appropriate, we use derivatives as a risk management tool to mitigate the potential impact of certain market risks. The primary risks managed by using derivative financial instruments are interest rate risks. We do not enter into derivative financial instruments for trading or speculative purposes. Interest Rate Risk The Company has used treasury lock derivative instruments to manage interest costs and the risk associated with changing interest rates. In connection with contemplated issuances of ten-year debt securities, PCA entered into interest rate protection agreements with counterparties in 2008, 2010, and 2011 to protect against increases in the ten-year U.S. Treasury Note rate. These treasury rates served as references in determining the interest rates applicable to the debt securities the Company issued in March 2008, February 2011, and June 2012. As a result of changes in the interest rates on those treasury securities between the time PCA entered into the derivative agreements and the time PCA priced and issued the debt securities, the Company: (1) made a payment of $4.4 million to the counterparty upon settlement of the 2008 interest rate protection agreement on March 25, 2008; (2) received a payment of $9.9 million from the counterparties upon settlement of the 2010 interest rate protection agreements on February 4, 2011; and (3) made a payment of $65.5 million to the counterparty upon settlement of the 2011 interest rate protection agreement on June 26, 2012. The Company recorded the effective portion of the settlements in AOCI, and these amounts are being amortized over the terms of the respective notes. Derivative Instruments The impact of derivative instruments on the consolidated statements of income and accumulated OCI was as follows (dollars in millions): Net Loss Recognized in Accumulated OCI (Effective Portion) December 31, 2017 2016 Treasury locks, net of tax $ (14.2 ) $ (17.7 ) Loss Reclassified from Accumulated OCI into Income (Effective Portion) Year Ended December 31, 2017 2016 2015 Amortization of treasury locks (included in interest expense, net) $ (5.7 ) $ (5.7 ) $ (5.7 ) The net amount of settlement gains or losses on derivative instruments included in accumulated OCI to be amortized over the next 12 months is a net loss of $5.3 million ($3.3 million after-tax).

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2017
Equity [Abstract]
Stockholders' Equity	14. Stockholders' Equity Dividends During the year ended December 31, 2017, we paid $237.6 million of dividends to shareholders. On December 14, 2017 PCA's Board of Directors approved a regular quarterly cash dividend of $0.63 per share of common stock, which was paid on January 12, 2018 to shareholders of record as of December 26, 2017. The dividend payment was $59.4 million. On August 31, 2016, PCA announced an increase of its quarterly cash dividend on its common stock from an annual payout of $2.20 per share to an annual payout of $2.52 per share. The first quarterly dividend of $0.63 per share was paid on October 14, 2016 to shareholders of record as of September 15, 2016. Share Repurchase Program On February 25, 2016, PCA announced that its Board of Directors authorized the repurchase of $200.0 million of the Company's outstanding common stock. Repurchases may be made from time to time in open market or privately negotiated transactions in accordance with applicable securities regulations. The timing and amount of repurchases will be determined by the Company in its discretion based on factors such as PCA’s stock price and market and business conditions. The Company did not repurchase any shares of its common stock under this authority during the twelve months ended December 31, 2017. Share repurchase activity in 2015 and 2016 follows (in millions, except share and per share amounts). Shares Weighted Average Price Per Share Total 2015 2,326,493 $ 66.50 $ 154.7 2016 1,987,187 50.49 100.3 All shares repurchased have been retired. At December 31, 2017, $193.0 million Accumulated Other Comprehensive Income (Loss) Changes in AOCI, net of taxes, by component follows (dollars in millions). Amounts in parentheses indicate losses. Foreign Currency Translation Adjustments Unrealized Loss On Treasury Locks, Net Unrealized Loss on Foreign Exchange Contracts Unfunded Employee Benefit Obligations Total Balance at December 31, 2016 $ (0.1 ) $ (17.7 ) $ (0.3 ) $ (121.5 ) $ (139.6 ) Other comprehensive income before reclassifications — — — (28.8 ) (28.8 ) Amounts reclassified from AOCI (0.2 ) 3.5 — 8.2 11.5 Net current-period other comprehensive income (0.2 ) 3.5 — (20.6 ) (17.3 ) Balance at December 31, 2017 $ (0.3 ) $ (14.2 ) $ (0.3 ) $ (142.1 ) $ (156.9 ) The following table presents information about reclassifications out of AOCI (dollars in millions). Amounts in parentheses indicate expenses in the Consolidated Statements of Income. Amounts Reclassified from AOCI Year Ended December 31, Details about AOCI Components 2017 2016 Unrealized loss on treasury locks, net (a) $ (5.7 ) $ (5.7 ) 2.2 2.2 Tax benefit $ (3.5 ) $ (3.5 ) Net of tax Unfunded employee benefit obligations (b) Amortization of prior service costs $ (5.6 ) $ (5.5 ) Amortization of actuarial gains / (losses) (7.5 ) (5.4 ) (13.1 ) (10.9 ) Total before tax 4.9 4.2 Tax benefit $ (8.2 ) $ (6.7 ) Net of tax (a) This AOCI component is included in interest expense, net. Amount relates to the amortization of the effective portion of treasury lock derivative instruments recorded in AOCI. The net amount of settlement gains or losses on derivative instruments included in AOCI to be amortized over the next 12 months is a net loss of $5.3 million ($3.3 million after-tax). For a discussion of treasury lock derivative instrument activity, see Note 13, Derivative Instruments and Hedging Activities, for additional information. (b) These AOCI components are included in the computation of net pension and postretirement benefit costs. See Note 10, Employee Benefit Plans and Other Postretirement Benefits, for additional information.

Concentrations of Risk

Concentrations of Risk	12 Months Ended
	Dec. 31, 2017
Risks And Uncertainties [Abstract]
Concentration of Risk	15. Concentrations of Risk Our Paper segment has had a long-standing commercial and contractual relationship with Office Depot, our largest customer in the paper business. This relationship exposes us to a significant concentration of business and financial risk. Our sales to Office Depot represented 7% and 8% of our total company sales for 2017 and 2016, respectively, and about 43% and 42% of our Paper segment sales revenue for those periods, respectively. At December 31, 2017 and 2016, we had $33.3 million and $31.8 million of accounts receivable due from Office Depot, respectively, which represents 4% and 5% of our total Company receivables, respectively. In 2017, sales to Office Depot represented 43% of our Paper segment sales. If these sales are reduced, we would need to find new customers. We may not be able to fully replace any lost sales, and any new sales may be at lower prices or higher costs. Any significant deterioration in the financial condition of Office Depot affecting its ability to pay or any other change that affects its willingness to purchase our products will harm our business and results of operations. Labor At December 31, 2017, we had approximately 14,600 employees and approximately 45%

Transactions With Related Parti

Transactions With Related Parties	12 Months Ended
	Dec. 31, 2017
Related Party Transactions [Abstract]
Transactions With Related Parties	16. Transactions With Related Parties Louisiana Timber Procurement Company, L.L.C. (LTP) is a variable-interest entity that is 50% owned by PCA and 50% owned by Boise Cascade Company (Boise Cascade). LTP procures sawtimber, pulpwood, residual chips, and other residual wood fiber to meet the wood and fiber requirements of PCA and Boise Cascade in Louisiana. PCA is the primary beneficiary of LTP and has the power to direct the activities that most significantly affect the economic performance of LTP. Therefore, we consolidate 100% of LTP in our financial statements in our Corporate and Other segment. The carrying amounts of LTP's assets and liabilities (which relate primarily to non-inventory working capital items) on our Consolidated Balance Sheets were both $3.0 million at December 31, 2017 and $5.0 million at December 31, 2016. For 2017, 2016, and 2015, we recorded $86.4 million, $86.9 million, and $88.8 million, respectively, of LTP sales to Boise Cascade in “Net Sales” in the Consolidated Statements of Income and approximately the same amount of expenses in “Cost of Sales”. For 2017, 2016, and 2015, fiber purchases from related parties were $16.6 million ,

Segment Information

Segment Information	12 Months Ended
	Dec. 31, 2017
Segment Reporting [Abstract]
Segment Information	17. Segment Information We report our business in three reportable segments: Packaging, Paper, and Corporate and Other. These segments represent distinct businesses that are managed separately because of differing products and services. Each of these businesses require distinct operating and marketing strategies. Packaging. We manufacture and sell a wide variety of corrugated packaging products, including conventional shipping containers used to protect and transport manufactured goods, multi-color boxes and displays with strong visual appeal that help to merchandise the packaged product in retail locations. In addition, we are a large producer of packaging for meat, fresh fruit and vegetables, processed food, beverages, and other industrial and consumer products. Paper. We manufacture and sell a range of white papers, including communication-based papers, and pressure sensitive papers. Our white papers can be manufactured as either commodity papers or specialty papers with specialized or custom features, such as colors, coatings, high brightness, or recycled content. Sales for market pulp decreased in 2016 as we ceased softwood market pulp operations at our Wallula, Washington mill with the permanent shutdown of the No.1 machine. Corporate and Other. Our Corporate and Other segment includes corporate support staff services and related assets and liabilities, and foreign exchange gains and losses. This segment also includes transportation assets, such as rail cars and trucks, which we use to transport our products from some of our manufacturing sites and assets related to LTP. See Note 16, Transactions with Related Parties, for more information related to LTP. Sales in this segment relate primarily to LTP and our rail and truck business. We provide transportation services not only to our own facilities but also, on a limited basis, to third parties when geographic proximity and logistics are favorable. Rail cars and trucks are generally leased. Each segments' profits and losses are measured on operating profits before interest expense and interest income. For many of these allocated expenses, the related assets and liabilities remain in the Corporate and Other segment. Segment sales to external customers by product line were as follows (dollars in millions): Year Ended December 31, 2017 2016 2015 Packaging sales Packaging sales $ 5,312.3 $ 4,584.8 $ 4,477.3 Paper White papers 1,051.8 1,065.8 1,089.6 Market pulp — 28.1 53.5 1,051.8 1,093.9 1,143.1 Corporate and Other 80.8 100.3 121.3 $ 6,444.9 $ 5,779.0 $ 5,741.7 Sales to foreign unaffiliated customers during the years ended December 31, 2017, 2016, and 2015 were An analysis of operations by reportable segment is as follows (dollars in millions): Sales, net Operating Depreciation, Capital Year Ended December 31, 2017 Trade Inter- segment Total Income (Loss) Amortization, and Depletion Expenditures (k) Assets Packaging $ 5,288.6 $ 23.7 $ 5,312.3 $ 943.7 (a) $ 317.5 $ 305.1 $ 4,933.6 Paper 1,051.8 — 1,051.8 61.5 (b) 67.6 22.6 945.2 Corporate and Other 104.5 124.7 229.2 (74.0 ) (c) 6.3 15.3 318.7 Intersegment eliminations — (148.4 ) (148.4 ) — — — — $ 6,444.9 $ — $ 6,444.9 931.2 $ 391.4 $ 343.0 $ 6,197.5 Interest expense (102.6 ) (j) Income before taxes $ 828.6 Sales, net Operating Depreciation, Capital Year Ended December 31, 2016 Trade Inter- segment Total Income (Loss) Amortization, and Depletion Expenditures (k) Assets Packaging $ 4,577.4 $ 7.4 $ 4,584.8 $ 711.0 (d) $ 293.3 $ 239.9 $ 4,530.5 Paper 1,093.9 — 1,093.9 138.1 (e) 59.6 31.6 946.2 Corporate and Other 107.7 139.2 246.9 (68.9 ) (f) 5.1 2.8 300.3 Intersegment eliminations — (146.6 ) (146.6 ) — — — — $ 5,779.0 $ — $ 5,779.0 780.3 $ 358.0 $ 274.3 $ 5,777.0 Interest expense (91.8 ) Income before taxes $ 688.5 Sales, net Operating Depreciation, Capital Year Ended December 31, 2015 Trade Inter- segment Total Income (Loss) Amortization, and Depletion Expenditures (k) Assets Packaging $ 4,474.1 $ 3.2 $ 4,477.3 $ 714.9 (g) $ 297.3 $ 250.3 $ 4,027.9 Paper 1,143.1 — 1,143.1 112.5 (h) 54.9 58.5 976.5 Corporate and Other 124.5 133.8 258.3 (77.4 ) (i) 4.3 5.7 267.9 Intersegment eliminations — (137.0 ) (137.0 ) — — — — $ 5,741.7 $ — $ 5,741.7 750.0 $ 356.5 $ 314.5 $ 5,272.3 Interest expense (85.5 ) Income before taxes $ 664.5 (a) Includes the following: o $7.2 million of income, net, primarily related to the sale of land corresponding to the closure of a corrugated products facility, partially offset by closure costs related to corrugated products facilities, and a lump sum settlement of a multiemployer pension plan withdrawal liability for one of our corrugated products facilities. o $1.7 million of charges related to the Sacramento Container acquisition and integration costs related to other recent acquisitions. o $2.0 million gain related to the expiration of a repurchase option corresponding to timberland previously sold. o $1.6 million of income related to a working capital adjustment from the April 2015 sale of our Hexacomb corrugated manufacturing operations in Europe and Mexico. o $5.0 million of costs for the property damage and business interruption insurance deductible corresponding to the February 2017 explosion at our DeRidder, Louisiana mill. (b) Includes $33.4 million of charges related to our determination to discontinue production of uncoated free sheet and coated one-side grades at the Wallula, Washington mill in the second quarter of 2018 and convert the No. 3 paper machine to a high-performance 100% virgin kraft linerboard machine and $0.4 million of charges related to the closure costs of a paper administration facility. (c) Includes $1.0 million of charges related to the closure costs of a corporate administration facility and $0.7 million of income related to a working capital adjustment from the April 2015 sale of our Hexacomb corrugated manufacturing operations in Europe and Mexico. (d) Includes $10.2 million of closure costs related to corrugated product facilities and $4.2 million of acquisition-related costs for the TimBar Corporation and Columbus Container acquisitions. (e) Includes $2.7 million of costs related to ceased softwood market pulp operations at our Wallula, Washington mill and the permanent shut down of the No.1 machine and $1.7 million of closure costs related to a paper products facility. (f) Includes $0.3 million of acquisition-related costs related to the TimBar Corporation acquisition. (g) Includes net charges of $2.0 million primarily related to restructuring activities at our mill in DeRidder, Louisiana and $4.1 million of Boise acquisition integration-related and other costs. (h) In September 2015, we sold the remaining land, buildings, and equipment at our paper mill site in St. Helens, Oregon where we ceased paper production in December 2012. We recorded a $6.7 million gain on the sale. ( i ) Includes $9.3 million of Boise acquisition integration-related and other costs. These costs primarily relate to professional fees, severance, retention, relocation, travel, and other integration-related costs. (j) Includes $1.8 million of expense related to the write-off of deferred debt issuance costs in connection with the December 2017 debt refinancing. (k) Includes “Additions to property, plant, and equipment” and excludes cash used for “Acquisitions of businesses, net of cash acquired” as reported on our Consolidated Statements of Cash Flows.

Commitments, Guarantees, Indemn

Commitments, Guarantees, Indemnifications, and Legal Proceedings	12 Months Ended
	Dec. 31, 2017
Commitments And Contingencies Disclosure [Abstract]
Commitments, Guarantees, Indemnifications, and Legal Proceedings	18. Commitments, Guarantees, Indemnifications, and Legal Proceedings We have financial commitments and obligations that arise in the ordinary course of our business. These include long-term debt (discussed in Note 9, Debt), capital commitments, lease obligations, purchase commitments for goods and services, and legal proceedings (discussed below). Capital Commitments The Company had capital commitments of approximately $281.3 million and $94.7 million as of December 31, 2017 and 2016, respectively, in connection with the expansion and replacement of existing facilities and equipment. Lease Obligations PCA leases space for certain of its facilities, cutting rights to approximately 75,000 acres of timberland, land for a fiber farm, and equipment, primarily vehicles and rolling stock. Remaining lease terms average 14 years and may contain renewal options or escalation clauses. Substantially all lease agreements have fixed payment terms based on the passage of time. Some lease agreements provide us with the option to purchase the leased property. Additionally, some agreements contain renewal options averaging approximately six 2018 $ 63.8 2019 54.0 2020 41.1 2021 29.6 2022 19.1 Thereafter 56.2 Total $ 263.8 Total lease expense, including base rent on all leases and executory costs, such as insurance, taxes, and maintenance, for the years ended December 31, 2017, 2016, and 2015, was $100.6 million, $88.3 million and $87.9 million, respectively. These costs are included in “Cost of sales” and “Selling, general, and administrative expenses” in our Consolidated Statements of Income. We had no sublease rental income for the year ended December 31, 2017 and an insignificant amount of sublease rental income in the years ended December 31, 2016 and 2015. PCA was obligated under capital leases covering buildings and machinery and equipment in the amount of $20.3 million and $21.6 million at December 31, 2017 and 2016, respectively. Assets held under capital lease obligations were included in property, plant, and equipment as follows (dollars in millions): Year Ended December 31 2017 2016 Buildings $ 0.3 $ 0.3 Machinery and equipment 28.5 28.5 Total 28.8 28.8 Less accumulated amortization (15.2 ) (13.7 ) Total $ 13.6 $ 15.1 Amortization of assets under capital lease obligations is included in depreciation expense. The future minimum payments under capitalized leases at December 31, 2017 were as follows (dollars in millions): 2018 $ 2.7 2019 2.7 2020 2.7 2021 2.7 2022 2.7 Thereafter 15.0 Total minimum capital lease payments 28.5 Less amounts representing interest (8.2 ) Present value of net minimum capital lease payments 20.3 Less current maturities of capital lease obligations (1.3 ) Total long-term capital lease obligations $ 19.0 Interest expense related to capital lease obligations for the years ended December 31, 2017, 2016, and 2015 was $1.4 million, $1.5 million, and $1.6 million, respectively. Purchase Commitments In the table below, we set forth our enforceable and legally binding purchase obligations as of December 31, 2017. Some of the amounts are based on management's estimates and assumptions about these obligations, including their duration, the possibility of renewal, anticipated actions by third parties, and other factors. Because these estimates and assumptions are necessarily subjective, our actual payments may vary from those reflected in the table. Purchase orders made in the ordinary course of business are excluded below. Any amounts for which we are liable under purchase orders are reflected on the Consolidated Balance Sheets as accounts payable and accrued liabilities. These obligations relate to various purchase agreements for items such as minimum amounts of energy and fiber purchases over periods ranging from one year to 22 years. Total purchase commitments were as follows (dollars in millions): 2018 $ 79.8 2019 54.4 2020 45.6 2021 43.0 2022 42.5 Thereafter 159.0 Total $ 424.3 The Company purchased a total of $339.1 million, $362.0 million, and $299.6 million during the years ended December 31, 2017, 2016, and 2015, respectively, under these purchase agreements. Environmental Liabilities The potential costs for various environmental matters are uncertain due to such factors as the unknown magnitude of possible cleanup costs, the complexity and evolving nature of governmental laws and regulations and their interpretations, and the timing, varying costs and effectiveness of alternative cleanup technologies. From 2006 through 2017, there were no significant environmental remediation costs at PCA's mills and corrugated plants. At December 31, 2017, the Company had $31.5 million of environmental-related reserves recorded on its Consolidated Balance Sheet. Of the $31.5 million, approximately $24.0 million related to environmental-related asset retirement obligations discussed in Note 11, Asset Retirement Obligations, and $7.5 million related to our estimate of other environmental contingencies. The Company recorded $4.0 million in “Accrued liabilities” and $27.5 million in “Other long-term liabilities” on the Consolidated Balance Sheet. Liabilities recorded for environmental contingencies are estimates of the probable costs based upon available information and assumptions. Because of these uncertainties, PCA’s estimates may change. The Company believes that it is not reasonably possible that future environmental expenditures for remediation costs and asset retirement obligations above the $31.5 million accrued as of December 31, 2017, will have a material impact on its financial condition, results of operations, or cash flows. Guarantees and Indemnifications We provide guarantees, indemnifications, and other assurances to third parties in the normal course of our business. These include tort indemnifications, environmental assurances, and representations and warranties in commercial agreements. At December 31, 2017, we are not aware of any material liabilities arising from any guarantee, indemnification, or financial assurance we have provided. If we determined such a liability was probable and subject to reasonable determination, we would accrue for it at that time. DeRidder Mill Incident On February 8, 2017, a tank located in the pulp mill at the Company's DeRidder, Louisiana facility exploded, resulting in three contractor fatalities and other injuries. The Company has been served with multiple lawsuits and is on notice of additional claims. The Company maintains liability insurance subject to a $1.0 million deductible; however, the incident remains under investigation and the lawsuits are in the early stages. Accordingly, the Company is unable to estimate a range of reasonable possible losses at this time. The Company has also incurred property damage and business interruption losses and has claimed these losses, subject to a $5.0 million deductible, under its property damage and business interruption insurance policy. As of December 31, 2017, the Company finalized the claim with the insurance carrier for $17.0 million, net of the deductible, which was recorded in “Other expense, net.” Payment for the receivable was received in January 2018. The Company is cooperating with investigations from the U.S. Occupational Health and Safety Administration, the U.S. Chemical Safety Board and the Environmental Protection Agency relating to the incident. Legal proceedings We are also a party to various legal actions arising in the ordinary course of our business. These legal actions include commercial liability claims, premises liability claims, and employment-related claims, among others. As of the date of this filing, we believe it is not reasonably possible that any of the legal actions against us will, either individually or in the aggregate, have a material adverse effect on our financial condition, results of operations, or cash flows.

Quarterly Results of Operations

Quarterly Results of Operations (Unaudited)	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Quarterly Results of Operations (Unaudited)	19. Quarterly Results of Operations (unaudited, dollars in millions, except per-share and stock price information) 2017: First (a) Second (b) Third (c) Fourth (d) Total Net sales $ 1,536.5 $ 1,584.0 $ 1,640.1 $ 1,684.3 $ 6,444.9 Gross profit 338.5 364.6 397.3 371.7 1,472.2 Income from operations 203.1 233.8 242.3 252.0 931.2 Net income 117.4 143.2 139.1 268.9 668.6 Basic earnings per share 1.25 1.52 1.47 2.85 7.09 Diluted earnings per share 1.24 1.52 1.47 2.84 7.07 Stock price - high 96.87 113.52 119.43 121.38 121.38 Stock price - low 84.01 89.73 105.81 108.49 84.01 2016: First (e) Second (f) Third (g) Fourth (h) Total Net sales $ 1,401.0 $ 1,417.4 $ 1,484.0 $ 1,476.6 $ 5,779.0 Gross profit 299.0 320.1 329.5 327.1 $ 1,275.7 Income from operations 180.8 200.2 206.4 192.9 780.3 Net income 103.7 115.9 119.4 110.6 449.6 Basic earnings per share 1.09 1.23 1.27 1.17 4.76 Diluted earnings per share 1.09 1.23 1.26 1.17 4.75 Stock price - high 62.67 71.31 82.77 88.41 88.41 Stock price - low 44.32 58.44 65.12 78.03 44.32 Note: The sum of the quarters may not equal the total of the respective year's earnings per share on either a basic or diluted basis due to changes in the weighted average shares outstanding throughout the year. (a) Includes $0.6 million of charges related to the closure of corrugated products facilities and lump sum settlement of a multiemployer pension plan withdrawal liability for one of corrugated products facilities ($0.4 million after-tax or $0.1 per diluted share) and $0.2 million of charges related to TimBar Corporation and Columbus Container integration costs ($0.1 million after-tax or $0.0 per diluted share). Also includes $5.0 million of costs for the property damage and business interruption insurance deductible corresponding to the February 2017 explosion at our DeRidder, Louisiana mill ($3.1 million after-tax or $0.03 per diluted share) and $2.3 million of income related to a working capital adjustment from the April 2015 sale of our Hexacomb corrugated manufacturing operations in Europe and Mexico ($1.4 million after-tax or $0.01 per diluted share). (b) Includes $0.3 million of charges related to the closure of corrugated products facilities ($0.3 million after-tax or $0.0 per diluted share) and $0.2 million of charges related to TimBar Corporation and Columbus Container integration costs ($0.1 after-tax or $0.0 per diluted share). (c) Includes $0.9 million of charges related to the closure of corrugated products facilities, a paper administration facility, and a lump sum settlement of a multiemployer pension plan withdrawal liability for one of our corrugated products facilities ($0.6 million after-tax or $0.01 per diluted share) and $0.5 million of charges related to the Sacramento Container acquisition and integration costs related to other recent acquisitions ($0.3 million after-tax or $0.0 per diluted share). Also includes $25.3 million of charges related to our determination to discontinue production of uncoated free sheet and coated one-side grades at the Wallula, Washington mill in the second quarter of 2018 and convert the No. 3 paper machine to a high-performance 100% virgin kraft linerboard machine ($15.5 million after-tax or $0.16 per diluted share) and $3.3 million of tax expense for the change in value of deferred taxes as a result of an internal legal entity consolidation that will simplify future operating activities ($0.04 per diluted share). (d) Includes $7.6 million of income primarily related to the sale of land corresponding to the closure of a corrugated products facility, partially offset by closure costs related to corrugated products facilities, a paper administration facility, and a corporate administration facility ($4.7 million after-tax or $0.05 per diluted share) and $0.9 million of charges related to the Sacramento Container acquisition and integration costs related to other recent acquisitions ($0.5 million after-tax or $0.01 per diluted share), and $8.0 million of charges related to our determination to discontinue production of uncoated free sheet and coated one-side grades at the Wallula, Washington mill in the second quarter of 2018 and convert the No. 3 paper machine to a high-performance 100% virgin kraft linerboard machine ($4.6 million after-tax or $0.05 per diluted share). Also includes $1.8 million of expense related to the write-off of deferred debt issuance costs in connection with the December 2017 debt refinancing ($1.1 million after-tax or $0.01 per diluted share), $2.0 million gain related to the expiration of a repurchase option corresponding to timberland previously sold ($1.2 million after-tax or 0.01 per diluted share), and $122.1 million of estimated income tax benefit related to the enactment in December 2017 of the Tax Cuts and Jobs Act (H.R.1) primarily for the re-measurement of our net deferred tax liability as a result of the reduction in the U.S. corporate income tax rate ($1.29 per diluted share). (e) Includes $2.8 million of charges related to the closure of a corrugated products facility and a paper products facility ($1.9 million after-tax or $0.02 per diluted share). (f) Includes $2.6 million of charges related to the closure of corrugated products facilities, a paper products facility, and a lump sum settlement of a multiemployer pension plan withdrawal liability for one of our corrugated products facilities ($1.6 million after-tax or $0.02 per diluted share) and $0.3 million of charges related to the TimBar Corporation acquisition and integration ($0.2 million after-tax or $0.0 per diluted share). (g) Includes $2.0 million of charges related to the closure of a corrugated products facility and a paper products facility ($1.4 million after-tax or $0.02 per diluted share) and $2.9 million of charges related to the TimBar Corporation and Columbus Container acquisitions and integration ($1.9 million after-tax or $0.02 per diluted share). (h) Includes $4.5 million of charges related to the closure of a corrugated products facility and a paper products facility ($2.9 million after-tax or $0.03 per diluted share), $2.7 million of costs related to ceased production of softwood market pulp operations at our Wallula, Washington mill and the permanent shutdown of the No. 1 machine ($1.8 million after-tax or $0.02 per diluted share), and $1.2 million of charges related to the TimBar Corporation and Columbus Container acquisitions and integration ($0.8 million after-tax or $0.01 per diluted share).

Summary of Significant Accoun27

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions about future events. These estimates and the underlying assumptions affect the amounts of assets and liabilities reported, disclosures about contingent assets and liabilities, and reported amounts of revenues and expenses. These estimates and assumptions are based on management's best estimates and judgment. Management evaluates its estimates and assumptions on an ongoing basis using historical experience and other factors, including the current economic environment. We adjust such estimates and assumptions when facts and circumstances dictate. As future events and their effects cannot be determined with precision, actual results could differ significantly from these estimates. Changes in these estimates will be reflected in the consolidated financial statements in future periods.
Revenue Recognition	Revenue Recognition We recognize revenue when the following criteria are met: persuasive evidence of an agreement exists, the customer takes title and assumes risks and rewards of ownership or services have been rendered, our price to the buyer is fixed or determinable, and collectability is reasonably assured. The timing of revenue recognition is dependent on transfer of title, which is normally either on exit from our plants (i.e., shipping point) or on arrival at customer’s location (i.e., destination point). Shipping and handling billings to a customer are included in net sales. Shipping and handling costs, such as freight to our customers' destinations, are included in cost of sales. We present taxes collected from customers and remitted to governmental authorities on a net basis in our Consolidated Statements of Income.
Planned Major Maintenance Costs	Planned Major Maintenance Costs The Company accounts for its planned major maintenance activities in accordance with ASC 360, Property, Plant, and Equipment
Share-Based Compensation	Share-Based Compensation We recognize compensation expense for awards granted under the PCA long-term equity incentive plans based on the fair value on the grant date. We recognize the cost of the equity awards expected to vest over the period the awards vest. See Note 12, Share-Based Compensation, for more information.
Research and Development	Research and Development Research and development costs are expensed as incurred. The amount charged to expense was $12.8 million, $13.3 million, and $13.1 million for the years ended December 31, 2017, 2016, and 2015, respectively.
Cash and Cash Equivalents	Cash and Cash Equivalents Cash and cash equivalents include all cash balances and highly liquid investments with a stated maturity of three months or less. Cash equivalents are stated at cost, which approximates market. Cash and cash equivalents totaled $216.9 million and $239.3 million at December 31, 2017 and 2016, respectively, which included cash equivalents of $160.2 million
Trade Accounts Receivable, Allowance for Doubtful Accounts, and Customer Deductions	Trade Accounts Receivable, Allowance for Doubtful Accounts, and Customer Deductions Trade accounts receivable are stated at the amount we expect to collect. The collectability of our accounts receivable is based upon a combination of factors. In circumstances where a specific customer is unable to meet its financial obligations to PCA (e.g., bankruptcy filings, substantial downgrading of credit sources), a specific reserve for bad debts is recorded against amounts due to the Company to reduce the net recorded receivable to the amount the Company reasonably believes will be collected. For all other customers, reserves for bad debts are recognized based on historical collection experience. If collection experience deteriorates (i.e., higher than expected defaults or an unexpected material adverse change in a major customer’s ability to meet its financial obligations to the Company), the estimate of the recoverability of amounts due could be reduced by a material amount. We periodically review our allowance for doubtful accounts and adjustments to the valuation allowance are recorded as income or expense. Trade accounts receivable balances that remain outstanding after we have used reasonable collection efforts are written off through a charge to the valuation allowance and a credit to accounts receivable. At December 31, 2017 and 2016, the allowance for doubtful accounts was $4.2 million and $3.8 million, respectively. The customer deductions reserve represents the estimated amount required for customer returns, allowances, and earned discounts. Based on the Company’s experience, customer returns, allowances, and earned discounts have averaged approximately 1% of gross selling price. Accordingly, PCA reserves 1% of its open customer accounts receivable balance for these items. The reserves for customer deductions of $8.4 million
Derivative Instruments and Hedging Activities	Derivative Instruments and Hedging Activities The Company records its derivatives, if any, in accordance with ASC 815, Derivatives and Hedging
Fair Value Measurements	Fair Value Measurements PCA measures the fair value of its financial instruments in accordance with ASC 820, Fair Value Measurements and Disclosures Level 1 — Valuations based on quoted prices for identical assets and liabilities in active markets. Level 2 — Valuations based on observable inputs other than quoted prices included in Level 1, such as quoted prices for similar assets and liabilities in active markets, quoted prices for identical or similar assets and liabilities in markets that are not active, or other inputs that are observable or can be corroborated by observable market data. Level 3 — Valuations based on unobservable inputs in which there is little or no market data, which require the reporting entity to develop its own assumptions. Financial instruments measured at fair value on a recurring basis include the fair value of our pension and postretirement benefit assets and liabilities. See Note 10, Employee Benefit Plans and Other Postretirement Benefits for more information. Other assets and liabilities measured and recognized at fair value on a nonrecurring basis include assets acquired and liabilities assumed in acquisitions and our asset retirement obligations. Given the nature of these assets and liabilities, evaluating their fair value from the perspective of a market participant is inherently complex. Assumptions and estimates about future values can be affected by a variety of internal and external factors. Changes in these factors may require us to revise our estimates and could require us to retroactively adjust provisional amounts that we recorded for the fair values of assets acquired and liabilities assumed in connection with business combinations. These adjustments could have a material effect on our financial condition and results of operations. See Note 3, Acquisitions and Dispositions, and Note 11, Asset Retirement Obligations, for more information.
Inventory Valuation	Inventory Valuation We value our raw materials, work in process, and finished goods inventories using lower of cost, as determined by the average cost method, or market. Supplies and materials are valued at the first-in, first-out (FIFO) or average cost methods.
Property, Plant, and Equipment	Property, Plant, and Equipment Property, plant, and equipment are recorded at cost. Cost includes expenditures for major improvements and replacements and the amount of interest cost associated with significant capital additions. Repairs and maintenance costs are expensed as incurred .
Depreciation and Useful Life	Depreciation is computed on the straight-line basis over the estimated useful lives of the related assets. Assets under capital leases are depreciated on the straight-line method over the term of the lease or the useful life, if shorter. The following lives are used for the various categories of assets: Buildings and land improvements 5 to 40 years Machinery and equipment 3 to 25 years Trucks and automobiles 3 to 10 years Furniture and fixtures 3 to 20 years Computers and hardware 3 to 10 years Leasehold improvements Period of the lease life, if shorter
Leases	Leases We assess lease classification as either capital or operating at lease inception or upon modification. We lease some of our locations, as well as other property and equipment, under operating leases. For purposes of determining straight-line rent expense, the lease term is calculated from the date of possession of the facility, including any periods of free rent and any renewal option periods that are reasonably assured of being exercised.
Long-Lived Asset Impairment	Long-Lived Asset Impairment Long-lived assets other than goodwill and other intangibles are reviewed for impairment in accordance with provisions of ASC 360, Property, Plant and Equipment
Goodwill and Intangible Assets	Goodwill and Intangible Assets The Company has capitalized certain intangible assets, primarily goodwill, customer relationships, and trademarks and trade names, based on their estimated fair value at the date of acquisition. Amortization is provided for customer relationships on a straight-line basis over periods ranging from ten to 40 years, and trademarks and trade names over periods ranging from two to 20 years. Goodwill, which amounted to $883.2 million and $737.9 million for the years ended December 31, 2017 and 2016, respectively, is not amortized but is subject to an annual impairment test in accordance with ASC 350, Intangibles - Goodwill and Other
Pension and Postretirement Benefits	Pension and Postretirement Benefits Several estimates and assumptions are required to record pension costs and liabilities, including discount rate, return on assets, and longevity and service lives of employees. We review and update these assumptions annually unless a plan curtailment or other event occurs, requiring we update the estimates on an interim basis. While we believe the assumptions used to measure our pension and postretirement benefit obligations are reasonable, differences in actual experience or changes in assumptions may materially affect our pension and postretirement benefit obligations and future expense. See Note 10, Employee Benefit Plans and Other Postretirement Benefits, for additional information. For postretirement health care plan accounting, the Company reviews external data and its own historical trends for health care costs to determine the health care cost trend rate assumption.
Environmental Matters	Environmental Matters Environmental expenditures that extend the life of the related property or mitigate or prevent future environmental contamination are capitalized. Liabilities are recorded for environmental contingencies when such costs are probable and reasonably estimable. These liabilities are adjusted as further information develops or circumstances change. Environmental expenditures related to existing conditions resulting from past or current operations from which no current or future benefit is discernible are expensed as incurred.
Asset Retirement Obligations	Asset Retirement Obligations The Company accounts for its retirement obligations related predominantly to landfill closure, wastewater treatment pond dredging, closed-site monitoring costs, and certain leasehold improvements under ASC 410, Asset Retirement and Environmental Obligations
Deferred Financing Costs	Deferred Financing Costs PCA has capitalized certain costs related to obtaining its financing. These costs are amortized to interest expense using the effective interest rate method over the terms of the related financing, which range from five to ten years. At December 31, 2017 and 2016 deferred financing costs were $15.3 million and $12.4 million, respectively, and were recorded in “Long-Term Debt” on our Consolidated Balance Sheets.
Cutting Rights and Fiber Farms	Cutting Rights and Fiber Farms We lease the cutting rights to approximately 75,000 acres of timberland, and we lease 9,000 acres of land where we operate fiber farms as a source of future fiber supply. For our cutting rights and fiber farms, we capitalize the annual lease payments and reforestation costs associated with these leases. Costs are recorded as depletion when the timber or fiber is harvested and used in operations or sold to customers. Capitalized long-term lease costs for our cutting rights and fiber farms, primarily recorded in “Other long-term assets” on our Consolidated Balance Sheets, were $31.5 million and $43.9 million as of December 31, 2017 and 2016, respectively. The amount of depletion expense was $5.2 million, $4.7 million, and $7.0 million for the years ended December 31, 2017, 2016, and 2015, respectively. Additionally, in conjunction with the announced conversion of the No. 3 machine at the Wallula mill to kraft linerboard, management performed a recoverability test on associated fiber farms and deemed the asset group to not be fully recoverable. As a result of the recoverability calculation on the fiber farm asset group, the Company recorded an impairment loss of $13.5 million in the third quarter of 2017.
Deferred Software Costs	Deferred Software Costs PCA capitalizes costs related to the purchase and development of software, which is used in its business operations. The costs attributable to these software systems are amortized over their estimated useful lives based on various factors such as the effects of obsolescence, technology, and other economic factors. Net capitalized software costs recorded in “Other long-term assets” on our Consolidated Balance Sheets were $3.3 million and $4.5 million for the years ended December 31, 2017 and 2016, respectively. Software amortization expense was $2.3 million, $2.5 million, and $3.0 million for the years ended December 31, 2017, 2016, and 2015, respectively.
Income Taxes	Income Taxes PCA utilizes the liability method of accounting for income taxes whereby it recognizes deferred tax assets and liabilities for the future tax consequences of temporary differences between the tax basis of assets and liabilities and their reported amounts in the financial statements. Deferred tax assets will be reduced by a valuation allowance if, based upon management’s estimates, it is more likely than not that a portion of the deferred tax assets will not be realized in a future period. The estimates utilized in the recognition of deferred tax assets are subject to revision in future periods based on new facts or circumstances. PCA’s practice is to recognize interest and penalties related to unrecognized tax benefits in income tax expense.
Trade Agreements	Trade Agreements PCA regularly trades containerboard with other manufacturers primarily to reduce shipping costs. These agreements are entered into with other producers on an annual basis, pursuant to which both parties agree to ship an identical number of tons of containerboard to each other within the agreement period. These agreements lower transportation costs by allowing each party’s containerboard mills to ship containerboard to the other party’s closer corrugated products plant. PCA tracks each shipment to ensure that the other party’s shipments to PCA match PCA’s shipments to the other party during the agreement period. Such transfers are possible because containerboard is a commodity product with no distinguishing product characteristics. These transactions are accounted for at carrying value, and revenue is not recorded as the transactions do not represent the culmination of an earnings process. The transactions are recorded into inventory accounts, and no sale or income is recorded until such inventory is converted to a finished product and sold to an end-use customer. Business Combinations The Company accounts for acquisitions under ASC 805, Business Combinations Clarifying the Definition of a Business
New and Recently Adopted Accounting Pronouncements	New and Recently Adopted Accounting Standards Effective January 1, 2018, the Company will adopt Financial Accounting Standards Board (“FASB”) ASU 2014-09 (Topic 606): Revenue from Contracts with Customers The Company will adopt the standard utilizing the modified retrospective method, in which case the cumulative effect of applying the standard is recognized at the date of initial application on January 1, 2018. We established a transition team to analyze the impact of the standard on our revenue contracts by reviewing our current accounting policies and practices and identifying potential differences that would result from applying the requirements of the new standard. Specifically, we identified significant revenue streams within each of our reportable segments and reviewed representative contracts to identify corresponding purchase obligations, variable consideration, acquisition costs and fulfillment costs. In addition, we identified and assessed appropriate changes to our business processes, systems and controls to support revenue recognition and disclosures under the new standard. This team has reported its findings and progress of the project to management and the Audit Committee on a periodic basis. During our assessment, the Company considered whether the adoption would require a transition from point-in-time revenue recognition to an over-time approach for products produced by the Company without an alternative use, which would result in acceleration of revenue. The Company determined that based on the express terms included in the majority of its contracts, and the Company’s standard terms and conditions, an enforceable right of payment that includes a reasonable profit throughout the duration of . While the adoption of ASU 2014-09 on January 1, 2018 will not have a material effect on the Company’s financial position or results of operations, the new standard requires additional disclosures around revenue recognition in the notes to the financial statements, which the Company will comply with beginning in 2018. Additionally, the following adjustment and reclassification of certain costs will be made in 2018: a. The b. The Effective January 1, 2017, the Company adopted ASU 2016-09 (Topic 718): Improvements to Employee Share-Based Payment Accounting Effective January 1, 2017, the Company prospectively adopted ASU 2015-11 (Topic 330): Simplifying the Measurement of Inventory In January 2017, the FASB issued ASU 2017-04 (Topic 350): Intangibles - Goodwill and Other - Simplifying the Test for Goodwill Impairment In March 2017, the FASB issued ASU 2017-07, Compensation: Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost. In May 2017, the FASB issued ASU 2017-09 Compensation - Stock Compensation Scope of Modification Accounting In January 2017, the FASB issued ASU 2017-01 (Topic 805): Clarifying the Definition of a Business In August 2016, the FASB issued ASU 2016-15 (Topic 230), Statement of Cash Flows: Classification of Certain Cash Receipts and Cash Payments In February 2016, the FASB issued ASU 2016-02 (Topic 842): Leases There were no other accounting standards recently issued that had or are expected to have a material impact on our financial position or results of operations.

Summary of Significant Accoun28

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Components of Inventories	The components of inventories were as follows (dollars in millions): December 31 2017 2016 Raw materials $ 279.8 $ 271.9 Work in process 12.6 12.9 Finished goods 217.0 206.5 Supplies and materials 253.1 232.3 Inventories $ 762.5 $ 723.6
Property, Plant and Equipment (at cost)	Property, plant, and equipment consisted of the following (dollars in millions): December 31 2017 2016 Land and land improvements $ 156.0 $ 149.7 Buildings 729.8 717.1 Machinery and equipment 5,162.5 4,951.4 Construction in progress 194.5 125.4 Other 68.4 66.7 Property, plant and equipment, at cost 6,311.2 6,010.3 Less accumulated depreciation (3,386.3 ) (3,114.6 ) Property, plant and equipment, net $ 2,924.9 $ 2,895.7
Property, Plant and Equipment Estimated Useful Lives	Depreciation is computed on the straight-line basis over the estimated useful lives of the related assets. Assets under capital leases are depreciated on the straight-line method over the term of the lease or the useful life, if shorter. The following lives are used for the various categories of assets: Buildings and land improvements 5 to 40 years Machinery and equipment 3 to 25 years Trucks and automobiles 3 to 10 years Furniture and fixtures 3 to 20 years Computers and hardware 3 to 10 years Leasehold improvements Period of the lease life, if shorter

Acquisitions and Dispositions (

Acquisitions and Dispositions (Tables)	12 Months Ended
	Dec. 31, 2017
Sacramento Container Corporation
Schedule of Business Acquisitions, by Acquisition	The total purchase price has been preliminarily allocated to tangible and intangible assets acquired and liabilities assumed based on respective fair values, as follows (dollars in millions): Initial Allocation Adjustments Revised Allocation Goodwill $ 151.1 $ — $ 151.1 Other intangible assets 72.6 — 72.6 Property, plant and equipment 26.7 — 26.7 Other net assets 14.6 8.8 23.4 Net assets acquired $ 265.0 $ 8.8 $ 273.8
Columbus Container Inc
Schedule of Business Acquisitions, by Acquisition	The total purchase price has been allocated to tangible and intangible assets acquired and liabilities assumed based on respective fair values, as follows (dollars in millions): 12/31/16 Allocation Adjustments Revised Allocation Goodwill $ 36.6 $ (4.7 ) $ 31.9 Other intangible assets 26.3 6.0 32.3 Property, plant and equipment 27.2 1.0 28.2 Other net assets 9.6 (0.1 ) 9.5 Net assets acquired $ 99.7 $ 2.2 $ 101.9
TimBar Corporation
Schedule of Business Acquisitions, by Acquisition	The total purchase price has been allocated to tangible and intangible assets acquired and liabilities assumed based on respective fair values, as follows (dollars in millions): 12/31/16 Allocation Adjustments Revised Allocation Goodwill $ 157.3 $ (1.1 ) $ 156.2 Other intangible assets 94.4 94.4 Property, plant and equipment 95.3 95.3 Other net assets 38.6 38.6 Net assets acquired $ 385.6 $ (1.1 ) $ 384.5

Earnings Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2017
Earnings Per Share [Abstract]
Computation of Basic and Diluted Income Per Common Share	The following table sets forth the computation of basic and diluted income per common share for the periods presented (dollars and shares in millions, except per share data). Year Ended December 31 2017 2016 2015 Numerator: Net income $ 668.6 $ 449.6 $ 436.8 Less: distributed and undistributed earnings allocated to participating securities (5.6 ) (4.4 ) (5.2 ) Net income attributable to common stockholders $ 663.0 $ 445.2 $ 431.6 Denominator: Weighted average common shares outstanding 93.5 93.5 96.6 Effect of dilutive securities 0.2 0.2 0.1 Diluted common shares outstanding 93.7 93.7 96.7 Basic income per common share $ 7.09 $ 4.76 $ 4.47 Diluted income per common share $ 7.07 $ 4.75 $ 4.47

Other Expense, Net (Tables)

Other Expense, Net (Tables)	12 Months Ended
	Dec. 31, 2017
Other Income And Expenses [Abstract]
Components of Other Income (Expense), Net	The components of other income (expense), net, were as follows (dollars in millions) Year Ended December 31, 2017 2016 2015 Wallula mill restructuring (a) $ (23.1 ) $ — $ — Asset disposals and write-offs (10.5 ) (11.9 ) (14.0 ) Acquisition and integration related costs (b)(c)(d) (0.8 ) (3.3 ) (12.9 ) Expiration of timberland repurchase option (e) 2.0 — — Hexacomb working capital adjustment (f) 2.3 — — Facilities closure and other costs (g) 5.9 (10.3 ) — DeRidder mill incident (h) 9.7 — — Ceased production of market pulp at Wallula (i) — (0.6 ) — DeRidder restructuring (j) — — 7.1 Sale of St. Helens Paper Mill Site (k) — — 6.7 Refundable state tax credit (l) — — 3.6 Other (3.9 ) 1.8 2.8 Total $ (18.4 ) $ (24.3 ) $ (6.7 ) (a) Includes $23.1 million of charges related to our determination to discontinue production of uncoated free sheet and coated one-side grades at the Wallula, Washington mill in the second quarter of 2018 and convert the No. 3 paper machine to a high-performance 100% virgin kraft linerboard machine. (b) For 2017, includes charges related to the Sacramento Container Corporation acquisition and integration costs related to other recent acquisitions. (c) For 2016, includes charges related to the acquisition and integration of TimBar Corporation. (d) For 2015, includes Boise acquisition integration-related and other costs, which primarily relate to severance, retention, travel, and professional fees. (e) Includes a gain related to the expiration of a repurchase option corresponding to timberland previously sold. (f) Includes income related to a working capital adjustment from the April 2015 sale of our Hexacomb corrugated manufacturing operations in Europe and Mexico. (g) For 2017, includes income primarily related to the sale of land corresponding to the closure of a corrugated products facility, partially offset by closure costs related to corrugated products facilities, a paper administration facility, a corporate administration facility, and a lump sum settlement of a multiemployer pension plan withdrawal liability for one of our corrugated products facilities. For 2016, includes expenses related to the closure of corrugated products facilities and a paper administration facility and a lump sum settlement of a multiemployer pension plan withdrawal liability for one of our corrugated products facilities. (h) Includes the property damage and business interruption insurance recoveries and corresponding costs related to the February 2017 explosion at our DeRidder, Louisiana mill. (i) Includes costs related to ceased softwood market pulp operations at our Wallula, Washington mill and the permanent shutdown of the No. 1 machine. (j) Includes $7.1 million of income from vendor settlements related to our restructuring activities at our DeRidder, Louisiana mill. (k) Includes a gain related to the sale of the remaining land, buildings, and equipment at our paper mill site in St. Helens, Oregon where we ceased paper production in December 2012. (l) Includes a tax credit from the State of Louisiana related to capital investment and the jobs retained at the DeRidder, Louisiana mill.

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Components of Consolidated Income Tax Provision	The following is an analysis of the components of the consolidated income tax provision (dollars in millions): Year Ended December 31 2017 2016 2015 Current income tax provision (benefit) - U.S. federal $ 209.3 $ 213.6 $ 205.1 State and local 34.9 29.1 20.5 Foreign 0.3 0.2 0.4 Total current provision for taxes 244.5 242.9 226.0 Deferred - U.S. federal (90.2 ) (1.2 ) (3.8 ) State and local 5.7 (3.0 ) 5.6 Foreign — 0.2 (0.1 ) Total deferred provision (benefit) for taxes (84.5 ) (4.0 ) 1.7 Total provision (benefit) for taxes $ 160.0 $ 238.9 $ 227.7
Summary of Effective Tax Rate	The effective tax rate varies from the U.S. federal statutory tax rate principally due to the following (dollars in millions): 2017 2016 2015 Provision computed at U.S. federal statutory rate of 35% $ 290.0 $ 241.0 $ 232.6 Federal tax reform (127.2 ) — — State and local taxes, net of federal benefit 24.0 19.8 20.0 Domestic manufacturers deduction (21.1 ) (21.1 ) (19.9 ) Other (5.7 ) (0.8 ) (5.0 ) Total $ 160.0 $ 238.9 $ 227.7
Details of Scheduled Expiration Dates of Tax Effected Net Operating Loss (NOL) and Other Tax Carryforwards	The following details the scheduled expiration dates of our tax effected net operating loss (NOL) and other tax carryforwards at December 31, 2017 (dollars in millions): 2018 Through 2027 2028 Through 2037 Indefinite Total U.S. federal NOLs $ — $ 35.8 $ — $ 35.8 State taxing jurisdiction NOLs 1.4 0.9 — 2.3 U.S. federal tax credit carryforwards — 0.1 — 0.1 U.S. federal and non-U.S. capital loss carryforwards 3.0 — 0.1 3.1 Total $ 4.4 $ 36.8 $ 0.1 $ 41.3
Deferred Income Tax Assets and Liabilities	Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts for income tax purposes. Deferred income tax assets and liabilities at December 31 are summarized as follows (dollars in millions): December 31 2017 2016 Deferred tax assets: Accrued liabilities $ 13.7 $ 18.1 Employee benefits and compensation 21.1 45.9 Inventories 15.4 9.9 Net operating loss carryforwards 38.1 67.4 Restricted stock and performance units 9.0 11.7 Pension and postretirement benefits 90.6 136.5 Derivatives 6.1 11.5 Capital loss and general business credit carryforwards 3.2 5.3 Gross deferred tax assets $ 197.2 $ 306.3 Valuation allowance (a) (3.1 ) (5.2 ) Net deferred tax assets $ 194.1 $ 301.1 Deferred tax liabilities: Property, plant and equipment $ (368.6 ) $ (537.0 ) Goodwill and intangible assets (65.0 ) (98.8 ) Total deferred tax liabilities $ (433.6 ) $ (635.8 ) Net deferred tax liabilities (b) $ (239.5 ) $ (334.7 ) (a) Deferred tax assets are reduced by a valuation allowance when it is more likely than not that some portion of the deferred tax assets will not be realized. Both the 2017 and 2016 valuation allowance relates to capital losses. We do not expect to generate capital gains before the capital losses expire. If or when recognized, the tax benefits relating to the reversal of any or all of the valuation allowance would be recognized as a benefit to income tax expense. (b) As of December 31, 2017, we did not recognize U.S. deferred income taxes on our cumulative total of undistributed foreign earnings for our foreign subsidiaries. We indefinitely reinvest our earnings in operations outside the United States. It is not practicable to determine the amount of unrecognized deferred tax liability on these undistributed earnings because the actual tax liability, if any, is dependent on circumstances existing when the repatriation occurs.
Summary of Changes Related to PCA’s Gross Unrecognized Tax Benefits Excluding Interest and Penalties	The following table summarizes the changes related to PCA’s gross unrecognized tax benefits excluding interest and penalties (dollars in millions): 2017 2016 2015 Balance as of January 1 $ (5.2 ) $ (5.8 ) $ (4.4 ) Increases related to prior years’ tax positions — — (2.8 ) Increases related to current year tax positions (0.4 ) (0.5 ) (0.4 ) Decreases related to prior years' tax positions — 0.1 — Settlements with taxing authorities — 0.3 0.7 Expiration of the statute of limitations 0.8 0.7 1.1 Balance at December 31 $ (4.8 ) $ (5.2 ) $ (5.8 )

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2017
Goodwill And Intangible Assets Disclosure [Abstract]
Schedule of Goodwill	Changes in the carrying amount of our goodwill were as follows (dollars in millions): Packaging Paper Goodwill Balance at January 1, 2016 $ 488.8 $ 55.2 $ 544.0 Acquisitions (a) 193.9 — 193.9 Balance at December 31, 2016 $ 682.7 $ 55.2 $ 737.9 Acquisitions (b)(c) 145.3 — 145.3 Balance at December 31, 2017 $ 828.0 $ 55.2 $ 883.2 (a) In connection with the August 2016 acquisition of TimBar, the Company recoded $157.3 million of goodwill in the Packaging segment. In November 2016, we acquired Columbus Container and recorded $36.6 million of goodwill in the Packaging segment. (b) In connection with the October 2017 acquisition of Sacramento Container, the Company recorded $151.1 million of goodwill in the Packaging segment. (c) During 2017, the Company recorded opening balance sheet adjustments related to the TimBar and Columbus Container acquisitions resulting in a decrease to goodwill of $5.8 million.
Components of Intangible Assets	The weighted average useful life, gross carrying amount, and accumulated amortization of our intangible assets were as follows (dollars in millions): As of December 31, 2017 As of December 31, 2016 Weighted Average Useful Life (in Years) Gross Carrying Amount Accumulated Amortization Weighted Average Remaining Useful Life (in Years) Gross Carrying Amount Accumulated Amortization Customer relationships (d) 11.8 $ 497.8 $ 109.8 13.1 $ 424.5 $ 79.8 Trademarks and trade names (d) 9.8 32.9 13.2 10.5 27.7 8.1 Other (d) 3.6 4.3 2.0 4.3 4.2 1.4 Total intangible assets (excluding goodwill) 11.7 $ 535.0 $ 125.0 12.9 $ 456.4 $ 89.3 (d) In connection with the October 2017 acquisition of Sacramento Container, the Company recorded intangible assets of $68.4 million for customer relationships, $4.1 million for trade names, and $0.1 million for other intangibles. In August 2016, we acquired TimBar and recorded intangible assets of $88.0 million for customer relationships, $4.9 million for trade names, and $1.5 million for other intangibles. In November 2016, we acquired Columbus Container and recorded intangible assets of $30.0 million for customer relationships, $2.2 million for trade names, and $0.2 million for other intangibles. See Note 3, Acquisitions, for more information.

Accrued Liabilities (Tables)

Accrued Liabilities (Tables)	12 Months Ended
	Dec. 31, 2017
Accrued Liabilities Current And Noncurrent [Abstract]
Components of Accrued Liabilities	The components of accrued liabilities were as follows (dollars in millions): December 31, 2017 2016 Compensation and benefits $ 127.5 $ 120.4 Medical insurance and workers’ compensation 23.9 28.8 Customer volume discounts and rebates 23.4 18.9 Franchise, property, sales and use taxes 16.0 16.7 Environmental liabilities and asset retirement obligations 4.0 6.4 Severance, retention, and relocation 3.1 3.0 Other 5.3 7.0 Total $ 203.2 $ 201.2

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Summary of Debt	At December 31, 2017 and 2016, our long-term debt and interest rates on that debt were as follows (dollars in millions): December 31, 2017 December 31, 2016 Amount Interest Rate Amount Interest rate Revolving Credit Facility, due August 2021 $ — — % $ — — % Five-Year Term Loan, due August 2021 — — % 380.2 2.02 % Seven-Year Term Loan, due October 2020 — — % 630.5 2.40 % 6.50% Senior Notes due March 2018 150.0 6.50 % 150.0 6.50 % 2.45% Senior Notes, net of discount of $0.5 million as of December 31, 2017 due December 2020 499.5 2.45 % — — % 3.90% Senior Notes, net of discounts of $0.2 million and $0.2 million as of December 30, 2017 and 2016, respectively, due June 2022 399.8 3.90 % 399.8 3.90 % 4.50% Senior Notes, net of discount of $1.2 million a $1.4 million as of December 30, 2017 and 2016, respectively, due November 2023 698.8 4.50 % 698.6 4.50 % 3.65% Senior Notes, net of discount of $0.8 million and $0.9 million as of December 31, 2017 and 2016, respectively, due September 2024 399.2 3.65 % 399.1 3.65 % 3.40% Senior Notes, net of discount of $1.6 million as of December 31, 2017 due December 2027 498.4 3.40 % — — % Total 2,645.7 3.80 % 2,658.2 3.54 % Less current portion 150.0 6.50 % 25.8 2.11 % Less unamortized debt issuance costs 15.3 12.5 Total long-term debt $ 2,480.4 3.64 % $ 2,620.0 3.57 %

Employee Benefit Plans and Ot36

Employee Benefit Plans and Other Postretirement Benefits (Tables)	12 Months Ended
	Dec. 31, 2017
Compensation And Retirement Disclosure [Abstract]
Schedule of Obligations and Funded Status of Defined Benefit Pension and Postretirement Benefit Plans	The following table, which includes only company-sponsored defined benefit and other postretirement benefit plans, reconciles the beginning and ending balances of the projected benefit obligation and the fair value of plan assets. We recognize the unfunded status of these plans on the Consolidated Balance Sheets, and we recognize changes in funded status in the year changes occur through the Consolidated Statements of Comprehensive Income (dollars in millions): Pension Plans Postretirement Plans Year Ended December 31 Year Ended December 31 2017 2016 2017 2016 Change in Benefit Obligation Benefit obligation at beginning of period $ 1,158.4 $ 1,092.5 $ 19.5 $ 21.4 Service cost 23.7 24.5 0.3 0.5 Interest cost 41.6 40.9 0.6 0.6 Plan amendments 17.3 1.8 (0.5 ) (5.3 ) Actuarial loss (gain) (a) 99.3 35.3 (2.2 ) 3.7 Participant contributions — — 1.3 1.3 Benefits paid (40.1 ) (36.6 ) (2.5 ) (2.7 ) Benefit obligation at plan year end $ 1,300.2 $ 1,158.4 $ 16.5 $ 19.5 Accumulated benefit obligation portion of above $ 1,237.7 $ 1,116.6 Change in Fair Value of Plan Assets Plan assets at fair value at beginning of period $ 830.4 $ 764.4 $ — $ — Actual return on plan assets 121.0 44.4 — — Company contributions 43.5 58.2 1.2 1.4 Participant contributions — — 1.3 1.3 Benefits paid (40.1 ) (36.6 ) (2.5 ) (2.7 ) Fair value of plan assets at plan year end $ 954.8 $ 830.4 $ — $ — Underfunded status $ (345.4 ) $ (328.0 ) $ (16.5 ) $ (19.5 ) Amounts Recognized on Consolidated Balance Sheets Current liabilities $ (1.4 ) $ (1.3 ) $ (1.0 ) $ (1.2 ) Noncurrent liabilities (344.0 ) (326.7 ) (15.5 ) (18.3 ) Accrued obligation recognized at December 31 $ (345.4 ) $ (328.0 ) $ (16.5 ) $ (19.5 ) Amounts Recognized in Accumulated Other Comprehensive Loss (Income) (Pre-Tax) Prior service cost (credit) $ 32.7 $ 21.1 $ (5.3 ) $ (5.0 ) Actuarial loss (gain) 208.5 183.9 (4.0 ) (1.9 ) Total $ 241.2 $ 205.0 $ (9.3 ) $ (6.9 ) (a) The actuarial loss in 2017 was due primarily to a decrease in the weighted average discount rate used to estimate our pension benefit obligations. In 2016, a decrease in the weighted average discount rate used to estimate our pension benefit obligations and changes in mortality assumptions from the Society of Actuaries resulted in an actuarial loss.
Components of Net Periodic Benefit Costs and Other Comprehensive (Income) Loss (Pretax)	The components of net periodic benefit cost and other comprehensive (income) loss (pretax) were as follows (dollars in millions): Pension Plans Postretirement Plans Year Ended December 31 Year Ended December 31 2017 2016 2015 2017 2016 2015 Service cost $ 23.7 $ 24.5 $ 24.0 $ 0.3 $ 0.5 $ 1.7 Interest cost 41.6 40.9 46.2 0.6 0.6 1.2 Expected return on plan assets (53.9 ) (49.5 ) (53.1 ) — — — Net amortization of unrecognized amounts Prior service cost (credit) 5.8 5.7 5.5 (0.2 ) (0.1 ) 0.1 Actuarial loss (gain) 7.6 5.8 8.7 (0.1 ) (0.4 ) 0.1 Net periodic benefit cost $ 24.8 $ 27.4 $ 31.3 $ 0.6 $ 0.6 $ 3.1 Changes in plan assets and benefit obligations recognized in other comprehensive (income) loss Actuarial net loss (gain) $ 32.2 $ 40.4 $ (14.5 ) $ (2.2 ) $ 3.6 $ (11.4 ) Prior service cost (credit) 17.4 1.8 3.0 (0.6 ) (5.3 ) — Amortization of prior service cost (credit) (5.8 ) (5.7 ) (5.5 ) 0.2 (0.3 ) (0.1 ) Amortization of actuarial loss (gain) (7.6 ) (5.8 ) (8.7 ) 0.1 0.8 (0.1 ) Total recognized in other comprehensive loss (income) (a) $ 36.2 $ 30.7 $ (25.7 ) $ (2.5 ) $ (1.2 ) $ (11.6 ) Total recognized in net periodic benefit cost and other comprehensive loss (income) (pre-tax) $ 61.0 $ 58.1 $ 5.6 $ (1.9 ) $ (0.6 ) $ (8.5 ) (a) Accumulated losses in excess of 10% of the greater of the projected benefit obligation or the market-related value of assets will be recognized on a straight-line basis over the average remaining service period of active employees in PCA plans (which is between seven to ten years) and over the average remaining lifetime of inactive participants of Boise plans (which is between 25 and 28 years), to the extent that losses are not offset by gains in subsequent years. The estimated net loss and prior service cost that will be amortized from “Accumulated other comprehensive loss” into net periodic benefit in 2018 is $15.8 million.
Weighted-Average Assumptions Used To Determine Benefit Obligations and Net Periodic Benefit Cost	The following table presents the assumptions used in the measurement of our benefits obligations: Pension Plans Postretirement Plans December 31 December 31 2017 2016 2015 2017 2016 2015 Weighted-Average Assumptions Used to Determine Benefit Obligations at December 31 Discount rate 3.66% 4.24% 4.51% 3.55% 3.91% 4.35% Rate of compensation increase 4.00% 4.00% 4.00% N/A N/A N/A Weighted-Average Assumptions Used to Determine Net Periodic Benefit Cost for the Years Ended December 31 Discount rate 4.24% 4.49% 4.14% 3.92% 4.17% 3.95% Expected return on plan assets 6.55% 6.57% 6.73% N/A N/A N/A Rate of compensation increase 4.00% 4.00% 4.00% N/A N/A N/A
Assumed Health Care Cost Trend Rates For Postretirement Benefits	Health Care Cost Trend Rate Assumptions. PCA assumed health care cost trend rates for its postretirement benefits plans were as follows: 2017 2016 2015 Health care cost trend rate assumed for next year 7.57% 7.35% 7.60% Rate to which the cost trend rate is assumed to decline (the ultimate trend rate) 4.44% 4.50% 4.50% Year that the rate reaches the ultimate trend rate 2027 2025 2024
Schedule of Effects of One-Percentage Point Change In Assumed Health Care Cost Trend Rates on Postretirement Benefits	A one-percentage point change in assumed health care cost trend rates would have the following effects on the 2017 postretirement benefit obligation and the 2016 net post retirement benefit cost (dollars in millions): 1-Percentage Point Increase 1-Percentage Point Decrease Effect on postretirement benefit obligation $ 0.6 $ (0.6 ) Effect on net postretirement benefit cost 0.1 —
Schedule of Pension Plans' Assets Investment Policies and Strategies	Assets of our pension plans were invested in the following classes of securities at December 31, 2017 and 2016: Percentage of Fair Value at December 31, 2017 2016 Fixed income securities 21 % 54 % International equity securities 6 % 23 % Domestic equity securities 9 % 21 % Real estate securities — 1 % Other 64 % 1 % Upon completion of the transfer on January 5, 2018, the pension plan assets were invested in the following classes of securities: Percentage of Fair Value at January 5, 2018 Fixed income securities 52 % International equity securities 28 % Domestic equity securities 20 %
Schedule of Pension Plans' Assets Fair Value Measured On a Recurring Basis	The following tables set forth, by level within the fair value hierarchy, discussed in Note 2, Summary of Significant Accounting Policies, the pension plan assets, by major asset category, at fair value at December 31, 2017 and 2016 (dollars in millions): Fair Value Measurements at December 31, 2017 Asset Category Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Cash and short-term investments (a) $ 602.4 $ 5.7 $ — $ 608.1 Mutual funds: International equities 56.1 — — 56.1 Fixed income 95.4 — — 95.4 Common/collective trust funds (b): Domestic equities — 84.1 — 84.1 International equities — 5.6 — 5.6 Fixed income — 59.8 — 59.8 Corporate and government bonds: Fixed income 41.3 — — 41.3 Private equity securities (c) — — 4.2 4.2 Total securities at fair value $ 795.2 $ 155.2 $ 4.2 $ 954.6 Receivables and accrued expenses 0.2 Total fair value of plan assets $ 954.8 Fair Value Measurements at December 31, 2016 Asset Category Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Cash and short-term investments $ — $ 1.5 $ — $ 1.5 Mutual funds: Domestic equities 65.7 — — 65.7 International equities 68.7 — — 68.7 Real estate 9.6 — — 9.6 Fixed income 108.4 64.8 — 173.2 Common/collective trust funds (b): — Domestic equities — 107.9 — 107.9 International equities — 124.5 — 124.5 Fixed income — 271.6 — 271.6 Private equity securities (c) — — 5.7 5.7 Total securities at fair value $ 252.4 $ 570.3 $ 5.7 $ 828.4 Receivables and accrued expenses 2.0 Total fair value of plan assets $ 830.4 (a) Short-term investments and the Boise pension plan assets classified as cash as of December 31, 2017. The Boise pension plan assets were subsequently allocated to equities and fixed income securities on January 5, 2018 after consolidating with the PCA pension plan assets under one trustee. (b) Investments in common/collective trust funds valued using net asset values (NAV) provided by the administrator of the funds. The NAV is based on the value of the underlying assets owned by the fund, minus its liabilities, and then divided by the number of units outstanding. While the underlying assets are actively traded on an exchange, the funds are not. There are currently no redemption restrictions on these investments. There are certain funds with one-day redeemable notice. (c) Investments in this category are invested in the Pantheon Global Secondary Fund IV, LP. The fund specializes in investments in the private equity secondary market and occasionally directly in private companies to maximize capital growth. Fund investments are carried at fair value as determined quarterly using the market approach to estimate the fair value of private investments. The market approach utilizes prices and other relevant information generated by market transactions, type of security, size of the position, degree of liquidity, restrictions on the disposition, latest round of financing data, current financial position, and operating results, among other factors. In circumstances where fair values are not provided with respect to any of the company's fund investments, the investment advisor will seek to determine the fair value of such investments based on information provided by the general partners or managers of such funds or from other sources. Audited financial statements are provided by fund management annually. Notwithstanding the above, the variety of valuation bases adopted and quality of management data of the ultimate underlying investee companies means that there are inherent difficulties in determining the value of the investments. Amounts realized on the sale of these investments may differ from the calculated values. Boise had originally committed to a $15.0 million investment, with $5.0 million of the commitment unfunded at December 31, 2017.
Summary of Changes in Pension Plans' Level 3 Assets	The following table sets forth a summary of changes in the fair value of the pension plans' Level 3 assets for the year ended December 31, 2017 (dollars in millions): 2017 Balance, beginning of year $ 5.7 Acquisitions — Purchases — Sales (1.5 ) Unrealized gain — Balance, end of year $ 4.2
Schedule of Estimated Benefit Payments	The following are estimated benefit payments to be paid to current plan participants by year (dollars in millions). Qualified pension benefit payments are paid from plan assets, while nonqualified pension benefit payments are paid by the Company. Pension Plans Postretirement Plans 2018 $ 45.4 $ 1.0 2019 49.3 1.0 2020 53.2 1.0 2021 57.0 0.9 2022 - 2025 407.9 5.4

Asset Retirement Obligations (T

Asset Retirement Obligations (Tables)	12 Months Ended
	Dec. 31, 2017
Asset Retirement Obligation [Abstract]
Changes to Asset Retirement Obligation	The following table describes changes to the asset retirement obligation liability (dollars in millions): Year Ended December 31 2017 2016 Asset retirement obligation at beginning of period $ 28.0 $ 26.2 Accretion expense 1.3 2.3 Payments (2.3 ) (2.2 ) Revisions in estimated cash flows 7.9 1.2 Liabilities incurred 0.2 0.5 Asset retirement obligation at end of period $ 35.1 $ 28.0

Share-Based Compensation (Table

Share-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2017
Share Based Compensation [Abstract]
Summary of Restricted Stock Activity	A summary of the Company’s restricted stock activity follows: 2017 2016 2015 Shares Weighted Average Grant- Date Fair Value Shares Weighted Average Grant- Date Fair Value Shares Weighted Average Grant- Date Fair Value Restricted stock at January 1 786,079 $ 63.44 1,007,794 $ 49.47 1,184,299 $ 41.71 Granted 173,199 107.57 242,835 67.48 218,957 65.16 Vested (a) (213,992 ) 51.37 (443,627 ) 34.11 (389,481 ) 32.77 Forfeitures (5,554 ) 69.03 (20,923 ) 59.63 (5,981 ) 66.42 Restricted stock at December 31 739,732 $ 77.23 786,079 $ 63.44 1,007,794 $ 49.47 (a) The total fair value of awards upon vesting for the years ended December 31, 2017, 2016, and 2015 was $23.3 million, .
Summary of Performance Units Activity	The awards are valued at the closing price of the Company’s stock on the grant date and expensed over the requisite service period based on the most probable number of awards expected to vest. 2017 2016 2015 Units Weighted Average Grant- Date Fair Value Units Weighted Average Grant- Date Fair Value Units Weighted Average Grant- Date Fair Value Performance units at January 1 232,088 $ 62.68 175,675 $ 59.94 127,489 $ 58.25 Granted 61,861 108.19 77,017 67.57 53,102 65.04 Vested (a) (67,391 ) 56.08 (20,604 ) 57.58 (4,916 ) 71.19 Performance units at December 31 226,558 $ 77.07 232,088 $ 62.68 175,675 $ 59.94 (a) The total fair value of awards upon vesting for the years ended December 31, 2017, 2016, and 2015 was $7.5 million, $1.1 million, and $0.3 million, respectively. Upon vesting of the awards in 2016 and 2015, PCA issued 21,111 and 5,090 shares, which included 507 and 174 shares, respectively, for dividends accrued during the vesting period.
Compensation Expense For Restricted Stock and Performance Units	Compensation expense for share-based awards recognized in the Consolidated Statements of Income, net of forfeitures was as follows (dollars in millions): Year Ended December 31 2017 2016 2015 Restricted stock $ 15.0 $ 15.8 $ 15.2 Performance units 5.6 3.9 3.0 Impact on income before income taxes 20.6 19.7 18.2 Income tax benefit (7.9 ) (7.7 ) (7.1 ) Impact on net income $ 12.7 $ 12.0 $ 11.1
Unrecognized Compensation For Restricted Stock and Performance Units	The unrecognized compensation expense for all share-based awards was as follows (dollars in millions): December 31, 2017 Unrecognized Compensation Expense Remaining Weighted Average Recognition Period (in years) Restricted stock $ 30.6 2.5 Performance units 9.8 2.8 Total unrecognized share-based compensation expense $ 40.4 2.6

Derivative Instruments and He39

Derivative Instruments and Hedging Activities (Tables)	12 Months Ended
	Dec. 31, 2017
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Impact of Derivative Instruments On Statements of Income and Accumulated OCI	The impact of derivative instruments on the consolidated statements of income and accumulated OCI was as follows (dollars in millions): Net Loss Recognized in Accumulated OCI (Effective Portion) December 31, 2017 2016 Treasury locks, net of tax $ (14.2 ) $ (17.7 ) Loss Reclassified from Accumulated OCI into Income (Effective Portion) Year Ended December 31, 2017 2016 2015 Amortization of treasury locks (included in interest expense, net) $ (5.7 ) $ (5.7 ) $ (5.7 )

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2017
Equity [Abstract]
Share Repurchase Program	Share repurchase activity in 2015 and 2016 follows (in millions, except share and per share amounts). Shares Weighted Average Price Per Share Total 2015 2,326,493 $ 66.50 $ 154.7 2016 1,987,187 50.49 100.3
Components of Changes in Accumulated Other Comprehensive Income (AOCI)	Changes in AOCI, net of taxes, by component follows (dollars in millions). Amounts in parentheses indicate losses. Foreign Currency Translation Adjustments Unrealized Loss On Treasury Locks, Net Unrealized Loss on Foreign Exchange Contracts Unfunded Employee Benefit Obligations Total Balance at December 31, 2016 $ (0.1 ) $ (17.7 ) $ (0.3 ) $ (121.5 ) $ (139.6 ) Other comprehensive income before reclassifications — — — (28.8 ) (28.8 ) Amounts reclassified from AOCI (0.2 ) 3.5 — 8.2 11.5 Net current-period other comprehensive income (0.2 ) 3.5 — (20.6 ) (17.3 ) Balance at December 31, 2017 $ (0.3 ) $ (14.2 ) $ (0.3 ) $ (142.1 ) $ (156.9 )
Reclassifications Out of Accumulated Other Comprehensive Income (AOCI)	The following table presents information about reclassifications out of AOCI (dollars in millions). Amounts in parentheses indicate expenses in the Consolidated Statements of Income. Amounts Reclassified from AOCI Year Ended December 31, Details about AOCI Components 2017 2016 Unrealized loss on treasury locks, net (a) $ (5.7 ) $ (5.7 ) 2.2 2.2 Tax benefit $ (3.5 ) $ (3.5 ) Net of tax Unfunded employee benefit obligations (b) Amortization of prior service costs $ (5.6 ) $ (5.5 ) Amortization of actuarial gains / (losses) (7.5 ) (5.4 ) (13.1 ) (10.9 ) Total before tax 4.9 4.2 Tax benefit $ (8.2 ) $ (6.7 ) Net of tax (a) This AOCI component is included in interest expense, net. Amount relates to the amortization of the effective portion of treasury lock derivative instruments recorded in AOCI. The net amount of settlement gains or losses on derivative instruments included in AOCI to be amortized over the next 12 months is a net loss of $5.3 million ($3.3 million after-tax). For a discussion of treasury lock derivative instrument activity, see Note 13, Derivative Instruments and Hedging Activities, for additional information. (b) These AOCI components are included in the computation of net pension and postretirement benefit costs. See Note 10, Employee Benefit Plans and Other Postretirement Benefits, for additional information.

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2017
Segment Reporting [Abstract]
Revenue from External Customers by Product Line	Segment sales to external customers by product line were as follows (dollars in millions): Year Ended December 31, 2017 2016 2015 Packaging sales Packaging sales $ 5,312.3 $ 4,584.8 $ 4,477.3 Paper White papers 1,051.8 1,065.8 1,089.6 Market pulp — 28.1 53.5 1,051.8 1,093.9 1,143.1 Corporate and Other 80.8 100.3 121.3 $ 6,444.9 $ 5,779.0 $ 5,741.7
Analysis of Operations by Reportable Segment	An analysis of operations by reportable segment is as follows (dollars in millions): Sales, net Operating Depreciation, Capital Year Ended December 31, 2017 Trade Inter- segment Total Income (Loss) Amortization, and Depletion Expenditures (k) Assets Packaging $ 5,288.6 $ 23.7 $ 5,312.3 $ 943.7 (a) $ 317.5 $ 305.1 $ 4,933.6 Paper 1,051.8 — 1,051.8 61.5 (b) 67.6 22.6 945.2 Corporate and Other 104.5 124.7 229.2 (74.0 ) (c) 6.3 15.3 318.7 Intersegment eliminations — (148.4 ) (148.4 ) — — — — $ 6,444.9 $ — $ 6,444.9 931.2 $ 391.4 $ 343.0 $ 6,197.5 Interest expense (102.6 ) (j) Income before taxes $ 828.6 Sales, net Operating Depreciation, Capital Year Ended December 31, 2016 Trade Inter- segment Total Income (Loss) Amortization, and Depletion Expenditures (k) Assets Packaging $ 4,577.4 $ 7.4 $ 4,584.8 $ 711.0 (d) $ 293.3 $ 239.9 $ 4,530.5 Paper 1,093.9 — 1,093.9 138.1 (e) 59.6 31.6 946.2 Corporate and Other 107.7 139.2 246.9 (68.9 ) (f) 5.1 2.8 300.3 Intersegment eliminations — (146.6 ) (146.6 ) — — — — $ 5,779.0 $ — $ 5,779.0 780.3 $ 358.0 $ 274.3 $ 5,777.0 Interest expense (91.8 ) Income before taxes $ 688.5 Sales, net Operating Depreciation, Capital Year Ended December 31, 2015 Trade Inter- segment Total Income (Loss) Amortization, and Depletion Expenditures (k) Assets Packaging $ 4,474.1 $ 3.2 $ 4,477.3 $ 714.9 (g) $ 297.3 $ 250.3 $ 4,027.9 Paper 1,143.1 — 1,143.1 112.5 (h) 54.9 58.5 976.5 Corporate and Other 124.5 133.8 258.3 (77.4 ) (i) 4.3 5.7 267.9 Intersegment eliminations — (137.0 ) (137.0 ) — — — — $ 5,741.7 $ — $ 5,741.7 750.0 $ 356.5 $ 314.5 $ 5,272.3 Interest expense (85.5 ) Income before taxes $ 664.5 (a) Includes the following: o $7.2 million of income, net, primarily related to the sale of land corresponding to the closure of a corrugated products facility, partially offset by closure costs related to corrugated products facilities, and a lump sum settlement of a multiemployer pension plan withdrawal liability for one of our corrugated products facilities. o $1.7 million of charges related to the Sacramento Container acquisition and integration costs related to other recent acquisitions. o $2.0 million gain related to the expiration of a repurchase option corresponding to timberland previously sold. o $1.6 million of income related to a working capital adjustment from the April 2015 sale of our Hexacomb corrugated manufacturing operations in Europe and Mexico. o $5.0 million of costs for the property damage and business interruption insurance deductible corresponding to the February 2017 explosion at our DeRidder, Louisiana mill. (b) Includes $33.4 million of charges related to our determination to discontinue production of uncoated free sheet and coated one-side grades at the Wallula, Washington mill in the second quarter of 2018 and convert the No. 3 paper machine to a high-performance 100% virgin kraft linerboard machine and $0.4 million of charges related to the closure costs of a paper administration facility. (c) Includes $1.0 million of charges related to the closure costs of a corporate administration facility and $0.7 million of income related to a working capital adjustment from the April 2015 sale of our Hexacomb corrugated manufacturing operations in Europe and Mexico. (d) Includes $10.2 million of closure costs related to corrugated product facilities and $4.2 million of acquisition-related costs for the TimBar Corporation and Columbus Container acquisitions. (e) Includes $2.7 million of costs related to ceased softwood market pulp operations at our Wallula, Washington mill and the permanent shut down of the No.1 machine and $1.7 million of closure costs related to a paper products facility. (f) Includes $0.3 million of acquisition-related costs related to the TimBar Corporation acquisition. (g) Includes net charges of $2.0 million primarily related to restructuring activities at our mill in DeRidder, Louisiana and $4.1 million of Boise acquisition integration-related and other costs. (h) In September 2015, we sold the remaining land, buildings, and equipment at our paper mill site in St. Helens, Oregon where we ceased paper production in December 2012. We recorded a $6.7 million gain on the sale. ( i ) Includes $9.3 million of Boise acquisition integration-related and other costs. These costs primarily relate to professional fees, severance, retention, relocation, travel, and other integration-related costs. (j) Includes $1.8 million of expense related to the write-off of deferred debt issuance costs in connection with the December 2017 debt refinancing. (k) Includes “Additions to property, plant, and equipment” and excludes cash used for “Acquisitions of businesses, net of cash acquired” as reported on our Consolidated Statements of Cash Flows.

Commitments, Guarantees, Inde42

Commitments, Guarantees, Indemnifications, and Legal Proceedings (Tables)	12 Months Ended
	Dec. 31, 2017
Commitments And Contingencies Disclosure [Abstract]
Schedule of Minimum Lease Payments Under Non-Cancelable Operating Leases	The minimum lease payments under non-cancelable operating leases with lease terms in excess of one year were as follows (dollars in millions): 2018 $ 63.8 2019 54.0 2020 41.1 2021 29.6 2022 19.1 Thereafter 56.2 Total $ 263.8
Schedule of Assets Held Under Capital Lease Obligations	Assets held under capital lease obligations were included in property, plant, and equipment as follows (dollars in millions): Year Ended December 31 2017 2016 Buildings $ 0.3 $ 0.3 Machinery and equipment 28.5 28.5 Total 28.8 28.8 Less accumulated amortization (15.2 ) (13.7 ) Total $ 13.6 $ 15.1
Schedule of Future Minimum Payments Under Capitalized Leases	The future minimum payments under capitalized leases at December 31, 2017 were as follows (dollars in millions): 2018 $ 2.7 2019 2.7 2020 2.7 2021 2.7 2022 2.7 Thereafter 15.0 Total minimum capital lease payments 28.5 Less amounts representing interest (8.2 ) Present value of net minimum capital lease payments 20.3 Less current maturities of capital lease obligations (1.3 ) Total long-term capital lease obligations $ 19.0
Schedule Of Purchase Commitments	Total purchase commitments were as follows (dollars in millions): 2018 $ 79.8 2019 54.4 2020 45.6 2021 43.0 2022 42.5 Thereafter 159.0 Total $ 424.3

Quarterly Results of Operatio43

Quarterly Results of Operations (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Summary of Quarterly Financial Data	2017: First (a) Second (b) Third (c) Fourth (d) Total Net sales $ 1,536.5 $ 1,584.0 $ 1,640.1 $ 1,684.3 $ 6,444.9 Gross profit 338.5 364.6 397.3 371.7 1,472.2 Income from operations 203.1 233.8 242.3 252.0 931.2 Net income 117.4 143.2 139.1 268.9 668.6 Basic earnings per share 1.25 1.52 1.47 2.85 7.09 Diluted earnings per share 1.24 1.52 1.47 2.84 7.07 Stock price - high 96.87 113.52 119.43 121.38 121.38 Stock price - low 84.01 89.73 105.81 108.49 84.01 2016: First (e) Second (f) Third (g) Fourth (h) Total Net sales $ 1,401.0 $ 1,417.4 $ 1,484.0 $ 1,476.6 $ 5,779.0 Gross profit 299.0 320.1 329.5 327.1 $ 1,275.7 Income from operations 180.8 200.2 206.4 192.9 780.3 Net income 103.7 115.9 119.4 110.6 449.6 Basic earnings per share 1.09 1.23 1.27 1.17 4.76 Diluted earnings per share 1.09 1.23 1.26 1.17 4.75 Stock price - high 62.67 71.31 82.77 88.41 88.41 Stock price - low 44.32 58.44 65.12 78.03 44.32 Note: The sum of the quarters may not equal the total of the respective year's earnings per share on either a basic or diluted basis due to changes in the weighted average shares outstanding throughout the year. (a) Includes $0.6 million of charges related to the closure of corrugated products facilities and lump sum settlement of a multiemployer pension plan withdrawal liability for one of corrugated products facilities ($0.4 million after-tax or $0.1 per diluted share) and $0.2 million of charges related to TimBar Corporation and Columbus Container integration costs ($0.1 million after-tax or $0.0 per diluted share). Also includes $5.0 million of costs for the property damage and business interruption insurance deductible corresponding to the February 2017 explosion at our DeRidder, Louisiana mill ($3.1 million after-tax or $0.03 per diluted share) and $2.3 million of income related to a working capital adjustment from the April 2015 sale of our Hexacomb corrugated manufacturing operations in Europe and Mexico ($1.4 million after-tax or $0.01 per diluted share). (b) Includes $0.3 million of charges related to the closure of corrugated products facilities ($0.3 million after-tax or $0.0 per diluted share) and $0.2 million of charges related to TimBar Corporation and Columbus Container integration costs ($0.1 after-tax or $0.0 per diluted share). (c) Includes $0.9 million of charges related to the closure of corrugated products facilities, a paper administration facility, and a lump sum settlement of a multiemployer pension plan withdrawal liability for one of our corrugated products facilities ($0.6 million after-tax or $0.01 per diluted share) and $0.5 million of charges related to the Sacramento Container acquisition and integration costs related to other recent acquisitions ($0.3 million after-tax or $0.0 per diluted share). Also includes $25.3 million of charges related to our determination to discontinue production of uncoated free sheet and coated one-side grades at the Wallula, Washington mill in the second quarter of 2018 and convert the No. 3 paper machine to a high-performance 100% virgin kraft linerboard machine ($15.5 million after-tax or $0.16 per diluted share) and $3.3 million of tax expense for the change in value of deferred taxes as a result of an internal legal entity consolidation that will simplify future operating activities ($0.04 per diluted share). (d) Includes $7.6 million of income primarily related to the sale of land corresponding to the closure of a corrugated products facility, partially offset by closure costs related to corrugated products facilities, a paper administration facility, and a corporate administration facility ($4.7 million after-tax or $0.05 per diluted share) and $0.9 million of charges related to the Sacramento Container acquisition and integration costs related to other recent acquisitions ($0.5 million after-tax or $0.01 per diluted share), and $8.0 million of charges related to our determination to discontinue production of uncoated free sheet and coated one-side grades at the Wallula, Washington mill in the second quarter of 2018 and convert the No. 3 paper machine to a high-performance 100% virgin kraft linerboard machine ($4.6 million after-tax or $0.05 per diluted share). Also includes $1.8 million of expense related to the write-off of deferred debt issuance costs in connection with the December 2017 debt refinancing ($1.1 million after-tax or $0.01 per diluted share), $2.0 million gain related to the expiration of a repurchase option corresponding to timberland previously sold ($1.2 million after-tax or 0.01 per diluted share), and $122.1 million of estimated income tax benefit related to the enactment in December 2017 of the Tax Cuts and Jobs Act (H.R.1) primarily for the re-measurement of our net deferred tax liability as a result of the reduction in the U.S. corporate income tax rate ($1.29 per diluted share). (e) Includes $2.8 million of charges related to the closure of a corrugated products facility and a paper products facility ($1.9 million after-tax or $0.02 per diluted share). (f) Includes $2.6 million of charges related to the closure of corrugated products facilities, a paper products facility, and a lump sum settlement of a multiemployer pension plan withdrawal liability for one of our corrugated products facilities ($1.6 million after-tax or $0.02 per diluted share) and $0.3 million of charges related to the TimBar Corporation acquisition and integration ($0.2 million after-tax or $0.0 per diluted share). (g) Includes $2.0 million of charges related to the closure of a corrugated products facility and a paper products facility ($1.4 million after-tax or $0.02 per diluted share) and $2.9 million of charges related to the TimBar Corporation and Columbus Container acquisitions and integration ($1.9 million after-tax or $0.02 per diluted share). (h) Includes $4.5 million of charges related to the closure of a corrugated products facility and a paper products facility ($2.9 million after-tax or $0.03 per diluted share), $2.7 million of costs related to ceased production of softwood market pulp operations at our Wallula, Washington mill and the permanent shutdown of the No. 1 machine ($1.8 million after-tax or $0.02 per diluted share), and $1.2 million of charges related to the TimBar Corporation and Columbus Container acquisitions and integration ($0.8 million after-tax or $0.01 per diluted share).

Nature of Operations and Basi44

Nature of Operations and Basis of Presentation - Additional Information (Details)	3 Months Ended	12 Months Ended
	Jun. 30, 2018T	Dec. 31, 2017employeeSegment
New Accounting Pronouncement Early Adoption [Line Items]
Date of incorporation		Jan. 25, 1999
Number of employees of PCA | employee		14,600
Number of reportable segments | Segment		3
Virgin Kraft Linerboard Machine | Scenario, Forecast
New Accounting Pronouncement Early Adoption [Line Items]
Production capacity of machine per year | T	400,000

Summary of Significant Accoun45

Summary of Significant Accounting Policies - Additional Information (Details)	12 Months Ended
	Dec. 31, 2017USD ($)a	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Summary of Significant Accounting Policies [Line Items]
Research and development costs	$ 12,800,000	$ 13,300,000	$ 13,100,000
Cash and cash equivalents	216,900,000	239,300,000	184,200,000	$ 124,900,000
Cash equivalents	160,200,000	178,400,000
Allowance for doubtful accounts	$ 4,200,000	3,800,000
Customer returns, allowances and earned discounts as a percentage of gross selling price	1.00%
Reserve for customer accounts receivable, percentage	1.00%
Reserve for customer deductions	$ 8,400,000	6,300,000
Interest capitalization, construction in progress	$ 2,500,000	$ 2,500,000	2,000,000
Intangible asset, useful life, in years	11 years 8 months 12 days	12 years 10 months 24 days
Goodwill	$ 883,200,000	$ 737,900,000	544,000,000
Goodwill and intangible asset impairment	0	0	0
Deferred financing costs	$ 15,300,000	12,500,000
Area leased under timberland cutting rights (acres) | a	75,000
Area leased where fiber farms are operated (acres) | a	9,000
Depletion expense	$ 5,200,000	4,700,000	7,000,000
Impairment loss	(13,500,000)
Software amortization expense	2,300,000	2,500,000	$ 3,000,000
Unrecognized excess tax benefits	4,200,000
Other long-term assets
Summary of Significant Accounting Policies [Line Items]
Long-term lease costs capitalization (Cutting rights and Fiber farms)	31,500,000	43,900,000
Net capitalized software costs	3,300,000	4,500,000
Adjustments for New Accounting Pronouncement | Long-term debt
Summary of Significant Accounting Policies [Line Items]
Deferred financing costs		$ 12,400,000
ASU 2014-09 | Customers Under Consignment Agreement
Summary of Significant Accounting Policies [Line Items]
Cumulative impact of opening retained earnings, net of tax	1,600,000
ASU 2016-09
Summary of Significant Accounting Policies [Line Items]
Excess tax benefits from share-based compensation	6,800,000
Unrecognized excess tax benefits	$ 0
Customer Relationships
Summary of Significant Accounting Policies [Line Items]
Intangible asset, useful life, in years	11 years 9 months 18 days	13 years 1 month 6 days
Trademarks and Trade Names
Summary of Significant Accounting Policies [Line Items]
Intangible asset, useful life, in years	9 years 9 months 18 days	10 years 6 months
Minimum
Summary of Significant Accounting Policies [Line Items]
Term of senior credit facilities and notes, in years	5 years
Minimum | Adjustments for New Accounting Pronouncement | Long-term debt
Summary of Significant Accounting Policies [Line Items]
Deferred financing costs	$ 15,300,000
Minimum | Customer Relationships
Summary of Significant Accounting Policies [Line Items]
Intangible asset, useful life, in years	10 years
Minimum | Trademarks and Trade Names
Summary of Significant Accounting Policies [Line Items]
Intangible asset, useful life, in years	2 years
Maximum
Summary of Significant Accounting Policies [Line Items]
Term of senior credit facilities and notes, in years	10 years
Maximum | Customer Relationships
Summary of Significant Accounting Policies [Line Items]
Intangible asset, useful life, in years	40 years
Maximum | Trademarks and Trade Names
Summary of Significant Accounting Policies [Line Items]
Intangible asset, useful life, in years	20 years
Foreign operations
Summary of Significant Accounting Policies [Line Items]
Cash and cash equivalents	$ 1,800,000	$ 3,400,000

Summary of Significant Accoun46

Summary of Significant Accounting Policies - Components of Inventories (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Inventory Disclosure [Abstract]
Raw materials	$ 279.8	$ 271.9
Work in process	12.6	12.9
Finished goods	217	206.5
Supplies and materials	253.1	232.3
Inventories	$ 762.5	$ 723.6

Summary of Significant Accoun47

Summary of Significant Accounting Policies - Property, Plant and Equipment (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property Plant And Equipment [Line Items]
Property, plant and equipment, at cost	$ 6,311.2		$ 6,311.2	$ 6,010.3
Less accumulated depreciation	(3,386.3)		(3,386.3)	(3,114.6)
Property, plant and equipment, net	$ 2,924.9		2,924.9	2,895.7
Depreciation [Abstract]
Depreciation expense			347.8	324.1	$ 323
Incremental depreciation			$ 10.5	2.9	$ 9
Wallula, Washington Mill
Depreciation [Abstract]
High-performance of virgin kraft linerboard machine percentage	100.00%	100.00%	100.00%
Land and Land Improvements
Property Plant And Equipment [Line Items]
Property, plant and equipment, at cost	$ 156		$ 156	149.7
Buildings
Property Plant And Equipment [Line Items]
Property, plant and equipment, at cost	729.8		729.8	717.1
Machinery and Equipment
Property Plant And Equipment [Line Items]
Property, plant and equipment, at cost	5,162.5		5,162.5	4,951.4
Construction in Progress
Property Plant And Equipment [Line Items]
Property, plant and equipment, at cost	194.5		194.5	125.4
Other
Property Plant And Equipment [Line Items]
Property, plant and equipment, at cost	$ 68.4		$ 68.4	$ 66.7

Summary of Significant Accoun48

Summary of Significant Accounting Policies - Estimated Useful Lives of Assets (Details)	12 Months Ended
	Dec. 31, 2017
Leasehold Improvements
Property Plant And Equipment [Line Items]
Estimated useful life of asset, description	Period of the lease or useful life, if shorter
Minimum | Buildings And Land Improvements
Property Plant And Equipment [Line Items]
Estimated useful life of asset (in years)	5 years
Minimum | Machinery and Equipment
Property Plant And Equipment [Line Items]
Estimated useful life of asset (in years)	3 years
Minimum | Trucks and Automobiles
Property Plant And Equipment [Line Items]
Estimated useful life of asset (in years)	3 years
Minimum | Furniture and Fixtures
Property Plant And Equipment [Line Items]
Estimated useful life of asset (in years)	3 years
Minimum | Computers and Hardware
Property Plant And Equipment [Line Items]
Estimated useful life of asset (in years)	3 years
Maximum | Buildings And Land Improvements
Property Plant And Equipment [Line Items]
Estimated useful life of asset (in years)	40 years
Maximum | Machinery and Equipment
Property Plant And Equipment [Line Items]
Estimated useful life of asset (in years)	25 years
Maximum | Trucks and Automobiles
Property Plant And Equipment [Line Items]
Estimated useful life of asset (in years)	10 years
Maximum | Furniture and Fixtures
Property Plant And Equipment [Line Items]
Estimated useful life of asset (in years)	20 years
Maximum | Computers and Hardware
Property Plant And Equipment [Line Items]
Estimated useful life of asset (in years)	10 years

Acquisitions and Dispositions -

Acquisitions and Dispositions - Additional Information (Details) $ in Millions

Oct. 02, 2017USD ($)

Aug. 29, 2016USD ($)facility

Nov. 30, 2016USD ($)facility

Dec. 31, 2017USD ($)

Dec. 31, 2017USD ($)

[1]

Sep. 30, 2017USD ($)

Jun. 30, 2017USD ($)

[3]

Mar. 31, 2017USD ($)

Dec. 31, 2016USD ($)

[5]

Sep. 30, 2016USD ($)

[6]

Jun. 30, 2016USD ($)

[7]

Mar. 31, 2016USD ($)

[8]

Dec. 31, 2017USD ($)

Dec. 31, 2016USD ($)

Dec. 31, 2015USD ($)

Business Acquisition [Line Items]

Cash purchase price

$ 273.8

$ 485.4

Net sales

$ 1,684.3

$ 1,640.1

[2]

$ 1,584

$ 1,536.5

[4]

$ 1,476.6

$ 1,484

$ 1,417.4

$ 1,401

6,444.9

5,779

$ 5,741.7

Sacramento Container Corporation

Business Acquisition [Line Items]

Acquisition completion date

Oct. 2, 2017

Cash purchase price

$ 265

Net sales

$ 58.5

Percentage of net sales

1.00%

Proforma net sales

$ 6,600

$ 6,000

Working capital adjustment on purchase price

8.8

Increase to other net assets acquired, acquisition adjustment

$ 8.8

$ 8.8

Maximum Acquisition period to finalize valuation

12 months

Acquired finite-lived intangible assets, weighted average useful life

9 years 8 months 12 days

Northern Sheets LLC And Central California Sheets LLC

Business Acquisition [Line Items]

Percentage of membership interests acquired

100.00%

Columbus Container Inc

Business Acquisition [Line Items]

Cash purchase price

$ 99.7

Working capital adjustment on purchase price

2.2

Increase to other net assets acquired, acquisition adjustment

(0.1)

Acquired finite-lived intangible assets, weighted average useful life

14 years 1 month 6 days

Number of corrugated products production facilities acquired | facility

1

Number of corrugated products warehousing facilities acquired | facility

5

Increase to goodwill, acquisition adjustment

$ 2.2

(4.7)

TimBar Corporation

Business Acquisition [Line Items]

Cash purchase price

$ 385.6

Working capital adjustment on purchase price

(1.1)

Acquired finite-lived intangible assets, weighted average useful life

14 years 2 months 12 days

Number of corrugated products production facilities acquired | facility

6

Increase to goodwill, acquisition adjustment

$ (1.1)

Debt instrument, face amount

$ 385

Debt instrument, term

5 years

Purchase price

$ 384.5

Minimum | Sacramento Container Corporation

Business Acquisition [Line Items]

Property, plant and equipment useful life

1 year

Minimum | Columbus Container Inc

Business Acquisition [Line Items]

Property, plant and equipment useful life

1 year

Minimum | TimBar Corporation

Business Acquisition [Line Items]

Property, plant and equipment useful life

2 years

Maximum | Sacramento Container Corporation

Business Acquisition [Line Items]

Property, plant and equipment useful life

13 years

Maximum | Columbus Container Inc

Business Acquisition [Line Items]

Property, plant and equipment useful life

32 years

Maximum | TimBar Corporation

Business Acquisition [Line Items]

Property, plant and equipment useful life

24 years

[1]

Includes $7.6 million of income primarily related to the sale of land corresponding to the closure of a corrugated products facility, partially offset by closure costs related to corrugated products facilities, a paper administration facility, and a corporate administration facility ($4.7 million after-tax or $0.05 per diluted share) and $0.9 million of charges related to the Sacramento Container acquisition and integration costs related to other recent acquisitions ($0.5 million after-tax or $0.01 per diluted share), and $8.0 million of charges related to our determination to discontinue production of uncoated free sheet and coated one-side grades at the Wallula, Washington mill in the second quarter of 2018 and convert the No. 3 paper machine to a high-performance 100% virgin kraft linerboard machine ($4.6 million after-tax or $0.05 per diluted share). Also includes $1.8 million of expense related to the write-off of deferred debt issuance costs in connection with the December 2017 debt refinancing ($1.1 million after-tax or $0.01 per diluted share), $2.0 million gain related to the expiration of a repurchase option corresponding to timberland previously sold ($1.2 million after-tax or 0.01 per diluted share), and $122.1 million of estimated income tax benefit related to the enactment in December 2017 of the Tax Cuts and Jobs Act (H.R.1) primarily for the re-measurement of our net deferred tax liability as a result of the reduction in the U.S. corporate income tax rate ($1.29 per diluted share).

[2]

Includes $0.9 million of charges related to the closure of corrugated products facilities, a paper administration facility, and a lump sum settlement of a multiemployer pension plan withdrawal liability for one of our corrugated products facilities ($0.6 million after-tax or $0.01 per diluted share) and $0.5 million of charges related to the Sacramento Container acquisition and integration costs related to other recent acquisitions ($0.3 million after-tax or $0.0 per diluted share). Also includes $25.3 million of charges related to our determination to discontinue production of uncoated free sheet and coated one-side grades at the Wallula, Washington mill in the second quarter of 2018 and convert the No. 3 paper machine to a high-performance 100% virgin kraft linerboard machine ($15.5 million after-tax or $0.16 per diluted share) and $3.3 million of tax expense for the change in value of deferred taxes as a result of an internal legal entity consolidation that will simplify future operating activities ($0.04 per diluted share).

[3]

Includes $0.3 million of charges related to the closure of corrugated products facilities ($0.3 million after-tax or $0.0 per diluted share) and $0.2 million of charges related to TimBar Corporation and Columbus Container integration costs ($0.1 after-tax or $0.0 per diluted share).

[4]

Includes $0.6 million of charges related to the closure of corrugated products facilities and lump sum settlement of a multiemployer pension plan withdrawal liability for one of corrugated products facilities ($0.4 million after-tax or $0.1 per diluted share) and $0.2 million of charges related to TimBar Corporation and Columbus Container integration costs ($0.1 million after-tax or $0.0 per diluted share). Also includes $5.0 million of costs for the property damage and business interruption insurance deductible corresponding to the February 2017 explosion at our DeRidder, Louisiana mill ($3.1 million after-tax or $0.03 per diluted share) and $2.3 million of income related to a working capital adjustment from the April 2015 sale of our Hexacomb corrugated manufacturing operations in Europe and Mexico ($1.4 million after-tax or $0.01 per diluted share).

[5]

Includes $4.5 million of charges related to the closure of a corrugated products facility and a paper products facility ($2.9 million after-tax or $0.03 per diluted share), $2.7 million of costs related to ceased production of softwood market pulp operations at our Wallula, Washington mill and the permanent shutdown of the No. 1 machine ($1.8 million after-tax or $0.02 per diluted share), and $1.2 million of charges related to the TimBar Corporation and Columbus Container acquisitions and integration ($0.8 million after-tax or $0.01 per diluted share).

[6]

Includes $2.0 million of charges related to the closure of a corrugated products facility and a paper products facility ($1.4 million after-tax or $0.02 per diluted share) and $2.9 million of charges related to the TimBar Corporation and Columbus Container acquisitions and integration ($1.9 million after-tax or $0.02 per diluted share).

[7]

Includes $2.6 million of charges related to the closure of corrugated products facilities, a paper products facility, and a lump sum settlement of a multiemployer pension plan withdrawal liability for one of our corrugated products facilities ($1.6 million after-tax or $0.02 per diluted share) and $0.3 million of charges related to the TimBar Corporation acquisition and integration ($0.2 million after-tax or $0.0 per diluted share).

[8]

Includes $2.8 million of charges related to the closure of a corrugated products facility and a paper products facility ($1.9 million after-tax or $0.02 per diluted share).

Acquisitions and Dispositions50

Acquisitions and Dispositions - Schedule of Acquisitions (Details) - USD ($) $ in Millions	Oct. 02, 2017	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Goodwill		$ 883.2		$ 883.2	$ 737.9	$ 544
Packaging
Business Acquisition [Line Items]
Goodwill		828		828	682.7	$ 488.8
Sacramento Container Corporation
Business Acquisition [Line Items]
Other intangible assets	$ 72.6	72.6		72.6
Property, plant and equipment	26.7	26.7		26.7
Other net assets	14.6	23.4		23.4
Net assets acquired	265	273.8		273.8
Other net assets, Adjustments	8.8	8.8
Net assets acquired, Adjustments		8.8
Sacramento Container Corporation | Packaging
Business Acquisition [Line Items]
Goodwill	$ 151.1	151.1		151.1
Columbus Container Inc
Business Acquisition [Line Items]
Other intangible assets		32.3		32.3	26.3
Property, plant and equipment		28.2		28.2	27.2
Other net assets		9.5		9.5	9.6
Net assets acquired		101.9		101.9	99.7
Goodwill, Adjustments			$ 2.2	(4.7)
Other intangible assets, Adjustments				6
Property, plant and equipment, Adjustments				1
Other net assets, Adjustments				(0.1)
Net assets acquired, Adjustments				2.2
Columbus Container Inc | Packaging
Business Acquisition [Line Items]
Goodwill		31.9		31.9	36.6
TimBar Corporation
Business Acquisition [Line Items]
Other intangible assets		94.4		94.4	94.4
Property, plant and equipment		95.3		95.3	95.3
Other net assets		38.6		38.6	38.6
Net assets acquired		384.5		384.5	385.6
Goodwill, Adjustments				(1.1)
Net assets acquired, Adjustments				(1.1)
TimBar Corporation | Packaging
Business Acquisition [Line Items]
Goodwill		$ 156.2		$ 156.2	$ 157.3

Earnings Per Share - Computatio

Earnings Per Share - Computation of Basic and Diluted Income Per Common Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended																12 Months Ended
	Dec. 31, 2017	[1]	Sep. 30, 2017	[2]	Jun. 30, 2017	[3]	Mar. 31, 2017	[4]	Dec. 31, 2016	[5]	Sep. 30, 2016	[6]	Jun. 30, 2016	[7]	Mar. 31, 2016	[8]	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Numerator:
Net income	$ 268.9		$ 139.1		$ 143.2		$ 117.4		$ 110.6		$ 119.4		$ 115.9		$ 103.7		$ 668.6	$ 449.6	$ 436.8
Less: distributed and undistributed earnings allocated to participating securities																	(5.6)	(4.4)	(5.2)
Net income attributable to common stockholders																	$ 663	$ 445.2	$ 431.6
Denominator:
Weighted average common shares outstanding																	93.5	93.5	96.6
Effect of dilutive securities (in shares)																	0.2	0.2	0.1
Diluted common shares outstanding																	93.7	93.7	96.7
Basic income per common share (in dollars per share)	$ 2.85		$ 1.47		$ 1.52		$ 1.25		$ 1.17		$ 1.27		$ 1.23		$ 1.09		$ 7.09	$ 4.76	$ 4.47
Diluted income per common share (in dollars per share)	$ 2.84		$ 1.47		$ 1.52		$ 1.24		$ 1.17		$ 1.26		$ 1.23		$ 1.09		$ 7.07	$ 4.75	$ 4.47
[1]	Includes $7.6 million of income primarily related to the sale of land corresponding to the closure of a corrugated products facility, partially offset by closure costs related to corrugated products facilities, a paper administration facility, and a corporate administration facility ($4.7 million after-tax or $0.05 per diluted share) and $0.9 million of charges related to the Sacramento Container acquisition and integration costs related to other recent acquisitions ($0.5 million after-tax or $0.01 per diluted share), and $8.0 million of charges related to our determination to discontinue production of uncoated free sheet and coated one-side grades at the Wallula, Washington mill in the second quarter of 2018 and convert the No. 3 paper machine to a high-performance 100% virgin kraft linerboard machine ($4.6 million after-tax or $0.05 per diluted share). Also includes $1.8 million of expense related to the write-off of deferred debt issuance costs in connection with the December 2017 debt refinancing ($1.1 million after-tax or $0.01 per diluted share), $2.0 million gain related to the expiration of a repurchase option corresponding to timberland previously sold ($1.2 million after-tax or 0.01 per diluted share), and $122.1 million of estimated income tax benefit related to the enactment in December 2017 of the Tax Cuts and Jobs Act (H.R.1) primarily for the re-measurement of our net deferred tax liability as a result of the reduction in the U.S. corporate income tax rate ($1.29 per diluted share).
[2]	Includes $0.9 million of charges related to the closure of corrugated products facilities, a paper administration facility, and a lump sum settlement of a multiemployer pension plan withdrawal liability for one of our corrugated products facilities ($0.6 million after-tax or $0.01 per diluted share) and $0.5 million of charges related to the Sacramento Container acquisition and integration costs related to other recent acquisitions ($0.3 million after-tax or $0.0 per diluted share). Also includes $25.3 million of charges related to our determination to discontinue production of uncoated free sheet and coated one-side grades at the Wallula, Washington mill in the second quarter of 2018 and convert the No. 3 paper machine to a high-performance 100% virgin kraft linerboard machine ($15.5 million after-tax or $0.16 per diluted share) and $3.3 million of tax expense for the change in value of deferred taxes as a result of an internal legal entity consolidation that will simplify future operating activities ($0.04 per diluted share).
[3]	Includes $0.3 million of charges related to the closure of corrugated products facilities ($0.3 million after-tax or $0.0 per diluted share) and $0.2 million of charges related to TimBar Corporation and Columbus Container integration costs ($0.1 after-tax or $0.0 per diluted share).
[4]	Includes $0.6 million of charges related to the closure of corrugated products facilities and lump sum settlement of a multiemployer pension plan withdrawal liability for one of corrugated products facilities ($0.4 million after-tax or $0.1 per diluted share) and $0.2 million of charges related to TimBar Corporation and Columbus Container integration costs ($0.1 million after-tax or $0.0 per diluted share). Also includes $5.0 million of costs for the property damage and business interruption insurance deductible corresponding to the February 2017 explosion at our DeRidder, Louisiana mill ($3.1 million after-tax or $0.03 per diluted share) and $2.3 million of income related to a working capital adjustment from the April 2015 sale of our Hexacomb corrugated manufacturing operations in Europe and Mexico ($1.4 million after-tax or $0.01 per diluted share).
[5]	Includes $4.5 million of charges related to the closure of a corrugated products facility and a paper products facility ($2.9 million after-tax or $0.03 per diluted share), $2.7 million of costs related to ceased production of softwood market pulp operations at our Wallula, Washington mill and the permanent shutdown of the No. 1 machine ($1.8 million after-tax or $0.02 per diluted share), and $1.2 million of charges related to the TimBar Corporation and Columbus Container acquisitions and integration ($0.8 million after-tax or $0.01 per diluted share).
[6]	Includes $2.0 million of charges related to the closure of a corrugated products facility and a paper products facility ($1.4 million after-tax or $0.02 per diluted share) and $2.9 million of charges related to the TimBar Corporation and Columbus Container acquisitions and integration ($1.9 million after-tax or $0.02 per diluted share).
[7]	Includes $2.6 million of charges related to the closure of corrugated products facilities, a paper products facility, and a lump sum settlement of a multiemployer pension plan withdrawal liability for one of our corrugated products facilities ($1.6 million after-tax or $0.02 per diluted share) and $0.3 million of charges related to the TimBar Corporation acquisition and integration ($0.2 million after-tax or $0.0 per diluted share).
[8]	Includes $2.8 million of charges related to the closure of a corrugated products facility and a paper products facility ($1.9 million after-tax or $0.02 per diluted share).

Other Expense, Net (Details)

Other Expense, Net (Details) - USD ($) $ in Millions		1 Months Ended	12 Months Ended
		Sep. 30, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Asset disposals and write-offs			$ (10.5)	$ (11.9)	$ (14)
Acquisition and integration related costs	[1],[2],[3]		(0.8)	(3.3)	(12.9)
Expiration of timberland repurchase option	[4]		2
Hexacomb working capital adjustment	[5]		2.3
Facilities closure and other costs	[6]		5.9	(10.3)
Refundable state tax credit	[7]				3.6
Other			3.9	(1.8)	(2.8)
Total			(18.4)	(24.3)	(6.7)
Wallula, Washington Mill
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Restructuring	[8]		(23.1)
Ceased production of market pulp at Wallula	[9]			$ (0.6)
Deridder Mill
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Restructuring	[10]				7.1
DeRidder mill incident	[11]		$ 9.7
Mill at St. Helens, Oregon
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sale of St. Helens Paper Mill Site		$ 6.7			$ 6.7	[12]
[1]	For 2015, includes Boise acquisition integration-related and other costs, which primarily relate to severance, retention, travel, and professional fees.
[2]	For 2016, includes charges related to the acquisition and integration of TimBar Corporation.
[3]	For 2017, includes charges related to the Sacramento Container Corporation acquisition and integration costs related to other recent acquisitions.
[4]	Includes a gain related to the expiration of a repurchase option corresponding to timberland previously sold.
[5]	Includes income related to a working capital adjustment from the April 2015 sale of our Hexacomb corrugated manufacturing operations in Europe and Mexico.
[6]	For 2017, includes income primarily related to the sale of land corresponding to the closure of a corrugated products facility, partially offset by closure costs related to corrugated products facilities, a paper administration facility, a corporate administration facility, and a lump sum settlement of a multiemployer pension plan withdrawal liability for one of our corrugated products facilities. For 2016, includes expenses related to the closure of corrugated products facilities and a paper administration facility and a lump sum settlement of a multiemployer pension plan withdrawal liability for one of our corrugated products facilities.
[7]	Includes a tax credit from the State of Louisiana related to capital investment and the jobs retained at the DeRidder, Louisiana mill.
[8]	Includes $23.1 million of charges related to our determination to discontinue production of uncoated free sheet and coated one-side grades at the Wallula, Washington mill in the second quarter of 2018 and convert the No. 3 paper machine to a high-performance 100% virgin kraft linerboard machine.
[9]	Includes costs related to ceased softwood market pulp operations at our Wallula, Washington mill and the permanent shutdown of the No. 1 machine.
[10]	Includes $7.1 million of income from vendor settlements related to our restructuring activities at our DeRidder, Louisiana mill.
[11]	Includes the property damage and business interruption insurance recoveries and corresponding costs related to the February 2017 explosion at our DeRidder, Louisiana mill.
[12]	Includes a gain related to the sale of the remaining land, buildings, and equipment at our paper mill site in St. Helens, Oregon where we ceased paper production in December 2012.

Other (Expense), Net (Parenthet

Other (Expense), Net (Parentheticals) (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2015
Wallula, Washington Mill
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Restructuring charges			$ 23.1
High-performance of virgin kraft linerboard machine percentage	100.00%	100.00%	100.00%
Deridder Mill
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income from vendor settlements				$ 7.1

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Taxes [Line Items]
Federal corporate tax rate		35.00%	35.00%	35.00%
Maximum measurement period to finalize accounting of tax		1 year
Income tax benefit as result of Tax Act		$ 122.1
Re-measurement of deferred tax assets and liabilities due to enacted corporate tax rate		128
Reduction in domestic manufacturers deductions		5.1
Transition tax due to tax reform		0.8
Increase in deferred tax liabilities		24.6
Provisional transition tax obligation		0.1
Cash payments for income taxes		298.7	$ 222.1	$ 238.3
Gross reserve for unrecognized tax benefits, excluding interest and penalties		4.8	5.2	$ 5.8	$ 4.4
Unrecognized tax benefits that would impact of effective tax rate		4.2
Interest accrued related to unrecognized tax benefits and penalties		1.1	$ 1.1
Reasonably possible decrease in unrecognized tax benefits related to state apportionment issues in next 12 months		$ 3.1
Internal Revenue Service (IRS)
Income Taxes [Line Items]
Income tax examination (description)		A federal examination of the tax years 2010 - 2012 was concluded in February 2015
Foreign
Income Taxes [Line Items]
Open tax year		2,009
Boise Inc.
Income Taxes [Line Items]
Open tax year		2,013
Earliest Tax Year | Internal Revenue Service (IRS)
Income Taxes [Line Items]
Open tax year		2,014
Earliest Tax Year | State taxing jurisdiction
Income Taxes [Line Items]
Open tax year		2,013
Earliest Tax Year | Boise Inc.
Income Taxes [Line Items]
Open tax year		2,008
Latest Tax Year | Internal Revenue Service (IRS)
Income Taxes [Line Items]
Open tax year		2,017
Latest Tax Year | State taxing jurisdiction
Income Taxes [Line Items]
Open tax year		2,017
Latest Tax Year | Boise Inc.
Income Taxes [Line Items]
Open tax year		2,011
Minimum
Income Taxes [Line Items]
Estimated federal and state effective tax rate		0.24
Maximum
Income Taxes [Line Items]
Estimated federal and state effective tax rate		0.26
Scenario, Forecast
Income Taxes [Line Items]
Federal corporate tax rate	21.00%

Income Taxes - Components of Co

Income Taxes - Components of Consolidated Income Tax Provision (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current income tax provision (benefit) -
U.S. federal	$ 209.3	$ 213.6	$ 205.1
State and local	34.9	29.1	20.5
Foreign	0.3	0.2	0.4
Total current provision for taxes	244.5	242.9	226
Deferred -
U.S. federal	(90.2)	(1.2)	(3.8)
State and local	5.7	(3)	5.6
Foreign		0.2	(0.1)
Total deferred provision (benefit) for taxes	(84.5)	(4)	1.7
Total provision (benefit) for taxes	$ 160	$ 238.9	$ 227.7

Income Taxes - Summary of Effec

Income Taxes - Summary of Effective Tax Rate (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Provision computed at U.S. federal statutory rate of 35%	$ 290	$ 241	$ 232.6
Federal tax reform	(127.2)
State and local taxes, net of federal benefit	24	19.8	20
Domestic manufacturers deduction	(21.1)	(21.1)	(19.9)
Other	(5.7)	(0.8)	(5)
Total provision (benefit) for taxes	$ 160	$ 238.9	$ 227.7

Income Taxes - Summary of Eff57

Income Taxes - Summary of Effective Tax Rate (Parenthetical) (Details)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
U.S. Federal statutory rate	35.00%	35.00%	35.00%

Income Taxes - Details of Sched

Income Taxes - Details of Scheduled Expiration Dates of Tax Effected Net Operating Loss (NOL) and Other Tax Carryforwards (Details) $ in Millions	Dec. 31, 2017USD ($)
Operating Loss Carryforwards And Other Tax Carryforwards [Line Items]
Total	$ 41.3
U.S. federal
Operating Loss Carryforwards And Other Tax Carryforwards [Line Items]
Net Operating Loss	35.8
U.S. federal tax credit carryforwards	0.1
State taxing jurisdiction
Operating Loss Carryforwards And Other Tax Carryforwards [Line Items]
Net Operating Loss	2.3
U.S. federal and non-U.S.
Operating Loss Carryforwards And Other Tax Carryforwards [Line Items]
U.S. federal and non-U.S. capital loss carryforwards	3.1
2018 Through 2027
Operating Loss Carryforwards And Other Tax Carryforwards [Line Items]
Total	4.4
2018 Through 2027 | U.S. federal
Operating Loss Carryforwards And Other Tax Carryforwards [Line Items]
Net Operating Loss	0
U.S. federal tax credit carryforwards	0
2018 Through 2027 | State taxing jurisdiction
Operating Loss Carryforwards And Other Tax Carryforwards [Line Items]
Net Operating Loss	1.4
2018 Through 2027 | U.S. federal and non-U.S.
Operating Loss Carryforwards And Other Tax Carryforwards [Line Items]
U.S. federal and non-U.S. capital loss carryforwards	3
2028 Through 2037
Operating Loss Carryforwards And Other Tax Carryforwards [Line Items]
Total	36.8
2028 Through 2037 | U.S. federal
Operating Loss Carryforwards And Other Tax Carryforwards [Line Items]
Net Operating Loss	35.8
U.S. federal tax credit carryforwards	0.1
2028 Through 2037 | State taxing jurisdiction
Operating Loss Carryforwards And Other Tax Carryforwards [Line Items]
Net Operating Loss	0.9
2028 Through 2037 | U.S. federal and non-U.S.
Operating Loss Carryforwards And Other Tax Carryforwards [Line Items]
U.S. federal and non-U.S. capital loss carryforwards	0
Indefinite
Operating Loss Carryforwards And Other Tax Carryforwards [Line Items]
Total	0.1
Indefinite | U.S. federal
Operating Loss Carryforwards And Other Tax Carryforwards [Line Items]
Net Operating Loss	0
U.S. federal tax credit carryforwards	0
Indefinite | State taxing jurisdiction
Operating Loss Carryforwards And Other Tax Carryforwards [Line Items]
Net Operating Loss	0
Indefinite | U.S. federal and non-U.S.
Operating Loss Carryforwards And Other Tax Carryforwards [Line Items]
U.S. federal and non-U.S. capital loss carryforwards	$ 0.1

Income Taxes - Deferred Income

Income Taxes - Deferred Income Tax Assets and Liabilities (Details) - USD ($) $ in Millions		Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
Accrued liabilities		$ 13.7	$ 18.1
Employee benefits and compensation		21.1	45.9
Inventories		15.4	9.9
Net operating loss carryforwards		38.1	67.4
Restricted stock and performance units		9	11.7
Pension and postretirement benefits		90.6	136.5
Derivatives		6.1	11.5
Capital loss and general business credit carryforwards		3.2	5.3
Gross deferred tax assets		197.2	306.3
Valuation allowance	[1]	(3.1)	(5.2)
Net deferred tax assets		194.1	301.1
Deferred tax liabilities:
Property, plant and equipment		(368.6)	(537)
Goodwill and intangible assets		(65)	(98.8)
Total deferred tax liabilities		(433.6)	(635.8)
Net deferred tax liabilities	[2]	$ (239.5)	$ (334.7)
[1]	Deferred tax assets are reduced by a valuation allowance when it is more likely than not that some portion of the deferred tax assets will not be realized. Both the 2017 and 2016 valuation allowance relates to capital losses. We do not expect to generate capital gains before the capital losses expire. If or when recognized, the tax benefits relating to the reversal of any or all of the valuation allowance would be recognized as a benefit to income tax expense.
[2]	As of December 31, 2017, we did not recognize U.S. deferred income taxes on our cumulative total of undistributed foreign earnings for our foreign subsidiaries. We indefinitely reinvest our earnings in operations outside the United States. It is not practicable to determine the amount of unrecognized deferred tax liability on these undistributed earnings because the actual tax liability, if any, is dependent on circumstances existing when the repatriation occurs.

Income Taxes - Summary of Chang

Income Taxes - Summary of Changes Related to PCAs Gross Unrecognized Tax Benefits Excluding Interest and Penalties (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Balance as of January 1	$ (5.2)	$ (5.8)	$ (4.4)
Increases related to prior years’ tax positions			(2.8)
Increases related to current year tax positions	(0.4)	(0.5)	(0.4)
Decreases related to prior years' tax positions		0.1
Settlements with taxing authorities		0.3	0.7
Expiration of the statute of limitations	0.8	0.7	1.1
Balance at December 31	$ (4.8)	$ (5.2)	$ (5.8)

Goodwill and Intangible Asset61

Goodwill and Intangible Assets -Goodwill - Additional Information (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Goodwill [Line Items]
Goodwill	$ 883.2	$ 737.9	$ 544
Packaging
Goodwill [Line Items]
Goodwill	828	682.7	488.8
Paper
Goodwill [Line Items]
Goodwill	$ 55.2	$ 55.2	$ 55.2

Goodwill and Intangible Asset62

Goodwill and Intangible Assets - Goodwill (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Goodwill [Line Items]
Beginning Balance	$ 737.9	$ 544
Acquisitions	145.3
Ending Balance	883.2	737.9
Columbus Container Inc And TimBar Corporation
Goodwill [Line Items]
Acquisitions		193.9
Packaging
Goodwill [Line Items]
Beginning Balance	682.7	488.8
Acquisitions	145.3
Ending Balance	828	682.7
Packaging | Columbus Container Inc And TimBar Corporation
Goodwill [Line Items]
Acquisitions		193.9
Paper
Goodwill [Line Items]
Beginning Balance	55.2	55.2
Ending Balance	$ 55.2	$ 55.2

Goodwill and Intangible Asset63

Goodwill and Intangible Assets - Goodwill (Parenthetical) (Details) - USD ($) $ in Millions	1 Months Ended			3 Months Ended	12 Months Ended
	Oct. 31, 2017	Nov. 30, 2016	Aug. 31, 2016	Mar. 31, 2017	Dec. 31, 2017
Goodwill [Line Items]
Acquisitions					$ 145.3
Packaging
Goodwill [Line Items]
Acquisitions					145.3
TimBar Corporation
Goodwill [Line Items]
Decrease to goodwill				$ 384.5
TimBar Corporation | Packaging
Goodwill [Line Items]
Acquisitions			$ 157.3
Columbus Container Inc | Packaging
Goodwill [Line Items]
Acquisitions		$ 36.6
Sacramento Container Corporation | Packaging
Goodwill [Line Items]
Acquisitions	$ 151.1
TimBar and Columbus Container | Packaging
Goodwill [Line Items]
Decrease to goodwill					$ 5.8

Goodwill and Intangible Asset64

Goodwill and Intangible Assets - Intangible Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Finite Lived Intangible Assets [Line Items]
Weighted Average Remaining Useful Life (in Years)	11 years 8 months 12 days	12 years 10 months 24 days
Gross Carrying Amount	$ 535	$ 456.4
Accumulated Amortization	$ 125	$ 89.3
Customer Relationships
Finite Lived Intangible Assets [Line Items]
Weighted Average Remaining Useful Life (in Years)	11 years 9 months 18 days	13 years 1 month 6 days
Gross Carrying Amount	$ 497.8	$ 424.5
Accumulated Amortization	$ 109.8	$ 79.8
Trademarks and Trade Names
Finite Lived Intangible Assets [Line Items]
Weighted Average Remaining Useful Life (in Years)	9 years 9 months 18 days	10 years 6 months
Gross Carrying Amount	$ 32.9	$ 27.7
Accumulated Amortization	$ 13.2	$ 8.1
Other Intangible Assets
Finite Lived Intangible Assets [Line Items]
Weighted Average Remaining Useful Life (in Years)	3 years 7 months 6 days	4 years 3 months 18 days
Gross Carrying Amount	$ 4.3	$ 4.2
Accumulated Amortization	$ 2	$ 1.4

Goodwill and Intangible Asset65

Goodwill and Intangible Assets - Intangible Assets (Parenthetical) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Oct. 31, 2017	Oct. 02, 2017	Dec. 31, 2016	Nov. 30, 2016	Aug. 31, 2016
Sacramento Container Corporation
Finite Lived Intangible Assets [Line Items]
Other intangible assets	$ 72.6		$ 72.6
Sacramento Container Corporation | Customer Relationships
Finite Lived Intangible Assets [Line Items]
Other intangible assets		$ 68.4
Sacramento Container Corporation | Trademarks and Trade Names
Finite Lived Intangible Assets [Line Items]
Other intangible assets		4.1
Sacramento Container Corporation | Other Intangible Assets
Finite Lived Intangible Assets [Line Items]
Other intangible assets		$ 0.1
TimBar Corporation
Finite Lived Intangible Assets [Line Items]
Other intangible assets	94.4			$ 94.4
TimBar Corporation | Customer Relationships
Finite Lived Intangible Assets [Line Items]
Other intangible assets						$ 88
TimBar Corporation | Trademarks and Trade Names
Finite Lived Intangible Assets [Line Items]
Other intangible assets						4.9
TimBar Corporation | Other Intangible Assets
Finite Lived Intangible Assets [Line Items]
Other intangible assets						$ 1.5
Columbus Container Inc
Finite Lived Intangible Assets [Line Items]
Other intangible assets	$ 32.3			$ 26.3
Columbus Container Inc | Customer Relationships
Finite Lived Intangible Assets [Line Items]
Other intangible assets					$ 30
Columbus Container Inc | Trademarks and Trade Names
Finite Lived Intangible Assets [Line Items]
Other intangible assets					2.2
Columbus Container Inc | Other Intangible Assets
Finite Lived Intangible Assets [Line Items]
Other intangible assets					$ 0.2

Goodwill and Intangible Asset66

Goodwill and Intangible Assets - Intangible Assets - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Goodwill And Intangible Assets Disclosure [Abstract]
Intangible assets amortization expense	$ 35.7	$ 26.6	$ 22.7
2,018	40.4
2,019	37.8
2,020	37.7
2,021	36.9
2,022	$ 34.5

Accrued Liabilities (Details)

Accrued Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Accrued Liabilities Current [Abstract]
Compensation and benefits	$ 127.5	$ 120.4
Medical insurance and workers’ compensation	23.9	28.8
Customer volume discounts and rebates	23.4	18.9
Franchise, property, sales and use taxes	16	16.7
Environmental liabilities and asset retirement obligations	4	6.4
Severance, retention, and relocation	3.1	3
Other	5.3	7
Total	$ 203.2	$ 201.2

Debt - Summary of Debt (Details

Debt - Summary of Debt (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 13, 2017	Dec. 31, 2016	Sep. 05, 2014	Oct. 22, 2013	Jun. 26, 2012	Mar. 25, 2008
Debt Instrument [Line Items]
Long-term debt	$ 2,645.7		$ 2,658.2
Less current portion	150		25.8
Less unamortized debt issuance costs	15.3		12.5
Long-term debt	$ 2,480.4		$ 2,620
Weighted-average interest rate	3.80%		3.54%
Revolving Credit Facility, due August 2021 | Line of Credit
Debt Instrument [Line Items]
Long-term debt	$ 0		$ 0
Stated interest rate	0.00%		0.00%
Five-Year Term Loan, due August 2021 | Unsecured Debt
Debt Instrument [Line Items]
Long-term debt	$ 0		$ 380.2
Stated interest rate	0.00%		2.02%
Seven-Year Term Loan, due October 2020 | Unsecured Debt
Debt Instrument [Line Items]
Long-term debt	$ 0		$ 630.5
Stated interest rate	0.00%		2.40%
6.50% Senior Notes due March 2018 | Senior Notes
Debt Instrument [Line Items]
Long-term debt	$ 150		$ 150
Stated interest rate	6.50%		6.50%				6.50%
2.45% Senior Notes, due December 2020 | Senior Notes
Debt Instrument [Line Items]
Long-term debt	$ 499.5		$ 0
Stated interest rate	2.45%	2.45%	0.00%
3.90% Senior Notes, due June 2022 | Senior Notes
Debt Instrument [Line Items]
Long-term debt	$ 399.8		$ 399.8
Stated interest rate	3.90%		3.90%			3.90%
4.50% Senior Notes, due November 2023 | Senior Notes
Debt Instrument [Line Items]
Long-term debt	$ 698.8		$ 698.6
Stated interest rate	4.50%		4.50%		4.50%
3.65% Senior Notes, due September 2024 | Senior Notes
Debt Instrument [Line Items]
Long-term debt	$ 399.2		$ 399.1
Stated interest rate	3.65%		3.65%	3.65%
3.40% Senior Notes, due December 2027 | Senior Notes
Debt Instrument [Line Items]
Long-term debt	$ 498.4		$ 0
Stated interest rate	3.40%	3.40%	0.00%
Current Portion of Long-term Debt
Debt Instrument [Line Items]
Weighted-average interest rate	6.50%		2.11%
Long-term Debt, Excluding Current Portion
Debt Instrument [Line Items]
Weighted-average interest rate	3.64%		3.57%

Debt - Summary of Debt (Parenth

Debt - Summary of Debt (Parenthetical) (Details) - USD ($) $ in Millions	Dec. 13, 2017	Sep. 05, 2014	Oct. 22, 2013	Oct. 18, 2013	Jun. 26, 2012	Mar. 25, 2008	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revolving Credit Facility, due August 2021 | Line of Credit
Debt Instrument [Line Items]
Credit facility, expiration date							Aug. 21, 2021	Aug. 21, 2021
Stated interest rate							0.00%	0.00%
Five-Year Term Loan, due August 2021 | Unsecured Debt
Debt Instrument [Line Items]
Credit facility, expiration date				Aug. 21, 2021			Aug. 21, 2021	Aug. 21, 2021
Debt instrument, term				5 years			5 years	5 years
Stated interest rate							0.00%	2.02%
Seven-Year Term Loan, due October 2020 | Unsecured Debt
Debt Instrument [Line Items]
Debt instrument, term							7 years	7 years	7 years
Debt instrument, maturity date				Oct. 18, 2020			Oct. 18, 2020	Oct. 18, 2020	Oct. 18, 2020
Stated interest rate							0.00%	2.40%
6.50% Senior Notes due March 2018 | Senior Notes
Debt Instrument [Line Items]
Debt instrument, maturity date						Mar. 15, 2018	Mar. 15, 2018	Mar. 15, 2018
Stated interest rate						6.50%	6.50%	6.50%
2.45% Senior Notes, due December 2020 | Senior Notes
Debt Instrument [Line Items]
Debt instrument, maturity date	Dec. 15, 2020						Dec. 15, 2020
Stated interest rate	2.45%						2.45%	0.00%
Senior notes, discount							$ 0.5
3.90% Senior Notes, due June 2022 | Senior Notes
Debt Instrument [Line Items]
Debt instrument, maturity date					Jun. 15, 2022		Jun. 15, 2022	Jun. 15, 2022
Stated interest rate					3.90%		3.90%	3.90%
Senior notes, discount							$ 0.2	$ 0.2
4.50% Senior Notes, due November 2023 | Senior Notes
Debt Instrument [Line Items]
Debt instrument, maturity date			Nov. 1, 2023				Nov. 1, 2023	Nov. 1, 2023
Stated interest rate			4.50%				4.50%	4.50%
Senior notes, discount							$ 1.2	$ 1.4
3.65% Senior Notes, due September 2024 | Senior Notes
Debt Instrument [Line Items]
Debt instrument, maturity date		Sep. 15, 2024					Sep. 15, 2024	Sep. 15, 2024
Stated interest rate		3.65%					3.65%	3.65%
Senior notes, discount							$ 0.8	$ 0.9
3.40% Senior Notes, due December 2027 | Senior Notes
Debt Instrument [Line Items]
Debt instrument, maturity date	Dec. 15, 2027						Dec. 15, 2027
Stated interest rate	3.40%						3.40%	0.00%
Senior notes, discount							$ 1.6

Debt - Additional Information (

Debt - Additional Information (Details) - USD ($)	Dec. 13, 2017	Sep. 05, 2014	Oct. 22, 2013	Oct. 18, 2013	Jun. 26, 2012	Mar. 25, 2008	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Net proceeds used to repay outstanding debt	$ 997,800,000						$ 997,800,000	$ 385,000,000
Annual Principal Maturities for Debt [Abstract]
2,018							150,000,000
2,019							0
2,020							500,000,000
2,021							0
2,022							400,000,000
2023 and thereafter							1,600,000,000
Interest payments							96,300,000	88,300,000
Interest payments and redemption premium payments paid for debt obligations									$ 85,500,000
Amortization of net (loss) gain on treasury lock							(5,700,000)	(5,700,000)	(5,700,000)
Amortization of financing costs							4,000,000	$ 1,800,000	1,800,000
Write-off of deferred debt issuance costs							1,800,000
Unsecured Debt
Debt Instrument [Line Items]
Remaining net proceeds used to pay debt issuance costs	6,800,000
Line of Credit
Debt Instrument [Line Items]
Credit facility borrowing capacity				$ 350,000,000
Unused borrowing capacity							326,900,000
Line of Credit | Letter of Credit
Debt Instrument [Line Items]
Outstanding letters of credit							$ 23,100,000
2.45% Senior Notes, due December 2020 | Senior Notes
Debt Instrument [Line Items]
Debt, face amount	$ 500,000,000
Stated interest rate	2.45%						2.45%	0.00%
Debt instrument, maturity date	Dec. 15, 2020						Dec. 15, 2020
3.40% Senior Notes, due December 2027 | Senior Notes
Debt Instrument [Line Items]
Debt, face amount	$ 500,000,000
Stated interest rate	3.40%						3.40%	0.00%
Debt instrument, maturity date	Dec. 15, 2027						Dec. 15, 2027
Seven-Year Term Loan, due October 2020 | Unsecured Debt
Debt Instrument [Line Items]
Debt, face amount				$ 650,000,000
Stated interest rate							0.00%	2.40%
Repayment of debt	$ 625,600,000						$ 630,500,000	$ 6,500,000	$ 6,500,000
Debt instrument, term							7 years	7 years	7 years
Date of term loan repaid				Dec. 13, 2017
Debt instrument, maturity date				Oct. 18, 2020			Oct. 18, 2020	Oct. 18, 2020	Oct. 18, 2020
Seven-Year Term Loan, due October 2020 | Unsecured Debt | London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Applicable margin				1.625%
Five-Year Term Loan, due August 2021 | Unsecured Debt
Debt Instrument [Line Items]
Debt, face amount				$ 385,000,000
Stated interest rate							0.00%	2.02%
Repayment of debt	$ 350,400,000						$ 380,200,000	$ 4,800,000
Debt instrument, term				5 years			5 years	5 years
Credit facility, expiration date				Aug. 21, 2021			Aug. 21, 2021	Aug. 21, 2021
Date of term loan repaid				Dec. 13, 2017
Five-Year Term Loan, due August 2021 | Unsecured Debt | London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Applicable margin				1.25%
Five-Year and Seven-Year Term Loans, due October 2018 and 2020, respectively | Unsecured Debt
Debt Instrument [Line Items]
Debt, face amount				$ 1,650,000,000
6.50% Senior Notes due March 2018 | Senior Notes
Debt Instrument [Line Items]
Debt, face amount						$ 150,000,000
Stated interest rate						6.50%	6.50%	6.50%
Debt instrument, maturity date						Mar. 15, 2018	Mar. 15, 2018	Mar. 15, 2018
3.90% Senior Notes, due June 2022 | Senior Notes
Debt Instrument [Line Items]
Debt, face amount					$ 400,000,000
Stated interest rate					3.90%		3.90%	3.90%
Debt instrument, maturity date					Jun. 15, 2022		Jun. 15, 2022	Jun. 15, 2022
4.50% Senior Notes, due November 2023 | Senior Notes
Debt Instrument [Line Items]
Debt, face amount			$ 700,000,000
Stated interest rate			4.50%				4.50%	4.50%
Debt instrument, maturity date			Nov. 1, 2023				Nov. 1, 2023	Nov. 1, 2023
3.65% Senior Notes, due September 2024 | Senior Notes
Debt Instrument [Line Items]
Debt, face amount		$ 400,000,000
Stated interest rate		3.65%					3.65%	3.65%
Debt instrument, maturity date		Sep. 15, 2024					Sep. 15, 2024	Sep. 15, 2024
Fixed-Rate Senior Notes | Senior Notes
Debt Instrument [Line Items]
Book value of fixed rate debt							$ 2,645,700,000
Long-term debt (fixed-rate debt), fair value							$ 2,734,900,000
Old Five-Year Term Loan | Unsecured Debt
Debt Instrument [Line Items]
Repayment of debt								$ 25,000,000	$ 40,000,000
Debt instrument, term								5 years	5 years

Employee Benefit Plans and Ot71

Employee Benefit Plans and Other Postretirement Benefits - Additional Information (Details) shares in Millions	12 Months Ended
	Dec. 31, 2017USD ($)Ageshares	Dec. 31, 2016USD ($)shares	Dec. 31, 2015USD ($)
Defined Benefit Plan Disclosure [Line Items]
Accumulated other comprehensive loss	$ (156,900,000)	$ (139,600,000)
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) (Pre-Tax)
Accumulated benefit obligation for plans with obligations in excess of plan assets	$ 1,200,000,000
Weighted-Average expected return on plan assets for 2018	6.06%
Fair value of plan assets	$ 954,800,000	$ 830,400,000
Pension Contributions [Abstract]
Expected contribution to qualified plans (at least)	$ 4,600,000
Company's common stock | shares	1.8	2.2
Deferred compensation liability	$ 13,600,000	$ 13,700,000
Minimum
Pension Contributions [Abstract]
Company's contribution to pension plan, percentage	3.00%
Maximum
Pension Contributions [Abstract]
Company's contribution to pension plan, percentage	5.00%
Fixed Income Securities
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) (Pre-Tax)
Percentage of Fair Value	21.00%	54.00%
Other Securities
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) (Pre-Tax)
Percentage of Fair Value	64.00%	1.00%
Boise Inc.
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) (Pre-Tax)
Fair value of plan assets	$ 551,300,000
Boise Inc. | Equities
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) (Pre-Tax)
Target Allocation	44.00%
Boise Inc. | Fixed Income Securities
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) (Pre-Tax)
Target Allocation	54.00%
Boise Inc. | Other Securities
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) (Pre-Tax)
Target Allocation	2.00%
Packaging Corporation of America
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) (Pre-Tax)
Fair value of plan assets	$ 403,500,000
Packaging Corporation of America | Equities
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) (Pre-Tax)
Target Allocation	50.00%
Packaging Corporation of America | Fixed Income Securities
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) (Pre-Tax)
Target Allocation	49.00%
Packaging Corporation of America | Other Securities
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) (Pre-Tax)
Target Allocation	1.00%
Other(Cash) | Boise Inc.
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) (Pre-Tax)
Percentage of Fair Value	100.00%
Postretirement Plans
Defined Benefit Plan Disclosure [Line Items]
Minimum retirement age for medical benefit plan coverage | Age	58
Minimum service period for medical benefit plan coverage, years	10 years
Employee age after which minimum service period to be completed for medical benefit plan coverage | Age	48
Pension Contributions [Abstract]
Contributions to pension plan	$ 1,200,000	$ 1,400,000
Postretirement Health Coverage | Accounting Standards Update 2015-04
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation		(5,100,000)
Accumulated other comprehensive loss		3,100,000
Deferred income taxes		$ 2,000,000
Pension Plans
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) (Pre-Tax)
Weighted-Average expected return on plan assets for 2018	6.55%	6.57%	6.73%
Fair value of plan assets	$ 954,800,000	$ 830,400,000	$ 764,400,000
Pension Contributions [Abstract]
Contributions to pension plan	43,500,000	58,200,000
Pension Plans | Qualified
Pension Contributions [Abstract]
Contributions to pension plan	42,100,000	57,100,000	0
Matching Contributions
Pension Contributions [Abstract]
Company's contribution to defined contribution plans	42,800,000	40,400,000	37,900,000
Service Related Contributions
Pension Contributions [Abstract]
Company's contribution to defined contribution plans	$ 22,400,000	$ 14,900,000	$ 12,400,000

Employee Benefit Plans and Ot72

Employee Benefit Plans and Other Postretirement Benefits - Change in Benefit Obligations and Change in Fair Value of Plan Assets Related to Pension and Postretirement Plans (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Change in Fair Value of Plan Assets [Roll Forward]
Plan assets at fair value at beginning of period		$ 830.4
Fair value of plan assets at plan year end		954.8	$ 830.4
Amounts Recognized on Consolidated Balance Sheets
Noncurrent liabilities		(372.5)	(357.2)
Pension Plans
Change in Benefit Obligations [Roll Forward]
Benefit obligation at beginning of period		1,158.4	1,092.5
Service cost		23.7	24.5	$ 24
Interest cost		41.6	40.9	46.2
Plan amendments		17.3	1.8
Actuarial loss (gain)	[1]	99.3	35.3
Participant contributions			0
Benefits paid		(40.1)	(36.6)
Benefit obligation at plan year end		1,300.2	1,158.4	1,092.5
Accumulated benefit obligation portion of above		1,237.7	1,116.6
Change in Fair Value of Plan Assets [Roll Forward]
Plan assets at fair value at beginning of period		830.4	764.4
Actual return on plan assets		121	44.4
Company contributions		43.5	58.2
Participant contributions			0
Benefits paid		(40.1)	(36.6)
Fair value of plan assets at plan year end		954.8	830.4	764.4
Underfunded status		(345.4)	(328)
Amounts Recognized on Consolidated Balance Sheets
Current liabilities		(1.4)	(1.3)
Noncurrent liabilities		(344)	(326.7)
Accrued obligation recognized at December 31		(345.4)	(328)
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) (Pre-Tax)
Prior service cost (credit)		32.7	21.1
Actuarial loss (gain)		208.5	183.9
Total		241.2	205
Postretirement Plans
Change in Benefit Obligations [Roll Forward]
Benefit obligation at beginning of period		19.5	21.4
Service cost		0.3	0.5	1.7
Interest cost		0.6	0.6	1.2
Plan amendments		(0.5)	(5.3)
Actuarial loss (gain)	[1]	(2.2)	3.7
Participant contributions		1.3	1.3
Benefits paid		(2.5)	(2.7)
Benefit obligation at plan year end		16.5	19.5	$ 21.4
Change in Fair Value of Plan Assets [Roll Forward]
Company contributions		1.2	1.4
Participant contributions		1.3	1.3
Benefits paid		(2.5)	(2.7)
Underfunded status		(16.5)	(19.5)
Amounts Recognized on Consolidated Balance Sheets
Current liabilities		(1)	(1.2)
Noncurrent liabilities		(15.5)	(18.3)
Accrued obligation recognized at December 31		(16.5)	(19.5)
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) (Pre-Tax)
Prior service cost (credit)		(5.3)	(5)
Actuarial loss (gain)		(4)	(1.9)
Total		$ (9.3)	$ (6.9)
[1]	The actuarial loss in 2017 was due primarily to a decrease in the weighted average discount rate used to estimate our pension benefit obligations. In 2016, a decrease in the weighted average discount rate used to estimate our pension benefit obligations and changes in mortality assumptions from the Society of Actuaries resulted in an actuarial loss.

Employee Benefit Plans and Ot73

Employee Benefit Plans and Other Postretirement Benefits - Components of Net Periodic Benefit Cost and Other Comprehensive (Income) Loss (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost		$ 23.7	$ 24.5	$ 24
Interest cost		41.6	40.9	46.2
Expected return on plan assets		(53.9)	(49.5)	(53.1)
Net amortization of unrecognized amounts, Prior service cost (credit)		5.8	5.7	5.5
Net amortization of unrecognized amounts, Actuarial loss (gain)		7.6	5.8	8.7
Net periodic benefit cost		24.8	27.4	31.3
Changes in plan assets and benefit obligations recognized in other comprehensive (income) loss
Actuarial net loss (gain)		32.2	40.4	(14.5)
Prior service cost (credit)		17.4	1.8	3
Amortization of prior service cost (credit)		(5.8)	(5.7)	(5.5)
Amortization of actuarial loss (gain)		(7.6)	(5.8)	(8.7)
Total recognized in other comprehensive loss (income)	[1]	36.2	30.7	(25.7)
Total recognized in net periodic benefit cost and other comprehensive loss (income) (pre-tax)		61	58.1	5.6
Postretirement Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost		0.3	0.5	1.7
Interest cost		0.6	0.6	1.2
Net amortization of unrecognized amounts, Prior service cost (credit)		(0.2)	(0.1)	0.1
Net amortization of unrecognized amounts, Actuarial loss (gain)		(0.1)	(0.4)	0.1
Net periodic benefit cost		0.6	0.6	3.1
Changes in plan assets and benefit obligations recognized in other comprehensive (income) loss
Actuarial net loss (gain)		(2.2)	3.6	(11.4)
Prior service cost (credit)		(0.6)	(5.3)
Amortization of prior service cost (credit)		0.2	(0.3)	(0.1)
Amortization of actuarial loss (gain)		0.1	0.8	(0.1)
Total recognized in other comprehensive loss (income)	[1]	(2.5)	(1.2)	(11.6)
Total recognized in net periodic benefit cost and other comprehensive loss (income) (pre-tax)		$ (1.9)	$ (0.6)	$ (8.5)
[1]	Accumulated losses in excess of 10% of the greater of the projected benefit obligation or the market-related value of assets will be recognized on a straight-line basis over the average remaining service period of active employees in PCA plans (which is between seven to ten years) and over the average remaining lifetime of inactive participants of Boise plans (which is between 25 and 28 years), to the extent that losses are not offset by gains in subsequent years. The estimated net loss and prior service cost that will be amortized from “Accumulated other comprehensive loss” into net periodic benefit in 2018 is $15.8 million.

Employee Benefit Plans and Ot74

Employee Benefit Plans and Other Postretirement Benefits - Components of Net Periodic Benefit Cost and Other Comprehensive (Income) Loss (Parenthetical) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017USD ($)
Defined Benefit Plan Disclosure [Line Items]
Accumulated losses, excess percentage threshold required on projected benefit obligation	10.00%
Estimated net periodic benefit cost for 2018	$ 15.8
Packaging Corporation of America | Minimum
Defined Benefit Plan Disclosure [Line Items]
Average remaining service period of active employees used for recognition of market-related value of assets	7 years
Packaging Corporation of America | Maximum
Defined Benefit Plan Disclosure [Line Items]
Average remaining service period of active employees used for recognition of market-related value of assets	10 years
Boise Inc. | Minimum
Defined Benefit Plan Disclosure [Line Items]
Average remaining lifetime of inactive participants used for recognition of market-related value of assets	25 years
Boise Inc. | Maximum
Defined Benefit Plan Disclosure [Line Items]
Average remaining lifetime of inactive participants used for recognition of market-related value of assets	28 years

Employee Benefit Plans and Ot75

Employee Benefit Plans and Other Postretirement Benefits - Schedule of Weighted-Average Assumptions Used to Determine Benefit Obligations and Net Periodic Benefit Cost (Details)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Weighted-Average Assumptions Used to Determine Net Periodic Benefit Cost, Expected return on plan assets	6.06%
Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Weighted-Average Assumptions Used to Determine Benefit Obligation, Discount Rate	3.66%	4.24%	4.51%
Weighted-Average Assumptions Used to Determine Benefit Obligations, Rate of compensation increase	4.00%	4.00%	4.00%
Weighted-Average Assumptions Used to Determine Net Periodic Benefit Cost, Discount rate	4.24%	4.49%	4.14%
Weighted-Average Assumptions Used to Determine Net Periodic Benefit Cost, Expected return on plan assets	6.55%	6.57%	6.73%
Weighted-Average Assumptions Used to Determine Net Periodic Benefit Cost, Rate of compensation increase	4.00%	4.00%	4.00%
Postretirement Plans
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Weighted-Average Assumptions Used to Determine Benefit Obligation, Discount Rate	3.55%	3.91%	4.35%
Weighted-Average Assumptions Used to Determine Net Periodic Benefit Cost, Discount rate	3.92%	4.17%	3.95%

Employee Benefit Plans and Ot76

Employee Benefit Plans and Other Postretirement Benefits - Schedule of Assumed Health Care Cost Trend Rates for Postretirement Benefits (Details) - Postretirement Plans	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Health care cost trend rate assumed for next year	7.57%	7.35%	7.60%
Rate to which the cost trend rate is assumed to decline (the ultimate trend rate)	4.44%	4.50%	4.50%
Year that the rate reaches the ultimate trend rate	2,027	2,025	2,024

Employee Benefit Plans and Ot77

Employee Benefit Plans and Other Postretirement Benefits - Schedule of Effects of One-Percentage Point Change in Assumed Health Care Cost Trends on Postretirement Benefits (Details) - Postretirement Plans $ in Millions	12 Months Ended
	Dec. 31, 2017USD ($)
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Effect on postretirement benefit obligation, 1-Percentage Point Decrease	$ (0.6)
Effect on postretirement benefit obligation, 1-Percentage Point Increase	0.6
Effect on net postretirement benefit cost, 1-Percentage Point Increase	$ 0.1

Employee Benefit Plans and Ot78

Employee Benefit Plans and Other Postretirement Benefits - Schedule of Pension Plan Asset Investments and Target Allocations (Details)	Jan. 05, 2018	Dec. 31, 2017	Dec. 31, 2016
Fixed Income Securities
Defined Benefit Plan Disclosure [Line Items]
Percentage of Fair Value		21.00%	54.00%
Fixed Income Securities | Subsequent Event
Defined Benefit Plan Disclosure [Line Items]
Percentage of Fair Value	52.00%
International Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Percentage of Fair Value		6.00%	23.00%
International Equity Securities | Subsequent Event
Defined Benefit Plan Disclosure [Line Items]
Percentage of Fair Value	28.00%
U.S. Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Percentage of Fair Value		9.00%	21.00%
U.S. Equity Securities | Subsequent Event
Defined Benefit Plan Disclosure [Line Items]
Percentage of Fair Value	20.00%
Real Estate Securities
Defined Benefit Plan Disclosure [Line Items]
Percentage of Fair Value			1.00%
Other Securities
Defined Benefit Plan Disclosure [Line Items]
Percentage of Fair Value		64.00%	1.00%

Employee Benefit Plans and Ot79

Employee Benefit Plans and Other Postretirement Benefits - Fair Value Measurements of Plan Assets (Details) - USD ($) $ in Millions		Dec. 31, 2017		Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets		$ 954.8		$ 830.4
Significant unobservable input (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets		4.2		5.7
Cash and Short-term Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets		608.1	[1]	1.5
Cash and Short-term Investments | Quoted prices in active markets for identical assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets		602.4	[1]	0
Cash and Short-term Investments | Significant other observable inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets		5.7	[1]	1.5
Cash and Short-term Investments | Significant unobservable input (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets		0	[1]	0
Domestic equities (Common/Collective Trust Funds)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets	[2]	84.1		107.9
Domestic equities (Common/Collective Trust Funds) | Quoted prices in active markets for identical assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets	[2]	0		0
Domestic equities (Common/Collective Trust Funds) | Significant other observable inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets	[2]	84.1		107.9
Domestic equities (Common/Collective Trust Funds) | Significant unobservable input (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets	[2]	0		0
Fixed Income (Mutual Funds)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets		95.4		173.2
Fixed Income (Mutual Funds) | Quoted prices in active markets for identical assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets		95.4		108.4
Fixed Income (Mutual Funds) | Significant other observable inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets		0		64.8
Fixed Income (Mutual Funds) | Significant unobservable input (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets		0		0
International equities (Common/Collective Trust Funds)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets	[2]	5.6		124.5
International equities (Common/Collective Trust Funds) | Quoted prices in active markets for identical assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets	[2]	0		0
International equities (Common/Collective Trust Funds) | Significant other observable inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets	[2]	5.6		124.5
International equities (Common/Collective Trust Funds) | Significant unobservable input (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets	[2]	0		0
Fixed Income (Common/Collective Trust Funds)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets	[2]	59.8		271.6
Fixed Income (Common/Collective Trust Funds) | Quoted prices in active markets for identical assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets	[2]	0		0
Fixed Income (Common/Collective Trust Funds) | Significant other observable inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets	[2]	59.8		271.6
Fixed Income (Common/Collective Trust Funds) | Significant unobservable input (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets	[2]	0		0
International equities (Mutual Funds)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets		56.1		68.7
International equities (Mutual Funds) | Quoted prices in active markets for identical assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets		56.1		68.7
International equities (Mutual Funds) | Significant other observable inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets		0		0
International equities (Mutual Funds) | Significant unobservable input (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets		0		0
Fixed Income (Corporate and Government Bonds)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets		41.3
Fixed Income (Corporate and Government Bonds) | Quoted prices in active markets for identical assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets		41.3
Fixed Income (Corporate and Government Bonds) | Significant other observable inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets		0
Fixed Income (Corporate and Government Bonds) | Significant unobservable input (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets		0
Private Equity Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets	[3]	4.2		5.7
Private Equity Securities | Quoted prices in active markets for identical assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets	[3]	0		0
Private Equity Securities | Significant other observable inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets	[3]	0		0
Private Equity Securities | Significant unobservable input (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets	[3]	4.2		5.7
Total Securities at Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets		954.6		828.4
Total Securities at Fair Value | Quoted prices in active markets for identical assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets		795.2		252.4
Total Securities at Fair Value | Significant other observable inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets		155.2		570.3
Total Securities at Fair Value | Significant unobservable input (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets		4.2		5.7
Receivables and Accruals, Net [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets		$ 0.2		2
Domestic equities (Mutual Funds)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets				65.7
Domestic equities (Mutual Funds) | Quoted prices in active markets for identical assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets				65.7
Domestic equities (Mutual Funds) | Significant other observable inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets				0
Domestic equities (Mutual Funds) | Significant unobservable input (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets				0
Real Estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets				9.6
Real Estate | Quoted prices in active markets for identical assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets				9.6
Real Estate | Significant other observable inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets				0
Real Estate | Significant unobservable input (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets				$ 0
[1]	Short-term investments and the Boise pension plan assets classified as cash as of December 31, 2017. The Boise pension plan assets were subsequently allocated to equities and fixed income securities on January 5, 2018 after consolidating with the PCA pension plan assets under one trustee.
[2]	Investments in common/collective trust funds valued using net asset values (NAV) provided by the administrator of the funds. The NAV is based on the value of the underlying assets owned by the fund, minus its liabilities, and then divided by the number of units outstanding. While the underlying assets are actively traded on an exchange, the funds are not. There are currently no redemption restrictions on these investments. There are certain funds with one-day redeemable notice.
[3]	Investments in this category are invested in the Pantheon Global Secondary Fund IV, LP. The fund specializes in investments in the private equity secondary market and occasionally directly in private companies to maximize capital growth. Fund investments are carried at fair value as determined quarterly using the market approach to estimate the fair value of private investments. The market approach utilizes prices and other relevant information generated by market transactions, type of security, size of the position, degree of liquidity, restrictions on the disposition, latest round of financing data, current financial position, and operating results, among other factors. In circumstances where fair values are not provided with respect to any of the company's fund investments, the investment advisor will seek to determine the fair value of such investments based on information provided by the general partners or managers of such funds or from other sources. Audited financial statements are provided by fund management annually. Notwithstanding the above, the variety of valuation bases adopted and quality of management data of the ultimate underlying investee companies means that there are inherent difficulties in determining the value of the investments. Amounts realized on the sale of these investments may differ from the calculated values. Boise had originally committed to a $15.0 million investment, with $5.0 million of the commitment unfunded at December 31, 2017.

Employee Benefit Plans and Ot80

Employee Benefit Plans and Other Postretirement Benefits - Fair Value Measurements of Plan Assets (Parenthetical) (Details) - Private Equity Securities - Significant unobservable input (Level 3) $ in Millions	Dec. 31, 2017USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment commitment	$ 15
Unfunded portion of investment commitment	$ 5

Employee Benefit Plans and Ot81

Employee Benefit Plans and Other Postretirement Benefits - Summary of Changes in Pension Plans' Level 3 Assets (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017USD ($)
Level 3 fair value of pension plans' assets [Roll Forward]
Plan assets at fair value at beginning of period	$ 830.4
Fair value of plan assets at plan year end	954.8
Significant unobservable input (Level 3)
Level 3 fair value of pension plans' assets [Roll Forward]
Plan assets at fair value at beginning of period	5.7
Sales	(1.5)
Fair value of plan assets at plan year end	$ 4.2

Employee Benefit Plans and Ot82

Employee Benefit Plans and Other Postretirement Benefits - Schedule of Estimated Benefit Payments (Details) $ in Millions	Dec. 31, 2017USD ($)
Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
2,018	$ 45.4
2,019	49.3
2,020	53.2
2,021	57
2022 - 2025	407.9
Postretirement Plans
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
2,018	1
2,019	1
2,020	1
2,021	0.9
2022 - 2025	$ 5.4

Asset Retirement Obligations -

Asset Retirement Obligations - Changes to Asset Retirement Obligation (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Asset retirement obligation at beginning of period	$ 28	$ 26.2
Accretion expense	1.3	2.3
Payments	(2.3)	(2.2)
Revisions in estimated cash flows	7.9	1.2
Liabilities incurred	0.2	0.5
Asset retirement obligation at end of period	$ 35.1	$ 28

Share-Based Compensation - Addi

Share-Based Compensation - Additional Information (Details)	12 Months Ended
	Dec. 31, 2017shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Long-term equity incentive plan, termination date	May 1, 2023
Number of shares authorized under plan	10,600,000
Number of shares available for future issuance under share-based plan	1,000,000
Restricted Stock | Officers and Employees
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	4 years
Performance Units | Key Employees
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	4 years

Share-Based Compensation - Summ

Share-Based Compensation - Summary of Restricted Stock and Performance Units Activity (Details) - $ / shares		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Restricted Stock
Restricted Stock and Performance Units [Roll Forward]
Outstanding at January 1		786,079	1,007,794	1,184,299
Granted		173,199	242,835	218,957
Vested	[1]	(213,992)	(443,627)	(389,481)
Forfeitures		(5,554)	(20,923)	(5,981)
Outstanding at December 31		739,732	786,079	1,007,794
Restricted Stock and Performance Units (Weighted Average Grant-date Fair Value) [Abstract]
Weighted Average Grant-Date Fair Value, Outstanding at January 1		$ 63.44	$ 49.47	$ 41.71
Weighted Average Grant-Date Fair Value, Granted		107.57	67.48	65.16
Weighted Average Grant-Date Fair Value, Vested	[1]	51.37	34.11	32.77
Weighted Average Grant-Date Fair Value, Forfeitures		69.03	59.63	66.42
Weighted Average Grant-Date Fair Value, Outstanding at December 31		$ 77.23	$ 63.44	$ 49.47
Performance Units
Restricted Stock and Performance Units [Roll Forward]
Outstanding at January 1		232,088	175,675	127,489
Granted		61,861	77,017	53,102
Vested	[2]	(67,391)	(20,604)	(4,916)
Outstanding at December 31		226,558	232,088	175,675
Restricted Stock and Performance Units (Weighted Average Grant-date Fair Value) [Abstract]
Weighted Average Grant-Date Fair Value, Outstanding at January 1		$ 62.68	$ 59.94	$ 58.25
Weighted Average Grant-Date Fair Value, Granted		108.19	67.57	65.04
Weighted Average Grant-Date Fair Value, Vested	[2]	56.08	57.58	71.19
Weighted Average Grant-Date Fair Value, Outstanding at December 31		$ 77.07	$ 62.68	$ 59.94
[1]	The total fair value of awards upon vesting for the years ended December 31, 2017, 2016, and 2015 was $23.3 million, $28.8 million, and $26.3 million, respectively.
[2]	The total fair value of awards upon vesting for the years ended December 31, 2017, 2016, and 2015 was $7.5 million, $1.1 million, and $0.3 million, respectively. Upon vesting of the awards in 2016 and 2015, PCA issued 21,111 and 5,090 shares, which included 507 and 174 shares, respectively, for dividends accrued during the vesting period.

Share-Based Compensation - Su86

Share-Based Compensation - Summary of Restricted Stock and Performance Units Activity (Parenthetical) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of awards vested	$ 23.3	$ 28.8	$ 26.3
Performance Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of awards vested	$ 7.5	$ 1.1	$ 0.3
Stock Issued During Period, Shares, Restricted Stock Award, Gross		21,111	5,090
Common Stock Dividends, Shares		507	174

Share-Based Compensation - Comp

Share-Based Compensation - Compensation Expense for Restricted Stock and Performance Units (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Impact on income before income taxes	$ 20.6	$ 19.7	$ 18.2
Income tax benefit	(7.9)	(7.7)	(7.1)
Impact on net income	12.7	12	11.1
Restricted Stock
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Impact on income before income taxes	15	15.8	15.2
Performance Units
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Impact on income before income taxes	$ 5.6	$ 3.9	$ 3

Share-Based Compensation - Unre

Share-Based Compensation - Unrecognized Compensation Expense for Share-Based Awards (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense	$ 40.4
Remaining weighted-average recognition period	2 years 7 months 6 days
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense	$ 30.6
Remaining weighted-average recognition period	2 years 6 months
Performance Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense	$ 9.8
Remaining weighted-average recognition period	2 years 9 months 18 days

Derivative Instruments and He89

Derivative Instruments and Hedging Activities - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2008
Derivative [Line Items]
Net amount of settlement gains (losses) on derivative instruments included in accumulated OCI to be amortized over next 12 months, before tax	$ (5.3)
Net amount of settlement gains (losses) on derivative instruments included in accumulated OCI to be amortized over next 12 months, after tax	$ (3.3)
2008 Interest Rate Protection Agreement
Derivative [Line Items]
Payments for (Proceeds from) settlement of interest rate protection agreement				$ 4.4
2010 Interest Rate Protection Agreement
Derivative [Line Items]
Payments for (Proceeds from) settlement of interest rate protection agreement			$ (9.9)
2011 Interest Rate Protection Agreement
Derivative [Line Items]
Payments for (Proceeds from) settlement of interest rate protection agreement		$ 65.5

Derivative Instruments and He90

Derivative Instruments and Hedging Activities - Impact of Derivative Instruments on Consolidated Statements of Income and OCI (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Interest Expense
Derivative Instruments, Gain (Loss) [Line Items]
Loss Reclassified from Accumulated OCI into Income (Effective Portion)	$ (5.7)	$ (5.7)	$ (5.7)
Treasury Locks, Net Of Tax
Derivative Instruments, Gain (Loss) [Line Items]
Net Loss Recognized in Accumulated OCI (Effective Portion)	$ (14.2)	$ (17.7)

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Details) - USD ($) $ / shares in Units, shares in Millions	Jan. 12, 2018	Dec. 14, 2017	Apr. 15, 2015	Feb. 26, 2015	Dec. 09, 2014	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Feb. 25, 2016
Common stock dividends paid	$ 59,400,000					$ 237,600,000	$ 216,100,000	$ 200,800,000
Dividends paid per common share (in dollars per share)		$ 0.63	$ 0.63
Dividends declared per common share						$ 2.52	$ 2.36	$ 2.20
Stock repurchase program, authorized amount									$ 200,000,000
Repurchases of common stock under stock repurchase program						0
Common stock repurchase authorization amount available						$ 193,000,000
Annual Dividend [Member]
Dividends declared per common share				$ 2.52	$ 2.20

Stockholders' Equity - Share Re

Stockholders' Equity - Share Repurchase Program (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Equity [Abstract]
Common stock repurchased and retired, shares	1,987,187	2,326,493
Common stock repurchased and retired, weighted average price per share	$ 50.49	$ 66.50
Common stock repurchased and retired, total value	$ 100.3	$ 154.7

Stockholders' Equity - Changes

Stockholders' Equity - Changes in Accumulated Other Comprehensive Income by Component (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at December 31, 2016	$ (139.6)
Other comprehensive income before reclassifications	(28.8)
Amounts reclassified from AOCI	11.5
Other comprehensive income (loss)	(17.3)	$ (14.7)	$ 29
Balance at December 31, 2017	(156.9)	(139.6)
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at December 31, 2016	(0.1)
Other comprehensive income before reclassifications	0
Amounts reclassified from AOCI	(0.2)
Other comprehensive income (loss)	(0.2)
Balance at December 31, 2017	(0.3)	(0.1)
Unfunded Employee Benefit Obligations
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at December 31, 2016	(121.5)
Other comprehensive income before reclassifications	(28.8)
Amounts reclassified from AOCI	8.2
Other comprehensive income (loss)	(20.6)
Balance at December 31, 2017	(142.1)	(121.5)
Treasury Lock | Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at December 31, 2016	(17.7)
Other comprehensive income before reclassifications	0
Amounts reclassified from AOCI	3.5
Other comprehensive income (loss)	3.5
Balance at December 31, 2017	(14.2)	(17.7)
Foreign Exchange Contract | Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at December 31, 2016	(0.3)
Other comprehensive income before reclassifications	0
Amounts reclassified from AOCI	0
Other comprehensive income (loss)	0
Balance at December 31, 2017	$ (0.3)	$ (0.3)

Stockholders' Equity - Reclassi

Stockholders' Equity - Reclassifications Out of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions

3 Months Ended

12 Months Ended

Dec. 31, 2017

[2]

Sep. 30, 2017

[3]

Jun. 30, 2017

[4]

Mar. 31, 2017

[5]

Dec. 31, 2016

[6]

Sep. 30, 2016

[7]

Jun. 30, 2016

[8]

Mar. 31, 2016

[9]

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]

Interest expense, net

$ (102.6)

[1]

$ (91.8)

$ (85.5)

Income before taxes

828.6

688.5

664.5

Income tax benefit

(160)

(238.9)

(227.7)

Net income

$ 268.9

$ 139.1

$ 143.2

$ 117.4

$ 110.6

$ 119.4

$ 115.9

$ 103.7

668.6

449.6

$ 436.8

Unfunded Employee Benefit Obligations | Reclassification out of Accumulated Other Comprehensive Income [Member]

Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]

Amortization of prior service costs

(5.6)

(5.5)

Amortization of actuarial gains / (losses)

(7.5)

(5.4)

Income before taxes

(13.1)

(10.9)

Income tax benefit

4.9

4.2

Net income

(8.2)

(6.7)

Treasury Lock | Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges | Reclassification out of Accumulated Other Comprehensive Income [Member]

Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]

Interest expense, net

(5.7)

(5.7)

Income tax benefit

2.2

2.2

Net income

$ (3.5)

$ (3.5)

[1]

Includes $1.8 million of expense related to the write-off of deferred debt issuance costs in connection with the December 2017 debt refinancing.

[2]

Includes $7.6 million of income primarily related to the sale of land corresponding to the closure of a corrugated products facility, partially offset by closure costs related to corrugated products facilities, a paper administration facility, and a corporate administration facility ($4.7 million after-tax or $0.05 per diluted share) and $0.9 million of charges related to the Sacramento Container acquisition and integration costs related to other recent acquisitions ($0.5 million after-tax or $0.01 per diluted share), and $8.0 million of charges related to our determination to discontinue production of uncoated free sheet and coated one-side grades at the Wallula, Washington mill in the second quarter of 2018 and convert the No. 3 paper machine to a high-performance 100% virgin kraft linerboard machine ($4.6 million after-tax or $0.05 per diluted share). Also includes $1.8 million of expense related to the write-off of deferred debt issuance costs in connection with the December 2017 debt refinancing ($1.1 million after-tax or $0.01 per diluted share), $2.0 million gain related to the expiration of a repurchase option corresponding to timberland previously sold ($1.2 million after-tax or 0.01 per diluted share), and $122.1 million of estimated income tax benefit related to the enactment in December 2017 of the Tax Cuts and Jobs Act (H.R.1) primarily for the re-measurement of our net deferred tax liability as a result of the reduction in the U.S. corporate income tax rate ($1.29 per diluted share).

[3]

Includes $0.9 million of charges related to the closure of corrugated products facilities, a paper administration facility, and a lump sum settlement of a multiemployer pension plan withdrawal liability for one of our corrugated products facilities ($0.6 million after-tax or $0.01 per diluted share) and $0.5 million of charges related to the Sacramento Container acquisition and integration costs related to other recent acquisitions ($0.3 million after-tax or $0.0 per diluted share). Also includes $25.3 million of charges related to our determination to discontinue production of uncoated free sheet and coated one-side grades at the Wallula, Washington mill in the second quarter of 2018 and convert the No. 3 paper machine to a high-performance 100% virgin kraft linerboard machine ($15.5 million after-tax or $0.16 per diluted share) and $3.3 million of tax expense for the change in value of deferred taxes as a result of an internal legal entity consolidation that will simplify future operating activities ($0.04 per diluted share).

[4]

Includes $0.3 million of charges related to the closure of corrugated products facilities ($0.3 million after-tax or $0.0 per diluted share) and $0.2 million of charges related to TimBar Corporation and Columbus Container integration costs ($0.1 after-tax or $0.0 per diluted share).

[5]

Includes $0.6 million of charges related to the closure of corrugated products facilities and lump sum settlement of a multiemployer pension plan withdrawal liability for one of corrugated products facilities ($0.4 million after-tax or $0.1 per diluted share) and $0.2 million of charges related to TimBar Corporation and Columbus Container integration costs ($0.1 million after-tax or $0.0 per diluted share). Also includes $5.0 million of costs for the property damage and business interruption insurance deductible corresponding to the February 2017 explosion at our DeRidder, Louisiana mill ($3.1 million after-tax or $0.03 per diluted share) and $2.3 million of income related to a working capital adjustment from the April 2015 sale of our Hexacomb corrugated manufacturing operations in Europe and Mexico ($1.4 million after-tax or $0.01 per diluted share).

[6]

Includes $4.5 million of charges related to the closure of a corrugated products facility and a paper products facility ($2.9 million after-tax or $0.03 per diluted share), $2.7 million of costs related to ceased production of softwood market pulp operations at our Wallula, Washington mill and the permanent shutdown of the No. 1 machine ($1.8 million after-tax or $0.02 per diluted share), and $1.2 million of charges related to the TimBar Corporation and Columbus Container acquisitions and integration ($0.8 million after-tax or $0.01 per diluted share).

[7]

Includes $2.0 million of charges related to the closure of a corrugated products facility and a paper products facility ($1.4 million after-tax or $0.02 per diluted share) and $2.9 million of charges related to the TimBar Corporation and Columbus Container acquisitions and integration ($1.9 million after-tax or $0.02 per diluted share).

[8]

Includes $2.6 million of charges related to the closure of corrugated products facilities, a paper products facility, and a lump sum settlement of a multiemployer pension plan withdrawal liability for one of our corrugated products facilities ($1.6 million after-tax or $0.02 per diluted share) and $0.3 million of charges related to the TimBar Corporation acquisition and integration ($0.2 million after-tax or $0.0 per diluted share).

[9]

Includes $2.8 million of charges related to the closure of a corrugated products facility and a paper products facility ($1.9 million after-tax or $0.02 per diluted share).

Stockholders' Equity - Change95

Stockholders' Equity - Changes in Accumulated Other Comprehensive Income by Component (Parenthetical) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017USD ($)
Equity [Abstract]
Net amount of settlement gains (losses) on derivative instruments included in accumulated OCI to be amortized over next 12 months, before tax	$ (5.3)
Net amount of settlement gains (losses) on derivative instruments included in accumulated OCI to be amortized over next 12 months, after tax	$ (3.3)

Concentrations of Risk - Additi

Concentrations of Risk - Additional Information (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017USD ($)employee	Dec. 31, 2016USD ($)
Concentration Risk [Line Items]
Accounts receivable, net, current	$ 830.7	$ 689.2
Number of employees of PCA | employee	14,600
Percentage of hourly employees represented by unions	65.00%
Workforce Subject to Collective Bargaining Arrangements | Customer Concentration Risk
Concentration Risk [Line Items]
Concentration risk, percentage	45.00%
Workforce Subject to Collective Bargaining Arrangements Expiring within One Year | Customer Concentration Risk
Concentration Risk [Line Items]
Concentration risk, percentage	20.00%
Office Depot | Credit Concentration Risk
Concentration Risk [Line Items]
Accounts receivable, net, current	$ 33.3	$ 31.8
Office Depot | Total Company Sales Revenue | Customer Concentration Risk
Concentration Risk [Line Items]
Concentration risk, percentage	7.00%	8.00%
Office Depot | Total Company Receivables | Customer Concentration Risk
Concentration Risk [Line Items]
Concentration risk, percentage	4.00%	5.00%
Paper | Office Depot | Paper Segment Sales Revenue | Customer Concentration Risk
Concentration Risk [Line Items]
Concentration risk, percentage	43.00%	42.00%

Transactions With Related Par97

Transactions With Related Parties - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Related Party Transaction [Line Items]
Carrying amount of LTP's assets	$ 3	$ 5
Carrying amount of LTP's liabilities	$ 3	5
Boise Cascade Co-Owner of LTP
Related Party Transaction [Line Items]
Variable interest entity, ownership percentage	50.00%
Boise Cascade Co-Owner of LTP | Fiber
Related Party Transaction [Line Items]
Revenue from related parties	$ 86.4	86.9	$ 88.8
Fiber costs from related parties	86.4	86.9	88.8
Boise Cascade Co-Owner of LTP | Wood Products, Including Chips and Logs
Related Party Transaction [Line Items]
Fiber costs from related parties	$ 16.6	$ 17.2	$ 20.7
Packaging Corporation of America
Related Party Transaction [Line Items]
Variable interest entity, ownership percentage	50.00%

Segment Information - Additiona

Segment Information - Additional Information (Details)

3 Months Ended

12 Months Ended

Dec. 31, 2017USD ($)

Sep. 30, 2017USD ($)

[2]

Jun. 30, 2017USD ($)

[3]

Mar. 31, 2017USD ($)

[4]

Dec. 31, 2016USD ($)

Sep. 30, 2016USD ($)

[6]

Jun. 30, 2016USD ($)

[7]

Mar. 31, 2016USD ($)

[8]

Dec. 31, 2017USD ($)Segment

Dec. 31, 2016USD ($)

Dec. 31, 2015USD ($)

Segment Reporting Information [Line Items]

Number of reportable segments | Segment

3

Net sales

$ 1,684,300,000

[1]

$ 1,640,100,000

$ 1,584,000,000

$ 1,536,500,000

$ 1,476,600,000

[5]

$ 1,484,000,000

$ 1,417,400,000

$ 1,401,000,000

$ 6,444,900,000

$ 5,779,000,000

$ 5,741,700,000

Foreign operations

Segment Reporting Information [Line Items]

Net sales

390,300,000

289,500,000

177,200,000

Long-Lived Assets

$ 0

$ 0

$ 0

$ 0

Office Depot | Total Company Sales Revenue | Customer Concentration Risk

Segment Reporting Information [Line Items]

Concentration risk, percentage

7.00%

8.00%

Paper

Segment Reporting Information [Line Items]

Net sales

$ 1,051,800,000

$ 1,093,900,000

$ 1,143,100,000

[1]

Includes $7.6 million of income primarily related to the sale of land corresponding to the closure of a corrugated products facility, partially offset by closure costs related to corrugated products facilities, a paper administration facility, and a corporate administration facility ($4.7 million after-tax or $0.05 per diluted share) and $0.9 million of charges related to the Sacramento Container acquisition and integration costs related to other recent acquisitions ($0.5 million after-tax or $0.01 per diluted share), and $8.0 million of charges related to our determination to discontinue production of uncoated free sheet and coated one-side grades at the Wallula, Washington mill in the second quarter of 2018 and convert the No. 3 paper machine to a high-performance 100% virgin kraft linerboard machine ($4.6 million after-tax or $0.05 per diluted share). Also includes $1.8 million of expense related to the write-off of deferred debt issuance costs in connection with the December 2017 debt refinancing ($1.1 million after-tax or $0.01 per diluted share), $2.0 million gain related to the expiration of a repurchase option corresponding to timberland previously sold ($1.2 million after-tax or 0.01 per diluted share), and $122.1 million of estimated income tax benefit related to the enactment in December 2017 of the Tax Cuts and Jobs Act (H.R.1) primarily for the re-measurement of our net deferred tax liability as a result of the reduction in the U.S. corporate income tax rate ($1.29 per diluted share).

[2]

Includes $0.9 million of charges related to the closure of corrugated products facilities, a paper administration facility, and a lump sum settlement of a multiemployer pension plan withdrawal liability for one of our corrugated products facilities ($0.6 million after-tax or $0.01 per diluted share) and $0.5 million of charges related to the Sacramento Container acquisition and integration costs related to other recent acquisitions ($0.3 million after-tax or $0.0 per diluted share). Also includes $25.3 million of charges related to our determination to discontinue production of uncoated free sheet and coated one-side grades at the Wallula, Washington mill in the second quarter of 2018 and convert the No. 3 paper machine to a high-performance 100% virgin kraft linerboard machine ($15.5 million after-tax or $0.16 per diluted share) and $3.3 million of tax expense for the change in value of deferred taxes as a result of an internal legal entity consolidation that will simplify future operating activities ($0.04 per diluted share).

[3]

Includes $0.3 million of charges related to the closure of corrugated products facilities ($0.3 million after-tax or $0.0 per diluted share) and $0.2 million of charges related to TimBar Corporation and Columbus Container integration costs ($0.1 after-tax or $0.0 per diluted share).

[4]

Includes $0.6 million of charges related to the closure of corrugated products facilities and lump sum settlement of a multiemployer pension plan withdrawal liability for one of corrugated products facilities ($0.4 million after-tax or $0.1 per diluted share) and $0.2 million of charges related to TimBar Corporation and Columbus Container integration costs ($0.1 million after-tax or $0.0 per diluted share). Also includes $5.0 million of costs for the property damage and business interruption insurance deductible corresponding to the February 2017 explosion at our DeRidder, Louisiana mill ($3.1 million after-tax or $0.03 per diluted share) and $2.3 million of income related to a working capital adjustment from the April 2015 sale of our Hexacomb corrugated manufacturing operations in Europe and Mexico ($1.4 million after-tax or $0.01 per diluted share).

[5]

Includes $4.5 million of charges related to the closure of a corrugated products facility and a paper products facility ($2.9 million after-tax or $0.03 per diluted share), $2.7 million of costs related to ceased production of softwood market pulp operations at our Wallula, Washington mill and the permanent shutdown of the No. 1 machine ($1.8 million after-tax or $0.02 per diluted share), and $1.2 million of charges related to the TimBar Corporation and Columbus Container acquisitions and integration ($0.8 million after-tax or $0.01 per diluted share).

[6]

Includes $2.0 million of charges related to the closure of a corrugated products facility and a paper products facility ($1.4 million after-tax or $0.02 per diluted share) and $2.9 million of charges related to the TimBar Corporation and Columbus Container acquisitions and integration ($1.9 million after-tax or $0.02 per diluted share).

[7]

Includes $2.6 million of charges related to the closure of corrugated products facilities, a paper products facility, and a lump sum settlement of a multiemployer pension plan withdrawal liability for one of our corrugated products facilities ($1.6 million after-tax or $0.02 per diluted share) and $0.3 million of charges related to the TimBar Corporation acquisition and integration ($0.2 million after-tax or $0.0 per diluted share).

[8]

Includes $2.8 million of charges related to the closure of a corrugated products facility and a paper products facility ($1.9 million after-tax or $0.02 per diluted share).

Segment Information - Segment S

Segment Information - Segment Sales to External Customers by Product Line (Details) - USD ($) $ in Millions

3 Months Ended

12 Months Ended

Dec. 31, 2017

[1]

Sep. 30, 2017

[2]

Jun. 30, 2017

[3]

Mar. 31, 2017

[4]

Dec. 31, 2016

[5]

Sep. 30, 2016

[6]

Jun. 30, 2016

[7]

Mar. 31, 2016

[8]

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

Revenue from External Customer [Line Items]

Segment sales to external customers

$ 1,684.3

$ 1,640.1

$ 1,584

$ 1,536.5

$ 1,476.6

$ 1,484

$ 1,417.4

$ 1,401

$ 6,444.9

$ 5,779

$ 5,741.7

Packaging

Revenue from External Customer [Line Items]

Segment sales to external customers

5,288.6

4,577.4

4,474.1

Paper

Revenue from External Customer [Line Items]

Segment sales to external customers

1,051.8

1,093.9

1,143.1

Operating Segments | White Papers

Revenue from External Customer [Line Items]

Segment sales to external customers

1,051.8

1,065.8

1,089.6

Operating Segments | Market Pulp

Revenue from External Customer [Line Items]

Segment sales to external customers

28.1

53.5

Operating Segments | Packaging

Revenue from External Customer [Line Items]

Segment sales to external customers

5,312.3

4,584.8

4,477.3

Operating Segments | Paper

Revenue from External Customer [Line Items]

Segment sales to external customers

1,051.8

1,093.9

1,143.1

Operating Segments | Corporate and Other

Revenue from External Customer [Line Items]

Segment sales to external customers

$ 80.8

$ 100.3

$ 121.3

[1]

Includes $7.6 million of income primarily related to the sale of land corresponding to the closure of a corrugated products facility, partially offset by closure costs related to corrugated products facilities, a paper administration facility, and a corporate administration facility ($4.7 million after-tax or $0.05 per diluted share) and $0.9 million of charges related to the Sacramento Container acquisition and integration costs related to other recent acquisitions ($0.5 million after-tax or $0.01 per diluted share), and $8.0 million of charges related to our determination to discontinue production of uncoated free sheet and coated one-side grades at the Wallula, Washington mill in the second quarter of 2018 and convert the No. 3 paper machine to a high-performance 100% virgin kraft linerboard machine ($4.6 million after-tax or $0.05 per diluted share). Also includes $1.8 million of expense related to the write-off of deferred debt issuance costs in connection with the December 2017 debt refinancing ($1.1 million after-tax or $0.01 per diluted share), $2.0 million gain related to the expiration of a repurchase option corresponding to timberland previously sold ($1.2 million after-tax or 0.01 per diluted share), and $122.1 million of estimated income tax benefit related to the enactment in December 2017 of the Tax Cuts and Jobs Act (H.R.1) primarily for the re-measurement of our net deferred tax liability as a result of the reduction in the U.S. corporate income tax rate ($1.29 per diluted share).

[2]

Includes $0.9 million of charges related to the closure of corrugated products facilities, a paper administration facility, and a lump sum settlement of a multiemployer pension plan withdrawal liability for one of our corrugated products facilities ($0.6 million after-tax or $0.01 per diluted share) and $0.5 million of charges related to the Sacramento Container acquisition and integration costs related to other recent acquisitions ($0.3 million after-tax or $0.0 per diluted share). Also includes $25.3 million of charges related to our determination to discontinue production of uncoated free sheet and coated one-side grades at the Wallula, Washington mill in the second quarter of 2018 and convert the No. 3 paper machine to a high-performance 100% virgin kraft linerboard machine ($15.5 million after-tax or $0.16 per diluted share) and $3.3 million of tax expense for the change in value of deferred taxes as a result of an internal legal entity consolidation that will simplify future operating activities ($0.04 per diluted share).

[3]

Includes $0.3 million of charges related to the closure of corrugated products facilities ($0.3 million after-tax or $0.0 per diluted share) and $0.2 million of charges related to TimBar Corporation and Columbus Container integration costs ($0.1 after-tax or $0.0 per diluted share).

[4]

Includes $0.6 million of charges related to the closure of corrugated products facilities and lump sum settlement of a multiemployer pension plan withdrawal liability for one of corrugated products facilities ($0.4 million after-tax or $0.1 per diluted share) and $0.2 million of charges related to TimBar Corporation and Columbus Container integration costs ($0.1 million after-tax or $0.0 per diluted share). Also includes $5.0 million of costs for the property damage and business interruption insurance deductible corresponding to the February 2017 explosion at our DeRidder, Louisiana mill ($3.1 million after-tax or $0.03 per diluted share) and $2.3 million of income related to a working capital adjustment from the April 2015 sale of our Hexacomb corrugated manufacturing operations in Europe and Mexico ($1.4 million after-tax or $0.01 per diluted share).

[5]

Includes $4.5 million of charges related to the closure of a corrugated products facility and a paper products facility ($2.9 million after-tax or $0.03 per diluted share), $2.7 million of costs related to ceased production of softwood market pulp operations at our Wallula, Washington mill and the permanent shutdown of the No. 1 machine ($1.8 million after-tax or $0.02 per diluted share), and $1.2 million of charges related to the TimBar Corporation and Columbus Container acquisitions and integration ($0.8 million after-tax or $0.01 per diluted share).

[6]

Includes $2.0 million of charges related to the closure of a corrugated products facility and a paper products facility ($1.4 million after-tax or $0.02 per diluted share) and $2.9 million of charges related to the TimBar Corporation and Columbus Container acquisitions and integration ($1.9 million after-tax or $0.02 per diluted share).

[7]

Includes $2.6 million of charges related to the closure of corrugated products facilities, a paper products facility, and a lump sum settlement of a multiemployer pension plan withdrawal liability for one of our corrugated products facilities ($1.6 million after-tax or $0.02 per diluted share) and $0.3 million of charges related to the TimBar Corporation acquisition and integration ($0.2 million after-tax or $0.0 per diluted share).

[8]

Includes $2.8 million of charges related to the closure of a corrugated products facility and a paper products facility ($1.9 million after-tax or $0.02 per diluted share).

Segment Information - Analysis

Segment Information - Analysis of Operations by Reportable Segment (Details) - USD ($) $ in Millions		3 Months Ended																12 Months Ended
		Dec. 31, 2017		Sep. 30, 2017	[2]	Jun. 30, 2017	[3]	Mar. 31, 2017	[4]	Dec. 31, 2016		Sep. 30, 2016	[6]	Jun. 30, 2016	[7]	Mar. 31, 2016	[8]	Dec. 31, 2017		Dec. 31, 2016		Dec. 31, 2015
Segment Reporting Information [Line Items]
Net sales		$ 1,684.3	[1]	$ 1,640.1		$ 1,584		$ 1,536.5		$ 1,476.6	[5]	$ 1,484		$ 1,417.4		$ 1,401		$ 6,444.9		$ 5,779		$ 5,741.7
Operating Income (Loss)		252	[1]	$ 242.3		$ 233.8		$ 203.1		192.9	[5]	$ 206.4		$ 200.2		$ 180.8		931.2		780.3		750
Interest expense, net																		(102.6)	[9]	(91.8)		(85.5)
Segment income (loss) from operations																		828.6		688.5		664.5
Depreciation, Amortization, and Depletion																		391.4		358		356.5
Capital Expenditures	[10]																	343		274.3		314.5
Assets		6,197.5								5,777								6,197.5		5,777		5,272.3
Intersegment Eliminations
Segment Reporting Information [Line Items]
Net sales																		(148.4)		(146.6)		(137)
Segment Reconciling Items
Segment Reporting Information [Line Items]
Net sales																		(148.4)		(146.6)		(137)
Packaging
Segment Reporting Information [Line Items]
Net sales																		5,288.6		4,577.4		4,474.1
Operating Income (Loss)																		943.7	[11]	711	[12]	714.9	[13]
Depreciation, Amortization, and Depletion																		317.5		293.3		297.3
Capital Expenditures	[10]																	305.1		239.9		250.3
Assets		4,933.6								4,530.5								4,933.6		4,530.5		4,027.9
Packaging | Intersegment Eliminations
Segment Reporting Information [Line Items]
Net sales																		23.7		7.4		3.2
Packaging | Operating Segments
Segment Reporting Information [Line Items]
Net sales																		5,312.3		4,584.8		4,477.3
Paper
Segment Reporting Information [Line Items]
Net sales																		1,051.8		1,093.9		1,143.1
Operating Income (Loss)																		61.5	[14]	138.1	[15]	112.5	[16]
Depreciation, Amortization, and Depletion																		67.6		59.6		54.9
Capital Expenditures	[10]																	22.6		31.6		58.5
Assets		945.2								946.2								945.2		946.2		976.5
Paper | Operating Segments
Segment Reporting Information [Line Items]
Net sales																		1,051.8		1,093.9		1,143.1
Corporate and Other
Segment Reporting Information [Line Items]
Net sales																		104.5		107.7		124.5
Operating Income (Loss)																		(74)	[17]	(68.9)	[18]	(77.4)	[19]
Depreciation, Amortization, and Depletion																		6.3		5.1		4.3
Capital Expenditures	[10]																	15.3		2.8		5.7
Assets		$ 318.7								$ 300.3								318.7		300.3		267.9
Corporate and Other | Intersegment Eliminations
Segment Reporting Information [Line Items]
Net sales																		124.7		139.2		133.8
Corporate and Other | Operating Segments
Segment Reporting Information [Line Items]
Net sales																		$ 229.2		$ 246.9		$ 258.3
[1]	Includes $7.6 million of income primarily related to the sale of land corresponding to the closure of a corrugated products facility, partially offset by closure costs related to corrugated products facilities, a paper administration facility, and a corporate administration facility ($4.7 million after-tax or $0.05 per diluted share) and $0.9 million of charges related to the Sacramento Container acquisition and integration costs related to other recent acquisitions ($0.5 million after-tax or $0.01 per diluted share), and $8.0 million of charges related to our determination to discontinue production of uncoated free sheet and coated one-side grades at the Wallula, Washington mill in the second quarter of 2018 and convert the No. 3 paper machine to a high-performance 100% virgin kraft linerboard machine ($4.6 million after-tax or $0.05 per diluted share). Also includes $1.8 million of expense related to the write-off of deferred debt issuance costs in connection with the December 2017 debt refinancing ($1.1 million after-tax or $0.01 per diluted share), $2.0 million gain related to the expiration of a repurchase option corresponding to timberland previously sold ($1.2 million after-tax or 0.01 per diluted share), and $122.1 million of estimated income tax benefit related to the enactment in December 2017 of the Tax Cuts and Jobs Act (H.R.1) primarily for the re-measurement of our net deferred tax liability as a result of the reduction in the U.S. corporate income tax rate ($1.29 per diluted share).
[2]	Includes $0.9 million of charges related to the closure of corrugated products facilities, a paper administration facility, and a lump sum settlement of a multiemployer pension plan withdrawal liability for one of our corrugated products facilities ($0.6 million after-tax or $0.01 per diluted share) and $0.5 million of charges related to the Sacramento Container acquisition and integration costs related to other recent acquisitions ($0.3 million after-tax or $0.0 per diluted share). Also includes $25.3 million of charges related to our determination to discontinue production of uncoated free sheet and coated one-side grades at the Wallula, Washington mill in the second quarter of 2018 and convert the No. 3 paper machine to a high-performance 100% virgin kraft linerboard machine ($15.5 million after-tax or $0.16 per diluted share) and $3.3 million of tax expense for the change in value of deferred taxes as a result of an internal legal entity consolidation that will simplify future operating activities ($0.04 per diluted share).
[3]	Includes $0.3 million of charges related to the closure of corrugated products facilities ($0.3 million after-tax or $0.0 per diluted share) and $0.2 million of charges related to TimBar Corporation and Columbus Container integration costs ($0.1 after-tax or $0.0 per diluted share).
[4]	Includes $0.6 million of charges related to the closure of corrugated products facilities and lump sum settlement of a multiemployer pension plan withdrawal liability for one of corrugated products facilities ($0.4 million after-tax or $0.1 per diluted share) and $0.2 million of charges related to TimBar Corporation and Columbus Container integration costs ($0.1 million after-tax or $0.0 per diluted share). Also includes $5.0 million of costs for the property damage and business interruption insurance deductible corresponding to the February 2017 explosion at our DeRidder, Louisiana mill ($3.1 million after-tax or $0.03 per diluted share) and $2.3 million of income related to a working capital adjustment from the April 2015 sale of our Hexacomb corrugated manufacturing operations in Europe and Mexico ($1.4 million after-tax or $0.01 per diluted share).
[5]	Includes $4.5 million of charges related to the closure of a corrugated products facility and a paper products facility ($2.9 million after-tax or $0.03 per diluted share), $2.7 million of costs related to ceased production of softwood market pulp operations at our Wallula, Washington mill and the permanent shutdown of the No. 1 machine ($1.8 million after-tax or $0.02 per diluted share), and $1.2 million of charges related to the TimBar Corporation and Columbus Container acquisitions and integration ($0.8 million after-tax or $0.01 per diluted share).
[6]	Includes $2.0 million of charges related to the closure of a corrugated products facility and a paper products facility ($1.4 million after-tax or $0.02 per diluted share) and $2.9 million of charges related to the TimBar Corporation and Columbus Container acquisitions and integration ($1.9 million after-tax or $0.02 per diluted share).
[7]	Includes $2.6 million of charges related to the closure of corrugated products facilities, a paper products facility, and a lump sum settlement of a multiemployer pension plan withdrawal liability for one of our corrugated products facilities ($1.6 million after-tax or $0.02 per diluted share) and $0.3 million of charges related to the TimBar Corporation acquisition and integration ($0.2 million after-tax or $0.0 per diluted share).
[8]	Includes $2.8 million of charges related to the closure of a corrugated products facility and a paper products facility ($1.9 million after-tax or $0.02 per diluted share).
[9]	Includes $1.8 million of expense related to the write-off of deferred debt issuance costs in connection with the December 2017 debt refinancing.
[10]	Includes “Additions to property, plant, and equipment” and excludes cash used for “Acquisitions of businesses, net of cash acquired” as reported on our Consolidated Statements of Cash Flows.
[11]	(a)Includes the following: $7.2 million of income, net, primarily related to the sale of land corresponding to the closure of a corrugated products facility, partially offset by closure costs related to corrugated products facilities, and a lump sum settlement of a multiemployer pension plan withdrawal liability for one of our corrugated products facilities. $1.7 million of charges related to the Sacramento Container acquisition and integration costs related to other recent acquisitions. $2.0 million gain related to the expiration of a repurchase option corresponding to timberland previously sold. $1.6 million of income related to a working capital adjustment from the April 2015 sale of our Hexacomb corrugated manufacturing operations in Europe and Mexico. $5.0 million of costs for the property damage and business interruption insurance deductible corresponding to the February 2017 explosion at our DeRidder, Louisiana mill.
[12]	Includes $10.2 million of closure costs related to corrugated product facilities and a lump sum settlement of a multiemployer pension plan withdrawal liability for one of our corrugated products facilities and $4.2 million of acquisition-related costs for the TimBar Corporation and Columbus Container acquisitions.
[13]	Includes net charges of $2.0 million primarily related to restructuring activities at our mill in DeRidder, Louisiana and $4.1 million of Boise acquisition integration-related and other costs.
[14]	Includes $33.4 million of charges related to our determination to discontinue production of uncoated free sheet and coated one-side grades at the Wallula, Washington mill in the second quarter of 2018 and convert the No. 3 paper machine to a high-performance 100% virgin kraft linerboard machine and $0.4 million of charges related to the closure costs of a paper administration facility.
[15]	Includes $2.7 million of costs related to ceased softwood market pulp operations at our Wallula, Washington mill and the permanent shut down of the No.1 machine and $1.7 million of closure costs related to a paper products facility.
[16]	In September 2015, we sold the remaining land, buildings, and equipment at our paper mill site in St. Helens, Oregon where we ceased paper production in December 2012. We recorded a $6.7 million gain on the sale.
[17]	Includes $1.0 million of charges related to the closure costs of a corporate administration facility and $0.7 million of income related to a working capital adjustment from the April 2015 sale of our Hexacomb corrugated manufacturing operations in Europe and Mexico.
[18]	Includes $0.3 million of acquisition-related costs related to the TimBar Corporation acquisition.
[19]	Includes $9.3 million of Boise acquisition integration-related and other costs. These costs primarily relate to professional fees, severance, retention, relocation, travel, and other integration-related costs.

Segment Information (Parentheti

Segment Information (Parenthetical) (Details) - USD ($) $ in Millions

1 Months Ended

3 Months Ended

12 Months Ended

Sep. 30, 2015

Dec. 31, 2017

Sep. 30, 2017

Jun. 30, 2017

Mar. 31, 2017

Dec. 31, 2016

Sep. 30, 2016

Jun. 30, 2016

Mar. 31, 2016

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

Segment Reporting Information [Line Items]

Operating Income (Loss)

$ 252

[1]

$ 242.3

[2]

$ 233.8

[3]

$ 203.1

[4]

$ 192.9

[5]

$ 206.4

[6]

$ 200.2

[7]

$ 180.8

[8]

$ 931.2

$ 780.3

$ 750

Acquisition and integration related costs

[9],[10],[11]

0.8

3.3

12.9

Hexacomb working capital adjustment

[12]

2.3

Interest expense, net

(102.6)

[13]

(91.8)

(85.5)

Write-Off of Deferred Financing Costs

Segment Reporting Information [Line Items]

Interest expense, net

1.8

(1.8)

TimBar Corporation

Segment Reporting Information [Line Items]

Operating Income (Loss)

(0.2)

0.2

(1.2)

(2.9)

(0.3)

Mill at St. Helens, Oregon

Segment Reporting Information [Line Items]

Gain on sale of land, buildings, and equipment

$ 6.7

6.7

[14]

Deridder Mill

Segment Reporting Information [Line Items]

Restructuring

[15]

7.1

Wallula, Washington Mill

Segment Reporting Information [Line Items]

Operating Income (Loss)

$ (8)

$ (25.3)

(2.7)

Restructuring charges

$ 23.1

High-performance of virgin kraft linerboard machine percentage

100.00%

100.00%

100.00%

Facilities closure costs

[16]

0.6

Restructuring

[17]

$ (23.1)

Packaging

Segment Reporting Information [Line Items]

Operating Income (Loss)

943.7

[18]

711

[19]

714.9

[20]

Acquisition and integration related costs

1.7

Facilities closure costs

10.2

Packaging | TimBar Corporation

Segment Reporting Information [Line Items]

Acquisition-related costs

4.2

Packaging | Boise Inc.

Segment Reporting Information [Line Items]

Operating Income (Loss)

4.1

Packaging | Deridder Mill

Segment Reporting Information [Line Items]

Property damages and business interruption insurance

$ 5

5

Packaging | Hexacomb Europe and Mexico

Segment Reporting Information [Line Items]

Acquisition and integration related costs

1.6

Paper

Segment Reporting Information [Line Items]

Operating Income (Loss)

61.5

[21]

138.1

[22]

112.5

[23]

Facilities closure costs

0.4

1.7

Paper | Wallula, Washington Mill

Segment Reporting Information [Line Items]

Restructuring charges

$ 33.4

High-performance of virgin kraft linerboard machine percentage

100.00%

Restructuring

2.7

Corporate and Other

Segment Reporting Information [Line Items]

Operating Income (Loss)

$ (74)

[24]

(68.9)

[25]

(77.4)

[26]

Facilities closure costs

1

Corporate and Other | TimBar Corporation

Segment Reporting Information [Line Items]

Acquisition-related costs

$ 0.3

Corporate and Other | Boise Inc.

Segment Reporting Information [Line Items]

Operating Income (Loss)

9.3

Corporate and Other | Hexacomb Europe and Mexico

Segment Reporting Information [Line Items]

Hexacomb working capital adjustment

0.7

Corrugated Products Facility Closure

Segment Reporting Information [Line Items]

Operating Income (Loss)

$ 7.6

$ (0.9)

$ (0.3)

$ (0.6)

$ (4.5)

$ (2)

$ (2.6)

$ (2.8)

Corrugated Products Facility Closure | Packaging

Segment Reporting Information [Line Items]

Operating Income (Loss)

7.2

Timberland | Packaging

Segment Reporting Information [Line Items]

Operating Income (Loss)

$ 2

Other Restructuring | Packaging

Segment Reporting Information [Line Items]

Operating Income (Loss)

$ 2

[1]

Includes $7.6 million of income primarily related to the sale of land corresponding to the closure of a corrugated products facility, partially offset by closure costs related to corrugated products facilities, a paper administration facility, and a corporate administration facility ($4.7 million after-tax or $0.05 per diluted share) and $0.9 million of charges related to the Sacramento Container acquisition and integration costs related to other recent acquisitions ($0.5 million after-tax or $0.01 per diluted share), and $8.0 million of charges related to our determination to discontinue production of uncoated free sheet and coated one-side grades at the Wallula, Washington mill in the second quarter of 2018 and convert the No. 3 paper machine to a high-performance 100% virgin kraft linerboard machine ($4.6 million after-tax or $0.05 per diluted share). Also includes $1.8 million of expense related to the write-off of deferred debt issuance costs in connection with the December 2017 debt refinancing ($1.1 million after-tax or $0.01 per diluted share), $2.0 million gain related to the expiration of a repurchase option corresponding to timberland previously sold ($1.2 million after-tax or 0.01 per diluted share), and $122.1 million of estimated income tax benefit related to the enactment in December 2017 of the Tax Cuts and Jobs Act (H.R.1) primarily for the re-measurement of our net deferred tax liability as a result of the reduction in the U.S. corporate income tax rate ($1.29 per diluted share).

[2]

Includes $0.9 million of charges related to the closure of corrugated products facilities, a paper administration facility, and a lump sum settlement of a multiemployer pension plan withdrawal liability for one of our corrugated products facilities ($0.6 million after-tax or $0.01 per diluted share) and $0.5 million of charges related to the Sacramento Container acquisition and integration costs related to other recent acquisitions ($0.3 million after-tax or $0.0 per diluted share). Also includes $25.3 million of charges related to our determination to discontinue production of uncoated free sheet and coated one-side grades at the Wallula, Washington mill in the second quarter of 2018 and convert the No. 3 paper machine to a high-performance 100% virgin kraft linerboard machine ($15.5 million after-tax or $0.16 per diluted share) and $3.3 million of tax expense for the change in value of deferred taxes as a result of an internal legal entity consolidation that will simplify future operating activities ($0.04 per diluted share).

[3]

Includes $0.3 million of charges related to the closure of corrugated products facilities ($0.3 million after-tax or $0.0 per diluted share) and $0.2 million of charges related to TimBar Corporation and Columbus Container integration costs ($0.1 after-tax or $0.0 per diluted share).

[4]

Includes $0.6 million of charges related to the closure of corrugated products facilities and lump sum settlement of a multiemployer pension plan withdrawal liability for one of corrugated products facilities ($0.4 million after-tax or $0.1 per diluted share) and $0.2 million of charges related to TimBar Corporation and Columbus Container integration costs ($0.1 million after-tax or $0.0 per diluted share). Also includes $5.0 million of costs for the property damage and business interruption insurance deductible corresponding to the February 2017 explosion at our DeRidder, Louisiana mill ($3.1 million after-tax or $0.03 per diluted share) and $2.3 million of income related to a working capital adjustment from the April 2015 sale of our Hexacomb corrugated manufacturing operations in Europe and Mexico ($1.4 million after-tax or $0.01 per diluted share).

[5]

Includes $4.5 million of charges related to the closure of a corrugated products facility and a paper products facility ($2.9 million after-tax or $0.03 per diluted share), $2.7 million of costs related to ceased production of softwood market pulp operations at our Wallula, Washington mill and the permanent shutdown of the No. 1 machine ($1.8 million after-tax or $0.02 per diluted share), and $1.2 million of charges related to the TimBar Corporation and Columbus Container acquisitions and integration ($0.8 million after-tax or $0.01 per diluted share).

[6]

Includes $2.0 million of charges related to the closure of a corrugated products facility and a paper products facility ($1.4 million after-tax or $0.02 per diluted share) and $2.9 million of charges related to the TimBar Corporation and Columbus Container acquisitions and integration ($1.9 million after-tax or $0.02 per diluted share).

[7]

Includes $2.6 million of charges related to the closure of corrugated products facilities, a paper products facility, and a lump sum settlement of a multiemployer pension plan withdrawal liability for one of our corrugated products facilities ($1.6 million after-tax or $0.02 per diluted share) and $0.3 million of charges related to the TimBar Corporation acquisition and integration ($0.2 million after-tax or $0.0 per diluted share).

[8]

Includes $2.8 million of charges related to the closure of a corrugated products facility and a paper products facility ($1.9 million after-tax or $0.02 per diluted share).

[9]

For 2015, includes Boise acquisition integration-related and other costs, which primarily relate to severance, retention, travel, and professional fees.

[10]

For 2016, includes charges related to the acquisition and integration of TimBar Corporation.

[11]

For 2017, includes charges related to the Sacramento Container Corporation acquisition and integration costs related to other recent acquisitions.

[12]

Includes income related to a working capital adjustment from the April 2015 sale of our Hexacomb corrugated manufacturing operations in Europe and Mexico.

[13]

Includes $1.8 million of expense related to the write-off of deferred debt issuance costs in connection with the December 2017 debt refinancing.

[14]

Includes a gain related to the sale of the remaining land, buildings, and equipment at our paper mill site in St. Helens, Oregon where we ceased paper production in December 2012.

[15]

Includes $7.1 million of income from vendor settlements related to our restructuring activities at our DeRidder, Louisiana mill.

[16]

Includes costs related to ceased softwood market pulp operations at our Wallula, Washington mill and the permanent shutdown of the No. 1 machine.

[17]

Includes $23.1 million of charges related to our determination to discontinue production of uncoated free sheet and coated one-side grades at the Wallula, Washington mill in the second quarter of 2018 and convert the No. 3 paper machine to a high-performance 100% virgin kraft linerboard machine.

[18]

(a)Includes the following: $7.2 million of income, net, primarily related to the sale of land corresponding to the closure of a corrugated products facility, partially offset by closure costs related to corrugated products facilities, and a lump sum settlement of a multiemployer pension plan withdrawal liability for one of our corrugated products facilities. $1.7 million of charges related to the Sacramento Container acquisition and integration costs related to other recent acquisitions. $2.0 million gain related to the expiration of a repurchase option corresponding to timberland previously sold. $1.6 million of income related to a working capital adjustment from the April 2015 sale of our Hexacomb corrugated manufacturing operations in Europe and Mexico. $5.0 million of costs for the property damage and business interruption insurance deductible corresponding to the February 2017 explosion at our DeRidder, Louisiana mill.

[19]

Includes $10.2 million of closure costs related to corrugated product facilities and a lump sum settlement of a multiemployer pension plan withdrawal liability for one of our corrugated products facilities and $4.2 million of acquisition-related costs for the TimBar Corporation and Columbus Container acquisitions.

[20]

Includes net charges of $2.0 million primarily related to restructuring activities at our mill in DeRidder, Louisiana and $4.1 million of Boise acquisition integration-related and other costs.

[21]

Includes $33.4 million of charges related to our determination to discontinue production of uncoated free sheet and coated one-side grades at the Wallula, Washington mill in the second quarter of 2018 and convert the No. 3 paper machine to a high-performance 100% virgin kraft linerboard machine and $0.4 million of charges related to the closure costs of a paper administration facility.

[22]

Includes $2.7 million of costs related to ceased softwood market pulp operations at our Wallula, Washington mill and the permanent shut down of the No.1 machine and $1.7 million of closure costs related to a paper products facility.

[23]

In September 2015, we sold the remaining land, buildings, and equipment at our paper mill site in St. Helens, Oregon where we ceased paper production in December 2012. We recorded a $6.7 million gain on the sale.

[24]

Includes $1.0 million of charges related to the closure costs of a corporate administration facility and $0.7 million of income related to a working capital adjustment from the April 2015 sale of our Hexacomb corrugated manufacturing operations in Europe and Mexico.

[25]

Includes $0.3 million of acquisition-related costs related to the TimBar Corporation acquisition.

[26]

Includes $9.3 million of Boise acquisition integration-related and other costs. These costs primarily relate to professional fees, severance, retention, relocation, travel, and other integration-related costs.

Commitments, Guarantees, Ind102

Commitments, Guarantees, Indemnifications, and Legal Proceedings - Additional Information (Details)	12 Months Ended
	Dec. 31, 2017USD ($)a	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Feb. 08, 2017USD ($)
Schedule Of Commitments And Contingencies [Line Items]
Capital commitments	$ 281,300,000	$ 94,700,000
Area leased under timberland cutting rights (acres) | a	75,000
Average lease renewal term	6 years
Total lease expense	$ 100,600,000	88,300,000	$ 87,900,000
Sublease rental income	0
Capital lease obligations	20,300,000	21,600,000
Interest paid, capital lease obligations	1,400,000	1,500,000	1,600,000
Purchases during period under purchase agreements	339,100,000	362,000,000	$ 299,600,000
Environmental reserve	31,500,000
Environmental liabilities and asset retirement obligations	$ 4,000,000	$ 6,400,000
DeRidder, Louisiana
Schedule Of Commitments And Contingencies [Line Items]
Loss contingency, period of occurrence	February 8, 2017
Liability insurance				$ 1,000,000
Property damages and business interruption insurance				$ 5,000,000
DeRidder, Louisiana | Other Expense, Net
Schedule Of Commitments And Contingencies [Line Items]
Claim with insurance carrier	$ 17,000,000
Asset Retirement Obligation
Schedule Of Commitments And Contingencies [Line Items]
Environmental reserve	24,000,000
Environmental Contingencies
Schedule Of Commitments And Contingencies [Line Items]
Environmental reserve	7,500,000
Other Long-Term Liabilities
Schedule Of Commitments And Contingencies [Line Items]
Environmental reserve	$ 27,500,000
Maximum
Schedule Of Commitments And Contingencies [Line Items]
Remaining lease term	14 years
Purchase commitments term, years	22 years
Minimum
Schedule Of Commitments And Contingencies [Line Items]
Purchase commitments term, years	1 year

Commitments, Guarantees, Ind103

Commitments, Guarantees, Indemnifications, and Legal Proceedings - Schedule of Minimum Lease Payments Under Non-Cancelable Operating Leases (Details) $ in Millions	Dec. 31, 2017USD ($)
Leases Operating [Abstract]
2,018	$ 63.8
2,019	54
2,020	41.1
2,021	29.6
2,022	19.1
Thereafter	56.2
Total	$ 263.8

Commitments, Guarantees, Ind104

Commitments, Guarantees, Indemnifications, and Legal Proceedings - Schedule of Assets Held Under Capital Lease Obligations (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Capital Leased Assets [Line Items]
Total capital lease assets, Gross	$ 28.8	$ 28.8
Less accumulated amortization	(15.2)	(13.7)
Total capital lease assets, net	13.6	15.1
Buildings
Capital Leased Assets [Line Items]
Total capital lease assets, Gross	0.3	0.3
Machinery and Equipment
Capital Leased Assets [Line Items]
Total capital lease assets, Gross	$ 28.5	$ 28.5

Commitments, Guarantees, Ind105

Commitments, Guarantees, Indemnifications, and Legal Proceedings - Schedule of Future Minimum Payments Under Capitalized Leases (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Capital Leases Future Minimum Payments Due [Abstract]
2,018	$ 2.7
2,019	2.7
2,020	2.7
2,021	2.7
2,022	2.7
Thereafter	15
Total minimum capital lease payments	28.5
Less amounts representing interest	(8.2)
Present value of net minimum capital lease payments	20.3
Less current maturities of capital lease obligations	(1.3)	$ (1.3)
Total long-term capital lease obligations	$ 19	$ 20.3

Commitments, Guarantees, Ind106

Commitments, Guarantees, Indemnifications, and Legal Proceedings - Schedule of Purchase Commitments (Details) $ in Millions	Dec. 31, 2017USD ($)
Commitments And Contingencies Disclosure [Abstract]
2,018	$ 79.8
2,019	54.4
2,020	45.6
2,021	43
2,022	42.5
Thereafter	159
Total	$ 424.3

Quarterly Financial Data - Summ

Quarterly Financial Data - Summary of Quarterly Financial Data (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended																12 Months Ended
	Dec. 31, 2017	[1]	Sep. 30, 2017	[2]	Jun. 30, 2017	[3]	Mar. 31, 2017	[4]	Dec. 31, 2016	[5]	Sep. 30, 2016	[6]	Jun. 30, 2016	[7]	Mar. 31, 2016	[8]	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Quarterly Financial Information Disclosure [Abstract]
Net sales	$ 1,684.3		$ 1,640.1		$ 1,584		$ 1,536.5		$ 1,476.6		$ 1,484		$ 1,417.4		$ 1,401		$ 6,444.9	$ 5,779	$ 5,741.7
Gross profit	371.7		397.3		364.6		338.5		327.1		329.5		320.1		299		1,472.2	1,275.7	1,208
Operating Income (Loss)	252		242.3		233.8		203.1		192.9		206.4		200.2		180.8		931.2	780.3	750
Net income	$ 268.9		$ 139.1		$ 143.2		$ 117.4		$ 110.6		$ 119.4		$ 115.9		$ 103.7		$ 668.6	$ 449.6	$ 436.8
Basic	$ 2.85		$ 1.47		$ 1.52		$ 1.25		$ 1.17		$ 1.27		$ 1.23		$ 1.09		$ 7.09	$ 4.76	$ 4.47
Diluted	2.84		1.47		1.52		1.24		1.17		1.26		1.23		1.09		7.07	4.75	$ 4.47
Stock price - high	121.38		119.43		113.52		96.87		88.41		82.77		71.31		62.67		121.38	88.41
Stock price - low	$ 108.49		$ 105.81		$ 89.73		$ 84.01		$ 78.03		$ 65.12		$ 58.44		$ 44.32		$ 84.01	$ 44.32
[1]	Includes $7.6 million of income primarily related to the sale of land corresponding to the closure of a corrugated products facility, partially offset by closure costs related to corrugated products facilities, a paper administration facility, and a corporate administration facility ($4.7 million after-tax or $0.05 per diluted share) and $0.9 million of charges related to the Sacramento Container acquisition and integration costs related to other recent acquisitions ($0.5 million after-tax or $0.01 per diluted share), and $8.0 million of charges related to our determination to discontinue production of uncoated free sheet and coated one-side grades at the Wallula, Washington mill in the second quarter of 2018 and convert the No. 3 paper machine to a high-performance 100% virgin kraft linerboard machine ($4.6 million after-tax or $0.05 per diluted share). Also includes $1.8 million of expense related to the write-off of deferred debt issuance costs in connection with the December 2017 debt refinancing ($1.1 million after-tax or $0.01 per diluted share), $2.0 million gain related to the expiration of a repurchase option corresponding to timberland previously sold ($1.2 million after-tax or 0.01 per diluted share), and $122.1 million of estimated income tax benefit related to the enactment in December 2017 of the Tax Cuts and Jobs Act (H.R.1) primarily for the re-measurement of our net deferred tax liability as a result of the reduction in the U.S. corporate income tax rate ($1.29 per diluted share).
[2]	Includes $0.9 million of charges related to the closure of corrugated products facilities, a paper administration facility, and a lump sum settlement of a multiemployer pension plan withdrawal liability for one of our corrugated products facilities ($0.6 million after-tax or $0.01 per diluted share) and $0.5 million of charges related to the Sacramento Container acquisition and integration costs related to other recent acquisitions ($0.3 million after-tax or $0.0 per diluted share). Also includes $25.3 million of charges related to our determination to discontinue production of uncoated free sheet and coated one-side grades at the Wallula, Washington mill in the second quarter of 2018 and convert the No. 3 paper machine to a high-performance 100% virgin kraft linerboard machine ($15.5 million after-tax or $0.16 per diluted share) and $3.3 million of tax expense for the change in value of deferred taxes as a result of an internal legal entity consolidation that will simplify future operating activities ($0.04 per diluted share).
[3]	Includes $0.3 million of charges related to the closure of corrugated products facilities ($0.3 million after-tax or $0.0 per diluted share) and $0.2 million of charges related to TimBar Corporation and Columbus Container integration costs ($0.1 after-tax or $0.0 per diluted share).
[4]	Includes $0.6 million of charges related to the closure of corrugated products facilities and lump sum settlement of a multiemployer pension plan withdrawal liability for one of corrugated products facilities ($0.4 million after-tax or $0.1 per diluted share) and $0.2 million of charges related to TimBar Corporation and Columbus Container integration costs ($0.1 million after-tax or $0.0 per diluted share). Also includes $5.0 million of costs for the property damage and business interruption insurance deductible corresponding to the February 2017 explosion at our DeRidder, Louisiana mill ($3.1 million after-tax or $0.03 per diluted share) and $2.3 million of income related to a working capital adjustment from the April 2015 sale of our Hexacomb corrugated manufacturing operations in Europe and Mexico ($1.4 million after-tax or $0.01 per diluted share).
[5]	Includes $4.5 million of charges related to the closure of a corrugated products facility and a paper products facility ($2.9 million after-tax or $0.03 per diluted share), $2.7 million of costs related to ceased production of softwood market pulp operations at our Wallula, Washington mill and the permanent shutdown of the No. 1 machine ($1.8 million after-tax or $0.02 per diluted share), and $1.2 million of charges related to the TimBar Corporation and Columbus Container acquisitions and integration ($0.8 million after-tax or $0.01 per diluted share).
[6]	Includes $2.0 million of charges related to the closure of a corrugated products facility and a paper products facility ($1.4 million after-tax or $0.02 per diluted share) and $2.9 million of charges related to the TimBar Corporation and Columbus Container acquisitions and integration ($1.9 million after-tax or $0.02 per diluted share).
[7]	Includes $2.6 million of charges related to the closure of corrugated products facilities, a paper products facility, and a lump sum settlement of a multiemployer pension plan withdrawal liability for one of our corrugated products facilities ($1.6 million after-tax or $0.02 per diluted share) and $0.3 million of charges related to the TimBar Corporation acquisition and integration ($0.2 million after-tax or $0.0 per diluted share).
[8]	Includes $2.8 million of charges related to the closure of a corrugated products facility and a paper products facility ($1.9 million after-tax or $0.02 per diluted share).

Quarterly Financial Data - S108

Quarterly Financial Data - Summary of Quarterly Financial Data (Parenthetical) (Details) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended																12 Months Ended
		Dec. 31, 2017		Sep. 30, 2017		Jun. 30, 2017		Mar. 31, 2017		Dec. 31, 2016		Sep. 30, 2016		Jun. 30, 2016		Mar. 31, 2016		Dec. 31, 2017		Dec. 31, 2016		Dec. 31, 2015
Quarterly Financial Data [Line Items]
Operating Income (Loss)		$ 252	[1]	$ 242.3	[2]	$ 233.8	[3]	$ 203.1	[4]	$ 192.9	[5]	$ 206.4	[6]	$ 200.2	[7]	$ 180.8	[8]	$ 931.2		$ 780.3		$ 750
Decrease (Increase) in net income per diluted share				$ (0.04)
Hexacomb working capital adjustment	[9]																	2.3
Tax expense due to change in value of deferred taxes				$ 3.3
Interest expense, net																		(102.6)	[10]	(91.8)		(85.5)
Gain on expiration of repurchase option	[11]																	2
Write-off of Deferred Debt Issuance Costs
Quarterly Financial Data [Line Items]
Decrease (Increase) in net income		$ (1.1)
Decrease (Increase) in net income per diluted share		$ (0.01)
Interest expense, net		$ 1.8																$ (1.8)
U.S. federal
Quarterly Financial Data [Line Items]
Decrease (Increase) in net income per diluted share		$ (1.29)
Income tax benefit related to enactment of Tax Cuts and Jobs Act		$ 122.1
Wallula, Washington Mill
Quarterly Financial Data [Line Items]
Operating Income (Loss)		(8)		(25.3)						(2.7)
Decrease (Increase) in net income		$ (4.6)		$ (15.5)						$ (1.8)
Decrease (Increase) in net income per diluted share		$ (0.05)		$ (0.16)						$ (0.02)
High-performance of virgin kraft linerboard machine percentage		100.00%		100.00%														100.00%
Timberland
Quarterly Financial Data [Line Items]
Decrease (Increase) in net income		$ (1.2)
Decrease (Increase) in net income per diluted share		$ (0.01)
Gain on expiration of repurchase option		$ 2
Corrugated Products Facility Closure
Quarterly Financial Data [Line Items]
Operating Income (Loss)		7.6		$ (0.9)		(0.3)		(0.6)		$ (4.5)		(2)		(2.6)		(2.8)
Decrease (Increase) in net income		$ (4.7)		$ (0.6)		$ (0.3)		$ (0.4)		$ (2.9)		$ (1.4)		$ (1.6)		$ (1.9)
Decrease (Increase) in net income per diluted share		$ (0.05)		$ (0.01)		$ 0		$ (0.1)		$ (0.03)		$ (0.02)		$ (0.02)		$ (0.02)
TimBar Corporation
Quarterly Financial Data [Line Items]
Operating Income (Loss)						$ (0.2)		$ 0.2		$ (1.2)		$ (2.9)		$ (0.3)
Decrease (Increase) in net income						$ (0.1)		$ (0.1)		$ (0.8)		$ (1.9)		$ (0.2)
Decrease (Increase) in net income per diluted share						$ 0		$ 0		$ (0.01)		$ (0.02)		$ 0
Sacramento Container Corporation
Quarterly Financial Data [Line Items]
Operating Income (Loss)		$ (0.9)		$ (0.5)
Decrease (Increase) in net income		$ (0.5)		$ (0.3)
Decrease (Increase) in net income per diluted share		$ (0.01)		$ 0
DeRidder, Louisiana
Quarterly Financial Data [Line Items]
Decrease (Increase) in net income								$ (3.1)
Decrease (Increase) in net income per diluted share								$ (0.03)
Hexacomb Europe and Mexico
Quarterly Financial Data [Line Items]
Decrease (Increase) in net income								$ (1.4)
Decrease (Increase) in net income per diluted share								$ (0.01)
Packaging
Quarterly Financial Data [Line Items]
Operating Income (Loss)																		$ 943.7	[12]	$ 711	[13]	$ 714.9	[14]
Packaging | Corrugated Products Facility Closure
Quarterly Financial Data [Line Items]
Operating Income (Loss)																		$ 7.2
Packaging | DeRidder, Louisiana
Quarterly Financial Data [Line Items]
DeRidder mill incident								$ (5)
Packaging And Corporate And Other | DeRidder, Louisiana
Quarterly Financial Data [Line Items]
Hexacomb working capital adjustment								$ 2.3
[1]	Includes $7.6 million of income primarily related to the sale of land corresponding to the closure of a corrugated products facility, partially offset by closure costs related to corrugated products facilities, a paper administration facility, and a corporate administration facility ($4.7 million after-tax or $0.05 per diluted share) and $0.9 million of charges related to the Sacramento Container acquisition and integration costs related to other recent acquisitions ($0.5 million after-tax or $0.01 per diluted share), and $8.0 million of charges related to our determination to discontinue production of uncoated free sheet and coated one-side grades at the Wallula, Washington mill in the second quarter of 2018 and convert the No. 3 paper machine to a high-performance 100% virgin kraft linerboard machine ($4.6 million after-tax or $0.05 per diluted share). Also includes $1.8 million of expense related to the write-off of deferred debt issuance costs in connection with the December 2017 debt refinancing ($1.1 million after-tax or $0.01 per diluted share), $2.0 million gain related to the expiration of a repurchase option corresponding to timberland previously sold ($1.2 million after-tax or 0.01 per diluted share), and $122.1 million of estimated income tax benefit related to the enactment in December 2017 of the Tax Cuts and Jobs Act (H.R.1) primarily for the re-measurement of our net deferred tax liability as a result of the reduction in the U.S. corporate income tax rate ($1.29 per diluted share).
[2]	Includes $0.9 million of charges related to the closure of corrugated products facilities, a paper administration facility, and a lump sum settlement of a multiemployer pension plan withdrawal liability for one of our corrugated products facilities ($0.6 million after-tax or $0.01 per diluted share) and $0.5 million of charges related to the Sacramento Container acquisition and integration costs related to other recent acquisitions ($0.3 million after-tax or $0.0 per diluted share). Also includes $25.3 million of charges related to our determination to discontinue production of uncoated free sheet and coated one-side grades at the Wallula, Washington mill in the second quarter of 2018 and convert the No. 3 paper machine to a high-performance 100% virgin kraft linerboard machine ($15.5 million after-tax or $0.16 per diluted share) and $3.3 million of tax expense for the change in value of deferred taxes as a result of an internal legal entity consolidation that will simplify future operating activities ($0.04 per diluted share).
[3]	Includes $0.3 million of charges related to the closure of corrugated products facilities ($0.3 million after-tax or $0.0 per diluted share) and $0.2 million of charges related to TimBar Corporation and Columbus Container integration costs ($0.1 after-tax or $0.0 per diluted share).
[4]	Includes $0.6 million of charges related to the closure of corrugated products facilities and lump sum settlement of a multiemployer pension plan withdrawal liability for one of corrugated products facilities ($0.4 million after-tax or $0.1 per diluted share) and $0.2 million of charges related to TimBar Corporation and Columbus Container integration costs ($0.1 million after-tax or $0.0 per diluted share). Also includes $5.0 million of costs for the property damage and business interruption insurance deductible corresponding to the February 2017 explosion at our DeRidder, Louisiana mill ($3.1 million after-tax or $0.03 per diluted share) and $2.3 million of income related to a working capital adjustment from the April 2015 sale of our Hexacomb corrugated manufacturing operations in Europe and Mexico ($1.4 million after-tax or $0.01 per diluted share).
[5]	Includes $4.5 million of charges related to the closure of a corrugated products facility and a paper products facility ($2.9 million after-tax or $0.03 per diluted share), $2.7 million of costs related to ceased production of softwood market pulp operations at our Wallula, Washington mill and the permanent shutdown of the No. 1 machine ($1.8 million after-tax or $0.02 per diluted share), and $1.2 million of charges related to the TimBar Corporation and Columbus Container acquisitions and integration ($0.8 million after-tax or $0.01 per diluted share).
[6]	Includes $2.0 million of charges related to the closure of a corrugated products facility and a paper products facility ($1.4 million after-tax or $0.02 per diluted share) and $2.9 million of charges related to the TimBar Corporation and Columbus Container acquisitions and integration ($1.9 million after-tax or $0.02 per diluted share).
[7]	Includes $2.6 million of charges related to the closure of corrugated products facilities, a paper products facility, and a lump sum settlement of a multiemployer pension plan withdrawal liability for one of our corrugated products facilities ($1.6 million after-tax or $0.02 per diluted share) and $0.3 million of charges related to the TimBar Corporation acquisition and integration ($0.2 million after-tax or $0.0 per diluted share).
[8]	Includes $2.8 million of charges related to the closure of a corrugated products facility and a paper products facility ($1.9 million after-tax or $0.02 per diluted share).
[9]	Includes income related to a working capital adjustment from the April 2015 sale of our Hexacomb corrugated manufacturing operations in Europe and Mexico.
[10]	Includes $1.8 million of expense related to the write-off of deferred debt issuance costs in connection with the December 2017 debt refinancing.
[11]	Includes a gain related to the expiration of a repurchase option corresponding to timberland previously sold.
[12]	(a)Includes the following: $7.2 million of income, net, primarily related to the sale of land corresponding to the closure of a corrugated products facility, partially offset by closure costs related to corrugated products facilities, and a lump sum settlement of a multiemployer pension plan withdrawal liability for one of our corrugated products facilities. $1.7 million of charges related to the Sacramento Container acquisition and integration costs related to other recent acquisitions. $2.0 million gain related to the expiration of a repurchase option corresponding to timberland previously sold. $1.6 million of income related to a working capital adjustment from the April 2015 sale of our Hexacomb corrugated manufacturing operations in Europe and Mexico. $5.0 million of costs for the property damage and business interruption insurance deductible corresponding to the February 2017 explosion at our DeRidder, Louisiana mill.
[13]	Includes $10.2 million of closure costs related to corrugated product facilities and a lump sum settlement of a multiemployer pension plan withdrawal liability for one of our corrugated products facilities and $4.2 million of acquisition-related costs for the TimBar Corporation and Columbus Container acquisitions.
[14]	Includes net charges of $2.0 million primarily related to restructuring activities at our mill in DeRidder, Louisiana and $4.1 million of Boise acquisition integration-related and other costs.