PotlatchDeltic (PCH) 10-K 16 Feb 18 2017 FY Annual report Financial data

Document And Entity Information

Document And Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Jan. 31, 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	PCH
Entity Registrant Name	POTLATCH CORP
Entity Central Index Key	1,338,749
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		40,611,991
Entity Public Float			$ 1,855.9

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Statement [Abstract]
Revenues	$ 678,595	$ 599,099	$ 575,336
Costs and expenses:
Cost of goods sold	470,365	462,304	470,037
Selling, general and administrative expenses	55,408	51,697	46,392
Environmental charges for Avery Landing	4,978	1,022
Deltic merger-related costs	3,409
Gain on lumber price swap	(1,088)
Loss on sale of central Idaho timber and timberlands		48,522
Total costs and expenses	533,072	563,545	516,429
Operating income	145,523	35,554	58,907
Interest expense, net	(27,049)	(28,941)	(32,761)
Income before income taxes	118,474	6,613	26,146
Income tax (provision) benefit	(32,021)	4,325	5,568
Net income	$ 86,453	$ 10,938	$ 31,714
Net income per share:
Basic (in dollars per share)	$ 2.12	$ 0.27	$ 0.78
Diluted (in dollars per share)	2.10	0.27	0.77
Dividends per share (in dollars per share)	$ 1.525	$ 1.50	$ 1.50
Weighted-average shares outstanding (in thousands)
Basic (in shares)	40,824,420	40,797,806	40,842,126
Diluted (in shares)	41,227,388	41,033,440	40,987,819

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 86,453	$ 10,938	$ 31,714
Other comprehensive income, net of tax:
Net gain (loss) arising during the period, net of tax expense (benefit) of $3,990, $(1,826) and $(1,913)	11,355	(2,857)	(2,990)
Amortization of actuarial loss included in net periodic cost, net of tax expense of $6,248, $7,042 and $7,794	9,773	11,014	12,190
Amortization of prior service credit included in net periodic cost, net of tax benefit of $(3,350), $(3,260) and $(3,396)	(5,239)	(5,099)	(5,311)
Cash flow hedge, net of tax of $3, $448, and $-	4	701	0
Other comprehensive income, net of tax	15,893	3,759	3,889
Comprehensive income	$ 102,346	$ 14,697	$ 35,603

Consolidated Statements of Com4

Consolidated Statements of Comprehensive Income (Parentheticals) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement Of Income And Comprehensive Income [Abstract]
Net gain (loss) arising during the period, tax expense (benefit)	$ 3,990	$ (1,826)	$ (1,913)
Amortization of actuarial loss included in net periodic cost, tax expense	6,248	7,042	7,794
Amortization of prior service credit included in net periodic cost, tax benefit	(3,350)	(3,260)	(3,396)
Cash flow hedge, tax effect	$ 3	$ 448	$ 0

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 120,457	$ 82,584
Customer receivables, net of allowance for doubtful accounts of $260 and $510	11,240	14,842
Inventories	50,132	52,622
Other current assets	11,478	13,597
Total current assets	193,307	163,645
Property, plant and equipment, net	77,229	72,820
Timber and timberlands, net	654,476	641,856
Deferred tax assets, net	19,796	42,051
Other long-term assets	8,271	7,309
Total assets	953,079	927,681
Current liabilities:
Current portion of long-term debt	14,263	11,032
Accounts payable and accrued liabilities	55,201	43,710
Current portion of pension and other postretirement employee benefits	5,334	5,839
Total current liabilities	74,798	60,581
Long-term debt	559,056	572,956
Pension and other postretirement employee benefits	103,524	123,284
Other long-term obligations	15,159	14,586
Total liabilities	752,537	771,407
Commitments and contingencies
Stockholders’ equity:
Preferred stock, authorized 4,000,000 shares, no shares issued	0	0
Common stock, $1 par value, authorized 100,000,000 shares, issued 40,611,991 and 40,519,351 shares	40,612	40,519
Additional paid-in capital	359,144	355,274
Accumulated deficit	(104,363)	(128,775)
Accumulated other comprehensive loss	(94,851)	(110,744)
Total stockholders’ equity	200,542	156,274
Total liabilities and stockholders' equity	$ 953,079	$ 927,681

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Statement Of Financial Position [Abstract]
Allowance for doubtful accounts	$ 260	$ 510
Preferred stock, authorized	4,000,000	4,000,000
Preferred stock, issued	0	0
Common stock, par value	$ 1	$ 1
Common stock, authorized	100,000,000	100,000,000
Common stock, issued	40,611,991	40,519,351

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 86,453	$ 10,938	$ 31,714
Adjustments to reconcile net income to net cash from operating activities:
Depreciation, depletion and amortization	29,912	34,190	38,105
Basis of real estate sold	6,827	8,011	7,012
Change in deferred taxes	15,364	1,853	(5,696)
Pension and other postretirement employee benefits	13,151	15,661	15,122
Equity-based compensation expense	4,722	4,390	4,758
Loss on sale of central Idaho timber and timberlands		48,522
Other, net	(1,872)	(1,198)	(2,046)
Change in:
Receivables	3,602	(3,712)	(3,864)
Inventories	2,490	(17,460)	(3,672)
Other assets	(15)	(473)	898
Accounts payable and accrued liabilities	11,591	7,232	267
Other liabilities	(4,291)	(4,537)	(8,584)
Funding of qualified pension plans	(5,275)	(1,300)
Net cash from operating activities	162,659	102,117	74,014
CASH FLOWS FROM INVESTING ACTIVITIES
Change in short-term investments			6,995
Transfer from company owned life insurance (COLI)	1,278	6,384	1,492
Transfer to COLI	(1,324)	(3,967)
Purchase of property, plant and equipment	(12,855)	(5,866)	(18,987)
Timberlands reforestation and roads	(15,207)	(13,422)	(13,745)
Acquisition of timber and timberlands	(22,043)	(1,244)	(10,230)
Net proceeds from sale of central Idaho timber and timberlands		111,460
Other, net	131	6	886
Net cash from investing activities	(50,020)	93,351	(33,589)
CASH FLOWS FROM FINANCING ACTIVITIES
Dividends to common stockholders	(61,931)	(60,842)	(61,017)
Repurchase of common stock		(5,956)
Revolving line of credit (repayment) borrowings		(30,000)	30,000
Repayment of long-term debt	(11,000)	(113,335)	(22,500)
Proceeds from issuance of long-term debt		93,235
Other, net	(1,835)	(3,911)	(3,000)
Net cash from financing activities	(74,766)	(120,809)	(56,517)
Change in cash and cash equivalents	37,873	74,659	(16,092)
Cash and cash equivalents at beginning of year	82,584	7,925	24,017
Cash and cash equivalents at end of year	120,457	82,584	7,925
Cash paid (received) during the year for:
Interest, net of amounts capitalized	26,125	28,051	29,676
Income taxes, net	$ 15,845	$ (8,081)	$ 1,576

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Loss [Member]
Balance, beginning of period at Dec. 31, 2014	$ 225,066	$ 40,605	$ 346,441	$ (43,588)	$ (118,392)
Balance, beginning of period (shares) at Dec. 31, 2014		40,605,179
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Performance shares and restricted stock units	3,390	$ 76	3,406	(92)
Performance share and restricted stock unit (shares)		75,534
Net income	31,714			31,714
Director deferred stock awards	701		701
Pension plans and OPEB obligations	3,889				3,889
Transfer of assets from REIT to subsidiary	(7)		(7)
Cash flow hedge, net of tax of $3, $448, and $-	0
Common distributions, $1.50 per share 2015, $1.50 per share 2016, $1.525 per share 2017	(61,017)			(61,017)
Balance, end of period at Dec. 31, 2015	203,736	$ 40,681	350,541	(72,983)	(114,503)
Balance, end of period (shares) at Dec. 31, 2015		40,680,713
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Performance shares and restricted stock units	3,971	$ 8	4,065	(102)
Performance share and restricted stock unit (shares)		8,263
Net income	10,938			10,938
Director deferred stock awards	668		668
Pension plans and OPEB obligations	3,058				3,058
Repurchase of common stock	(5,956)	$ (170)		(5,786)
Repurchase of common stock (shares)		(169,625)
Cash flow hedge, net of tax of $3, $448, and $-	701				701
Common distributions, $1.50 per share 2015, $1.50 per share 2016, $1.525 per share 2017	(60,842)			(60,842)
Balance, end of period at Dec. 31, 2016	156,274	$ 40,519	355,274	(128,775)	(110,744)
Balance, end of period (shares) at Dec. 31, 2016		40,519,351
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Performance shares and restricted stock units	3,435	$ 93	3,452	(110)
Performance share and restricted stock unit (shares)		92,640
Net income	86,453			86,453
Director deferred stock awards	418		418
Pension plans and OPEB obligations	15,889				15,889
Repurchase of common stock (shares)		0
Cash flow hedge, net of tax of $3, $448, and $-	4				4
Common distributions, $1.50 per share 2015, $1.50 per share 2016, $1.525 per share 2017	(61,931)			(61,931)
Balance, end of period at Dec. 31, 2017	$ 200,542	$ 40,612	$ 359,144	$ (104,363)	$ (94,851)
Balance, end of period (shares) at Dec. 31, 2017		40,611,991

Consolidated Statements of Sto9

Consolidated Statements of Stockholders' Equity (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement Of Stockholders Equity [Abstract]
Common dividends, per share	$ 1.525	$ 1.50	$ 1.50

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	NOTE 1. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES GENERAL We are primarily engaged in activities associated with timberland management, including the sale of timber, the management of approximately 1.4 million acres of timberlands and the purchase and sale of timberlands. We are also engaged in the manufacture and sale of wood products. Our timberlands and all of our wood products facilities are located within the continental United States. The primary market for our products is the United States. We converted to a Real Estate Investment Trust (REIT) effective January 1, 2006. CONSOLIDATION The Consolidated Financial Statements SIGNIFICANT ESTIMATES The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America, which we refer to in this report as U.S. GAAP, requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates and assumptions. Significant estimates include timber volumes, pension and postretirement obligation assumptions, contingent liabilities and the fair value of derivative instruments. These significant estimates are described in further detail below. Cash and Cash Equivalents Cash equivalents are investments that are highly liquid with maturities of three months or less when purchased. INVENTORIES For most of our operations, the last-in, first-out method is used to determine the cost of logs, lumber and plywood. The average cost method is used to determine the cost of all other inventories. Inventories are stated at the lower of cost or net realizable value. Expenses associated with idle capacity or other curtailments of production are reflected in cost of goods sold in the periods incurred. PROPERTY, PLANT AND EQUIPMENT Property, plant and equipment are valued at cost less accumulated depreciation. Depreciation of buildings, equipment and other depreciable assets is determined using the straight-line method of depreciation. Major improvements and replacements of property are capitalized. Maintenance, repairs and minor improvements and replacements are expensed. Upon retirement or other disposition of property, applicable cost and accumulated depreciation are removed from the accounts. Any gains or losses are included in earnings. TIMBER AND TIMBERLANDS Timber and timberlands are valued at cost less accumulated depletion and amortization. We capitalize costs related to stand establishment, which include the preparation of the land for planting, seeds or seedlings and tree planting costs, which include third-party labor costs, materials and other contract services. Upon completion of planting activities and field inspection to confirm the planting operation was successful, a plantation will be considered “established.” Subsequent expenditures to maintain the integrity or enhance the growth of an established plantation or stand are expensed. Post-establishment expenses include vegetation control, fertilization, thinning operations and the replanting of seedlings lost through mortality. Forest management costs are considered current operating expenses and include property taxes and insurance, silviculture costs incurred subsequent to stand establishment, cruising (physical inventory), property maintenance, salaries, supplies, travel, record-keeping, fire protection and other normal recurring administrative personnel costs. Timberland acquisitions are capitalized based on the relative appraised values of timberland, merchantable sawlogs, merchantable pulpwood, pre-production timber (young growth that is not yet merchantable timber), logging roads and other land improvements. The estimated volume of current standing merchantable timber inventory, which is a component of calculating our depletion rates, is updated at least annually to reflect increases due to the reclassification of pre-production timber to merchantable timber when it meets defined diameter specifications, the annual growth of merchantable timber and the acquisition of additional merchantable timber, decreases due to timber harvests and land sales and changes resulting from other factors, such as environmental or casualty losses. Timber volumes are estimated from cruises of the timber tracts, which are completed on our timberlands on approximately a five to ten year cycle. Depletion represents the amount charged to expense as timber is harvested. Rates at which timber is depleted are calculated annually for each of our depletion pools by dividing the beginning of year balance of the merchantable timber accounts by the forest inventory volume, after inventory updates. The base cost of logging roads, such as clearing, grading and ditching, is not amortized and remains a capitalized item until disposition. Other portions of the initial logging road cost, such as bridges, culverts and gravel surfacing are amortized over their useful lives, which range from 5 to 20 years. Costs associated with temporary logging road spurs, which are typically used for one harvest season, are expensed as incurred. REAL ESTATE SALES Sales of non-core timberland are considered to be part of our normal operations. We therefore classify revenue and costs associated with real estate sold in revenues and cost of goods sold, respectively, in our Consolidated Statements of Income Consolidated Statements of Cash Flows . Sales of large parcels of property, such as our sale of central Idaho timberlands in 2016, which do not represent our core operations and are of such a size as to not be indicative of our ongoing operations, are presented as a net gain or loss in our Consolidated Statements of Income Consolidated Statements of Cash Flows . LONG-LIVED ASSETS Our long-lived assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable, as measured by its undiscounted estimated future cash flows. We use our operational budgets to estimate future cash flows. The estimates are adjusted periodically to reflect changing business conditions. Impaired assets are written down to fair value. Assets to be disposed of are reported at the lower of carrying amount or fair value less cost to sell. We recognize a liability and an asset equal to the fair value of our legal obligations to perform asset retirement activities if the amount can be reasonably estimated. We review these obligations annually and do not expect them to have a material effect on our financial position, results of operations or cash flows. INCOME TAXES We use the asset and liability method of accounting for income taxes. Under this method, deferred tax assets and liabilities are recognized for the estimated future tax consequences attributable to differences between the financial statement carrying amounts of assets and liabilities and their respective tax bases, operating loss carryforwards and tax credit carryforwards. Deferred tax assets and liabilities are measured pursuant to tax laws using rates expected to apply to taxable income in the years in which the temporary differences are expected to be recovered or settled. We recognize the effect of a change in income tax rates on deferred tax assets and liabilities in the Consolidated Statements of Income Consolidated Statements of Comprehensive Income REVENUE RECOGNITION We recognize revenue from the sale of timber when risk of loss transfers to the buyer and the quantity sold is determinable. These sales usually take the form of delivered logs, pay-as-cut stumpage contracts, lump sum stumpage contracts or timber deeds. On delivered log sales, revenue includes amounts billed for logging and hauling and is recognized at the point the logs are delivered and scaled. Revenue is recognized on timber deeds and lump sum stumpage contracts generally upon closing or when the contracts are effective, which is the point at which the buyer assumes risk of loss associated with the standing timber. We recognize revenue from the sale of manufactured wood products and residual by-products when there is persuasive evidence of a sales agreement, the price to the customer is fixed and determinable, collection is reasonably assured and title and the risk of loss passes to the customer. Shipping terms generally indicate when title and the risk of loss have passed. Revenue is recognized at shipment when shipping terms are FOB (free on board) shipping point. For sales where shipping terms are FOB destination, revenue is recognized when the goods are received by the customer. We receive cash consideration in full and recognize revenue at closing on substantially all of our real estate sales. While sales taxes are not typical, in the event sales taxes are collected, revenue is recognized net of any sales tax and sales taxes are recorded as a current liability and remitted to the appropriate governmental entities. Costs for shipping and handling are included in cost of goods sold in our Consolidated Statements of Income EQUITY-BASED COMPENSATION Equity-based awards are measured at fair value on the dates they are granted or modified. These measurements establish the cost of the equity-based awards for accounting purposes. The cost of the equity-based award is then recognized in the Consolidated Statements of Income Note 14: Equity-Based Compensation Plans NEW ACCOUNTING PRONOUNCEMENTS In March 2016, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2016-09, Improvements to Employee Share-Based Payment Accounting In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers: Topic 606 Revenue from Contracts with Customers (Topic 606), Deferral of the Effective Date In March 2017, the FASB issued ASU No. 2017-07, Compensation – Retirement Benefits (Topic 715), Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost In October 2016, the FASB issued ASU No. 2016-16, Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other Than Inventory In January 2017, the FASB issued ASU 2017-1, Business Combinations (Topic 805): Clarifying the Definition of a Business In August 2017, the FASB issued ASU No. 2017-12, Derivatives and Hedging (Topic 815), Targeted Improvements to Accounting for Hedging Activities In February 2016, the FASB issued ASU No. 2016-02, Leases In February 2018, the FASB issued ASU No. 2018-2, Income Statement – Reporting Comprehensive Income (Topic 220), Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income Note 15: Income Taxes RECLASSIFICATIONS Prior year environmental charges for Avery Landing within the Consolidated Statements of Income Prior year receivables not due from customers within the Consolidated Balance Sheets Note 7: Other Current Assets Certain 2016 and 2015 amounts within cash flows from operations on the Consolidated Statements of Cash Flows

Pending Merger With Deltic

Pending Merger With Deltic	12 Months Ended
	Dec. 31, 2017
Business Combinations [Abstract]
Pending Merger With Deltic	NOTE 2. Pending Merger with Deltic On October 22, 2017, Potlatch, Portland Merger, LLC (Merger Sub), a wholly-owned subsidiary of Potlatch, and Deltic Timber Corporation (Deltic) entered into an Agreement and Plan of Merger (Merger Agreement) pursuant to which Deltic will merge with and into Merger Sub. Following the merger, Potlatch will be renamed PotlatchDeltic Corporation. Under the terms of the Merger Agreement, Deltic shareholders will receive 1.80 shares of Potlatch common stock for each share of Deltic common stock at the closing date. Deltic owns approximately 530,000 acres of timberland, operates two sawmills and a medium density fiberboard plant and is engaged in real estate development primarily in Arkansas. Because the exchange ratio was fixed at the time of the Merger Agreement and the market value of our common stock will continue to fluctuate, the total value of the consideration exchanged will not be determinable until the closing date. The number of shares to be issued with respect to Deltic stock awards will not be determinable until the closing of the transaction. We estimated that approximately 22 million shares of our common stock will be issued to Deltic shareholders in the merger based on the 1.80 exchange ratio and the number of shares of Deltic common stock issued and outstanding as of January 31, 2018. The Merger Agreement provides that, upon termination of the Merger Agreement by a party under certain circumstances, such party may be obligated to pay the other party a termination fee equal to $66 million with respect to the fee payable by Potlatch and $33 million with respect to the fee payable by Deltic. Subsequent to the completion of the transaction, as part of the REIT conversion process, Deltic’s earnings and profits are expected to be distributed to shareholders of the combined company through a dividend or special distribution consisting of 80% stock and 20% cash. The closing of the merger is subject to approval by the shareholders of Deltic and Potlatch and other conditions specified in the Merger Agreement. The respective shareholder meetings are scheduled for February 20, 2018, as published in the joint proxy statement/prospectus dated January 18, 2018. If approved by the shareholders, the merger is expected to close the same day .

Earnings per Share

Earnings per Share	12 Months Ended
	Dec. 31, 2017
Earnings Per Share Basic Other Disclosures [Abstract]
Earnings per Share	NOTE 3. EARNINGS PER SHARE The following table reconciles the number of shares used in calculating the basic and diluted earnings per share for the years ended December 31: (Dollars in thousands, except per share amounts) 2017 2016 2015 Net income $ 86,453 $ 10,938 $ 31,714 Basic weighted-average shares outstanding 40,824,420 40,797,806 40,842,126 Incremental shares due to: Performance shares 362,509 200,164 122,334 Restricted stock units 40,459 35,470 23,359 Diluted weighted-average shares outstanding 41,227,388 41,033,440 40,987,819 Basic net income per share $ 2.12 $ 0.27 $ 0.78 Diluted net income per share $ 2.10 $ 0.27 $ 0.77 For stock-based awards, the dilutive effect is calculated using the treasury stock method. Under this method, the dilutive effect is computed as if the awards were exercised at the beginning of the period (or at time of issuance, if later) and assumes the related proceeds were used to repurchase common stock at the average market price during the period. Related proceeds include future compensation cost associated with the stock award. At December 31, 2017 and 2016, there were 250 and 503 stock-based awards, respectively, which were excluded from the calculation of earnings per share because they were anti-dilutive. At December 31, 2015, there were no anti-dilutive stock-based awards. On April 26, 2016, we announced that our board of directors had authorized management to repurchase up to $60 million of common stock over a period of 24 months (the “Repurchase Plan”). We repurchased 169,625 shares of common stock during the second quarter of 2016 at an average price of $35.08 per share. We retire shares upon repurchase. Any excess repurchase price over par is recorded in accumulated deficit. No shares were repurchased during 2017 and $54 million remains available on the authorization.

Inventories

Inventories	12 Months Ended
	Dec. 31, 2017
Inventory Disclosure [Abstract]
Inventories	NOTE 4. INVENTORIES (Dollars in thousands) 2017 2016 Logs $ 20,133 $ 23,342 Lumber, plywood and veneer 20,889 20,500 Materials and supplies 9,110 8,780 $ 50,132 $ 52,622 Valued at lower of cost or net realizable value: Last-in, first-out basis $ 25,127 $ 29,769 Average cost basis 25,005 22,853 Total inventories $ 50,132 $ 52,622 If the last-in, first-out inventory had been carried at average cost, the values would have been higher by approximately $10.9 million, $11.1 million and $10.6 million at December 31, 2017, 2016 and 2015, respectively.

Property, Plant and Equipment

Property, Plant and Equipment	12 Months Ended
	Dec. 31, 2017
Property Plant And Equipment [Abstract]
Property, Plant and Equipment	NOTE 5. PROPERTY, PLANT AND EQUIPMENT (Dollars in thousands) Range of useful lives 2017 2016 Land $ 4,707 $ 4,712 Buildings and improvements 10-40 years 55,734 54,448 Machinery and equipment 2-25 years 197,648 190,316 Construction in progress 1,348 1,437 259,437 250,913 Less: accumulated depreciation (182,208 ) (178,093 ) Total property, plant and equipment, net $ 77,229 $ 72,820 Depreciation charged against operating income totaled $8.1 million, $8.3 million and $8.2 million in 2017, 2016 and 2015, respectively. Interest expense capitalized was inconsequential in 2017 and 2016, and $0.2 million 2015.

Timber and Timberlands

Timber and Timberlands	12 Months Ended
	Dec. 31, 2017
Timber And Timberlands [Abstract]
Timber and Timberlands	NOTE 6. TIMBER AND TIMBERLANDS (Dollars in thousands) 2017 2016 Timber and timberlands $ 581,648 $ 572,273 Logging roads 72,828 69,583 Total timber and timberlands, net $ 654,476 $ 641,856 Depletion from company-owned lands totaled $17.0 million, $20.8 million and $25.3 million in 2017, 2016 and 2015, respectively. Amortization of road costs, such as bridges, culverts and gravel surfacing, totaled $3.2 million, $3.1 million and $3.1 million in 2017, 2016 and 2015, respectively. Future payments due under timber cutting contracts as of December 31, 2017 are as follows: (Dollars in thousands) 2018 $ 11,280 2019 2,730 2020 1,085 2021 5,370 2022 281 Total $ 20,746

Other Current Assets

Other Current Assets	12 Months Ended
	Dec. 31, 2017
Other Assets [Abstract]
Other Current Assets	NOTE 7. OTHER CURRENT ASSETS (Dollars in thousands) 2017 2016 Real estate held for sale $ 7,721 $ 9,184 Prepaid expenses 2,862 1,939 Other receivables 882 2,442 Interest rate swaps 13 32 Total other current assets $ 11,478 $ 13,597

Accounts Payable and Accrued Li

Accounts Payable and Accrued Liabilities	12 Months Ended
	Dec. 31, 2017
Accounts Payable And Accrued Liabilities Current And Noncurrent [Abstract]
Accounts Payable and Accrued Liabilities	NOTE 8. ACCOUNTS PAYABLE AND ACCRUED LIABILITIES (Dollars in thousands) 2017 2016 Accrued payroll and benefits $ 18,110 $ 13,634 Accounts payable 9,361 8,382 Accrued interest 6,385 6,237 Avery Landing accrual 6,000 1,022 Accrued taxes 5,103 4,956 Other current liabilities 10,242 9,479 Total accounts payable and accrued liabilities $ 55,201 $ 43,710

Debt

Debt	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Debt	NOTE 9. DEBT (Dollars in thousands) 2017 2016 Term loans $ 343,500 $ 349,500 Senior notes 150,000 150,000 Revenue bonds 65,735 65,735 Medium-term notes 17,250 22,250 Long-term principal 576,485 587,485 Interest rate swaps (373 ) 247 Debt issuance costs (2,321 ) (3,015 ) Unamortized discounts (472 ) (729 ) Total long-term debt (includes current portion) 573,319 583,988 Less current portion of long-term debt (14,263 ) (11,032 ) Long-term debt $ 559,056 $ 572,956 TERM LOANS We repaid $6 million of our term loans in 2017. The remaining term loans include eight tranches consisting of the following: • one • three $40 million tranches maturing each year from 2019 through 2021 at variable rates based on three-month LIBOR plus a spread between 1.65% and 1.90% (term loan variable rates are based on three-month LIBOR of 1.34%, which is the rate incurred during the fourth quarter of 2017); • two $40 million tranches with rates of 4.29% maturing in 2022 and 4.49% maturing in 2023; • one tranche of $110 million with a rate of 4.64% maturing in 2024; and • one tranche of $27.5 million with a rate of 2.15% plus three-month LIBOR maturing in 2026. SENIOR NOTES In 2009, we sold $150 million aggregate principal amount of 7.50% senior notes due in 2019. The terms of these notes limit our ability, and the ability of any subsidiary guarantors, to borrow money, pay dividends, redeem or repurchase capital stock, enter into sale and leaseback transactions and create liens. MEDIUM-TERM NOTES AND REVENUE BONDS The medium-term notes were originally issued during 1991 and 1992 with fixed rates of 8.75% to 8.89% due 2018 through 2022. Repayment of $5 million of our medium-term notes occurred in 2017. In 2016, we repaid $42.6 million of revenue bonds. The bonds carried a rate of 5.90% and matured in 2026. In 2016, we also refinanced $65.7 million of revenue bonds at a rate of 2.75%. The original bonds, which carried a rate of 6.00%, were extinguished and a new debt obligation was simultaneously issued. The principal balance and maturity date in 2024 remain unchanged. DEBT ISSUANCE COSTS Debt issuance costs represent the capitalized direct costs incurred related to the issuance of debt. These costs are amortized to interest expense over the terms of the respective borrowings. DEBT MATURITIES Scheduled principal payments due on long-term debt as of December 31, 2017 are as follows: (Dollars in thousands) 2018 $ 14,250 2019 190,000 2020 46,000 2021 40,000 2022 43,000 Thereafter 243,235 Total $ 576,485 Principal repayments on long-term debt occur at maturity. Our debt obligations are of equal priority. CREDIT AGREEMENT In 2014, we entered into an amended and restated credit agreement with an expiration date of February 12, 2020. The credit agreement provides for a revolving line of credit with an initial aggregate principal amount not to exceed $250 million, which may be increased by up to an additional $250 million. It also includes a sublimit of $40 million for the issuance of standby letters of credit and a sublimit of $25 million for swing line loans. Usage under either or both subfacilities reduces availability under the revolving line of credit. As of December 31, 2017, there were no Pricing is set according to the type of borrowing. LIBOR Loans are issued at a rate equal to the British Bankers Association LIBOR Rate, while Base Rate Loans are issued at a rate equal to the Base Rate, which is a fluctuating rate per annum equal to the highest of (a) the Federal Funds Rate plus 1/2 of 1.00%, (b) the rate of interest in effect for such day as publicly announced from time to time by KeyBank as its “prime rate” and (c) the sum of the LIBOR that would apply to a one month Interest Period plus 1.00%. The interest rates we pay for borrowings under either type of loan include an additional Applicable Rate, which can range from 0.875% to 1.70% for LIBOR loans and from 0% to 0.70% for Base Rate loans, depending on our current credit rating. As of December 31, 2017, we were able to borrow under the bank credit facility with the additional applicable rate of 1.50% for LIBOR Loans and 0.50% for Base Rate Loans, with facility fees of 0.25% on the $250 million of the bank credit facility. On February 14, 2018, we entered into a second amended and restated credit agreement (the Amended Credit Agreement) with an expiration date of April 14, 2023. The Amended Credit Agreement increases our revolving line of credit to $380 million, which may be increased by up to an additional $420 million It also includes a sublimit of $75 million for the issuance of standby letters of credit and a sublimit of $25 million for swing line loans. Usage under either or both subfacilities reduces availability under the revolving line of credit. Pricing is consistent with the 2014 amended and restated credit agreement. The interest coverage ratio and leverage ratio financial covenants are unchanged. The limitation on timberland acre sales was eliminated.

Derivative Instruments

Derivative Instruments	12 Months Ended
	Dec. 31, 2017
Derivative Instrument Detail [Abstract]
Derivative Instruments	NOTE 10. DERIVATIVE INSTRUMENTS From time to time, we enter into derivative financial instruments to manage certain cash flow and fair value risks. Derivatives designated and qualifying as a hedge of the exposure to changes in the fair value of an asset or liability to a particular risk, such as interest rate risk, are considered fair value hedges. We have three fair value interest rate swaps with notional amounts totaling $14.3 million associated with our medium-term notes. The fair value swaps convert interest payments with fixed rates ranging between 8.88% and 8.89% to a variable rate of 3-month LIBOR plus a spread of 6.17%. Our fair value swaps terminate at various dates in the first quarter of 2018. A $50 million notional fair value swap associated with our senior notes was terminated in December 2017 at a cost of $0.4 million. The termination cost has been recorded as a reduction to the carrying value of our long-term debt and will be amortized to earnings through the original maturity date of November 2019. Approximately $0.2 million will be recorded as interest expense over the next twelve months. Derivatives designated and qualifying as a hedge of the exposure to variability in the cash flows of a specific asset or liability that is attributable to a particular risk, such as interest rate risk, are considered cash flow hedges. We have one interest rate swap with a notional amount of $27.5 million associated with $27.5 million of term loan debt. The cash flow hedge converts a variable rate of 2.15% plus 3-month LIBOR to a fixed rate of 3.88% and terminates in February 2026. Our cash flow hedge is expected to be highly effective in achieving offsetting cash flows attributable to the hedged interest rate risk through the term of the hedge. Therefore, changes in the fair value of the interest rate swap are recorded as a component of other comprehensive income and will be recognized in earnings when the hedged interest rate affects earnings. Changes in the fair value of the ineffective portion are recognized immediately in earnings. There has been no impact on earnings due to ineffectiveness to date. As of December 31, 2017, the amount of net losses expected to be reclassified into earnings in the next 12 months is inconsequential. Derivatives not designated as hedges are not speculative and are used to manage our exposure to interest rate movements, commodity price movements or other identified risks, but do not meet the strict hedge accounting requirements. Changes in the fair value of derivatives not designated in hedging relationships are recorded directly into income. In April 2017, we entered into a lumber price swap to fix the price on a total of 36 million board feet (MMBF) of southern yellow pine. The lumber price swap expired on December 31, 2017, resulting in a realized gain of $1.1 million for the period then ended. The fair values of our cash flow and fair value derivative instruments on our Consolidated Balance Sheets Asset Derivatives Liability Derivatives (Dollars in thousands) Location 2017 2016 Location 2017 2016 Derivatives designated in fair value hedging relationships: Interest rate contracts Other assets, current $ 13 $ 32 $ — $ — Interest rate contracts Other assets, non-current 215 Other long-term obligations 91 $ 13 $ 247 $ — $ 91 Derivatives designated in cash flow hedging relationships: Interest rate contracts Other assets, non-current $ 1,156 $ 1,148 $ — $ — The following table details the effect of derivatives on our Consolidated Statements of Income (Dollars in thousands) Location 2017 2016 2015 Derivatives designated in fair value hedging relationships: Interest rate contracts Realized gain on interest rate contracts 1 Interest expense $ 413 $ 805 $ 1,534 Derivatives designated in cash flow hedging relationships: Interest rate contracts Gain (loss) recognized in other comprehensive income, net of tax (effective portion) $ (145 ) $ 916 $ — Loss reclassified from accumulated other comprehensive income (effective portion) 1 Interest expense $ (149 ) $ (215 ) $ — Derivatives not designated as hedging instruments: Lumber price contracts Realized gain on lumber price swap Gain on lumber price swap $ 1,088 $ — $ — 1 Realized gains and losses on interest rate contracts consist of net cash received or paid and interest accruals on the interest rate swaps during the periods. Net cash received or paid is included in the supplemental cash flow information within interest, net of amounts capitalized in the Consolidated Statements of Cash Flows .

Financial Instruments

Financial Instruments	12 Months Ended
	Dec. 31, 2017
Derivative Instrument Detail [Abstract]
Financial Instruments	NOTE 11. FINANCIAL INSTRUMENTS FAIR VALUE OF FINANCIAL INSTRUMENTS Estimated fair values of our financial instruments as of December 31 are as follows: 2017 2016 (Dollars in thousands) Carrying Amount Fair Value Carrying Amount Fair Value Cash and cash equivalents (Level 1) $ 120,457 $ 120,457 $ 82,584 $ 82,584 Derivative assets related to interest rate swaps (Level 2) $ 1,169 $ 1,169 $ 1,395 $ 1,395 Derivative liabilities related to interest rate swaps (Level 2) $ — $ — $ (91 ) $ (91 ) Long-term debt, including current portion (Level 2): Term loans $ (343,500 ) $ (345,222 ) $ (349,500 ) $ (350,909 ) Senior notes (149,528 ) (161,063 ) (149,271 ) (164,250 ) Revenue bonds (65,735 ) (63,967 ) (65,735 ) (62,205 ) Medium-term notes (17,250 ) (18,227 ) (22,250 ) (23,926 ) Total long-term debt 1 $ (576,013 ) $ (588,479 ) $ (586,756 ) $ (601,290 ) Company owned life insurance (COLI) (Level 3) $ 1,996 $ 1,996 $ 70 $ 70 1 The carrying amount of long-term debt includes principal and unamortized discounts A framework has been established for measuring fair value, which provides a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value. The three levels of the fair value hierarchy are described below. Level 1 Level 2 • quoted prices for similar assets or liabilities in active markets; • quoted prices for identical or similar assets or liabilities in inactive markets; • inputs other than quoted prices that are observable for the asset or liability; and • inputs that are derived principally from or corroborated by observable market data by correlation or other means. Level 3 inputs to the valuation methodology are unobservable and significant to the fair value measurement. If the asset or liability has a specified (contractual) term, the Level 2 input must correspond to substantially the full term of the asset or liability. The fair value measurement level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. Valuation techniques used need to maximize the use of observable inputs and minimize the use of unobservable inputs. • For cash and cash-equivalents, the carrying amount approximates fair value due to the short-term nature of these financial instruments. • The fair value of the interest rate swaps was determined using discounted cash flow analysis on the expected cash flows of each derivative. The analysis reflects the contractual terms of the derivatives, including the period to maturity, and uses observable market-based inputs, including interest rate forward curves. • The fair value of our long-term debt is estimated based upon the quoted market prices for the same or similar debt issues, or estimated based on average market prices for comparable debt when there is no quoted market price. • The contract value of our COLI, the amount at which it could be redeemed, is used to estimate fair value because market prices are not readily available. COMPANY OWNED LIFE INSURANCE We are the beneficiary of insurance policies on the lives of certain current and past officers and employees. We have recognized the amount that could be realized upon surrender of the insurance policies in other assets in our Consolidated Balance Sheets Consolidated Statements of Income Consolidated Statements of Cash Flows .

Savings Plans, Pension Plans an

Savings Plans, Pension Plans and Other Postretirement Employee Benefits	12 Months Ended
	Dec. 31, 2017
General Discussion Of Pension And Other Postretirement Benefits [Abstract]
Savings Plans, Pension Plans and Other Postretirement Employee Benefits	NOTE 12. SAVINGS PLANS, PENSION PLANS AND OTHER POSTRETIREMENT EMPLOYEE BENEFITS SAVINGS PLANS Substantially all of our employees are eligible to participate in 401(k) savings plans. In 2017, 2016 and 2015, we made matching 401(k) contributions on behalf of our employees of $2.4 million, $2.1 million and $2.1 million, respectively. Certain eligible employees who earn awards under our annual incentive plan are permitted to defer receipt of those awards. These employees may defer receipt of a minimum of 50% and a maximum of 100% of the award pursuant to rules established under our Management Deferred Compensation Plan. Eligible employees may also defer up to 50% of their base salary under the Management Deferred Compensation Plan. At the employee's election, deferrals may be deemed invested in a company stock unit account, a directed investment account with certain deemed investments available under the 401(k) Plan or a combination of these investment vehicles. If company stock units are elected, dividend equivalents are credited to the units . PENSION PLANS AND OTHER POSTRETIREMENT BENEFITS On January 1, 2011, we froze our pension plans to any new salaried and hourly non-represented employees hired after that date. Effective January 1, 2010, we restructured our other postretirement benefit plans (OPEB). The level of health care subsidy was frozen for retirees so that all future increments in health care costs will be borne by the retirees. In addition, for retirees under age 65, a high deductible medical plan was created and all other existing health care plans were terminated. For retirees age 65 or over, the medical plan is divided into two components, with the company continuing to self-insure prescription drugs and providing a fully-insured medical supplemental plan through AARP/United Healthcare. Both health care plans require the retiree to contribute amounts in excess of the company subsidy in order to continue coverage. Finally, vision, dental and life insurance coverage for these retirees were terminated. The effect of these retiree plan changes was a reduction in the accumulated postretirement benefit obligation of $76.7 million, which was recognized in Accumulated Other Comprehensive Loss We use a December 31 measurement date for our benefit plans and obligations. We recognize the underfunded status of our defined benefit pension plans and OPEB obligations on our Consolidated Balance Sheets Consolidated Statements of Income The change in benefit obligation, change in plan assets and funded status for company-sponsored benefit plans and obligations are as follows: Pension Plans OPEB (Dollars in thousands) 2017 2016 2017 2016 Benefit obligation at beginning of year $ (385,461 ) $ (382,071 ) $ (33,337 ) $ (35,471 ) Service cost (6,753 ) (6,508 ) (14 ) (14 ) Interest cost (16,096 ) (17,020 ) (1,262 ) (1,421 ) Actuarial (loss) gain (15,876 ) (13,997 ) 471 (313 ) Benefits paid 31,815 34,135 3,793 3,882 Benefit obligation at end of year $ (392,371 ) $ (385,461 ) $ (30,349 ) $ (33,337 ) Fair value of plan assets at beginning of year $ 289,675 $ 292,200 $ — $ — Actual return on plan assets 49,158 28,626 — — Employer contributions and benefit payments 6,844 2,984 3,794 3,882 Benefits paid (31,815 ) (34,135 ) (3,794 ) (3,882 ) Fair value of plan assets at end of year $ 313,862 $ 289,675 $ — $ — Amounts recognized in the consolidated balance sheets: Current liabilities $ (1,629 ) $ (1,824 ) $ (3,705 ) $ (4,015 ) Noncurrent liabilities (76,880 ) (93,962 ) (26,644 ) (29,322 ) Funded status $ (78,509 ) $ (95,786 ) $ (30,349 ) $ (33,337 ) The accumulated benefit obligation for all defined benefit pension plans is determined using the actuarial present value of the vested benefits to which the employee is currently entitled and the employee’s expected date of separation for retirement and was $389.6 million and $379.5 million at December 31, 2017 and 2016, respectively. PENSION ASSETS We utilize formal investment policy guidelines for our company-sponsored pension plan assets. Management’s responsibility is that the investment policy and guidelines are adhered to and the investment objectives are met. The general policy states that plan assets will be invested to seek the greatest return consistent with the fiduciary character of the pension funds and to allow the plans to meet the need for timely pension benefit payments. The specific investment guidelines stipulate that management will maintain adequate liquidity for meeting expected benefit payments by reviewing, on a timely basis, contribution and benefit payment levels and appropriately revise long-term and short-term asset allocations. Management takes reasonable and prudent steps to preserve the value of pension fund assets and to avoid the risk of large losses. Major steps taken to provide this protection include the following: • Assets are diversified among various asset classes, such as domestic equities, global equities, fixed income, convertible securities and liquid reserves. The long-term asset allocation ranges are as follows: Domestic and international equities 24% - 48% Fixed income securities 38% - 58% Alternatives, which may include equities and fixed income securities 12% - 18% Cash and cash equivalents 0% - 5% • Periodic reviews of allocations within these ranges are made to determine what adjustments should be made based on changing economic and market conditions and specific liquidity requirements. • Assets are managed by professional investment managers and may be invested in separately managed accounts or commingled funds. Assets are diversified by selecting different investment managers for each asset class and by limiting assets under each manager to no more than 25% of the total pension fund. • Assets are not invested in Potlatch stock. The investment guidelines also provide that the individual investment managers are expected to achieve a reasonable rate of return over a market cycle. Emphasis will be placed on long-term performance versus short-term market aberrations. Factors to be considered in determining reasonable rates of return include performance achieved by a diverse cross section of other investment managers, performance of commonly used benchmarks (e.g., Russell 2500 Index, Barclays Long Credit Index, Morgan Stanley Capital International Index), actuarial assumptions for return on plan investments and specific performance guidelines given to individual investment managers. The asset allocations of the pension benefit plans’ assets at December 31 by asset category are as follows: Pension Plans Asset Category 2017 2016 Domestic and international equities 37 % 36 % Fixed income securities 47 48 Other (includes cash and cash equivalents and alternatives) 16 16 Total 100 % 100 % The pension assets are stated at fair value. Refer to Note 11: Financial Instruments Following is a description of the valuation methodologies used for assets measured at fair value: • Level 1 assets include cash and cash equivalents, corporate common and preferred stocks with quoted market prices on major securities markets, and investments in registered investment company funds for which market quotations are generally readily available on the primary market or exchange on which they are traded. • Level 2 assets consist primarily of collective investment trust funds, which are valued at their respective net asset value (NAV) and fully redeemable in the near-term. • Investments in funds that may not be fully redeemed in the near-term are generally classified in Level 3. We had no Level 3 investments at December 31, 2017 or 2016. Fair value measurements are as follows: (Dollars in thousands) December 31, 2017 Asset Category Level 1 Level 2 Total Cash and cash equivalents $ 3,004 $ — $ 3,004 Domestic equity securities 1 29,178 28,382 57,560 International equity securities 2 — 28,413 28,413 Emerging markets 3 12 29,245 29,257 Fixed income securities 4 148,833 — 148,833 Alternatives 5 — 46,795 46,795 Total $ 181,027 $ 132,835 $ 313,862 (Dollars in thousands) December 31, 2016 Asset Category Level 1 Level 2 Total Cash and cash equivalents $ 2,845 $ — $ 2,845 Domestic equity securities 1 25,409 26,279 51,688 International equity securities 2 — 26,555 26,555 Emerging markets 3 12 26,391 26,403 Fixed income securities 4 138,897 — 138,897 Alternatives 5 — 43,287 43,287 Total $ 167,163 $ 122,512 $ 289,675 1 Level 1 assets are managed investments in U.S. small/mid-cap equities that track the Russell 2500 Growth index or Russell 2500 Value index. Level 2 assets are collective investments, which are invested in U.S. large-cap equities that track the S&P 500. 2 3 Level 1 assets are mutual funds which are invested in the common stock of companies located (or with primary operations) in emerging markets that track the MSCI Emerging Markets index. Level 2 assets are collective investments in the common stock of companies located (or with primary operations) in emerging markets that track the MSCI Emerging Markets index. 4 5 Level 2 assets are collective investments in inflation-indexed bonds, securities of real estate companies, commodity index-linked notes, fixed income securities, foreign currencies, securities of natural resource companies, master limited partnerships, publicly listed infrastructure companies, floating-rate debt, securities of global agriculture companies and securities of global timber companies. PLAN ACTIVITY Pre-tax components of net periodic cost (benefit) recognized in our Consolidated Statements of Income Pension Plans OPEB (Dollars in thousands) 2017 2016 2015 2017 2016 2015 Service cost $ 6,753 $ 6,508 $ 6,159 $ 14 $ 14 $ 22 Interest cost 16,096 17,020 17,012 1,262 1,421 1,456 Expected return on plan assets (18,406 ) (18,999 ) (20,804 ) — — — Amortization of prior service cost (credit) 288 518 605 (8,877 ) (8,877 ) (9,312 ) Amortization of actuarial loss 14,484 16,339 17,937 1,537 1,717 2,047 Net periodic cost (benefit) $ 19,215 $ 21,386 $ 20,909 $ (6,064 ) $ (5,725 ) $ (5,787 ) Other amounts recognized in our Consolidated Statements of Comprehensive Income Pension Plans OPEB (Dollars in thousands) 2017 2016 2015 2017 2016 2015 Net amount at beginning of year $ 120,627 $ 128,244 $ 134,261 $ (9,182 ) $ (13,741 ) $ (15,869 ) Amounts arising during the period: Net (gain) loss (14,874 ) 4,370 8,680 (471 ) 313 (3,777 ) Taxes 3,869 (1,704 ) (3,386 ) 121 (122 ) 1,473 Net amount arising during the period (11,005 ) 2,666 5,294 (350 ) 191 (2,304 ) Amounts reclassified during the period: Amortization of prior service (cost) credit (288 ) (518 ) (605 ) 8,877 8,877 9,312 Amortization of actuarial loss (14,484 ) (16,339 ) (17,937 ) (1,537 ) (1,717 ) (2,047 ) Taxes 5,761 6,574 7,231 (2,863 ) (2,792 ) (2,833 ) Net reclassifications during the period (9,011 ) (10,283 ) (11,311 ) 4,477 4,368 4,432 Net amount at end of year $ 100,611 $ 120,627 $ 128,244 $ (5,055 ) $ (9,182 ) $ (13,741 ) Amounts recognized in accumulated other comprehensive loss on our Consolidated Balance Sheets Pension Plans OPEB (Dollars in thousands) 2017 2016 2017 2016 Net loss $ 100,070 $ 120,006 $ 10,165 $ 8,778 Prior service cost (credit) 541 621 (15,220 ) (17,960 ) Net amount recognized $ 100,611 $ 120,627 $ (5,055 ) $ (9,182 ) The estimated net loss and prior service cost for the defined benefit pension plans that will be amortized from accumulated other comprehensive loss into net periodic benefit cost over the next year are $16.6 million and $0.2 million, respectively. The estimated net loss and prior service credit for OPEB obligations that will be amortized from accumulated other comprehensive loss into net periodic benefit over the next year are $1.4 million and $8.9 million, respectively. EXPECTED FUNDING AND BENEFIT PAYMENTS We are required to make contributions of $10.1 million to our qualified pension plans in 2018. Our non-qualified pension plan and other postretirement employee benefit plans are unfunded and benefit payments are paid from our general assets. We estimate that we will make non-qualified pension plan and other postretirement employee benefit payments of $5.3 million in 2018, which are included below. Estimated future benefit payments, which reflect expected future service are as follows for the years indicated: (Dollars in thousands) Pension Plans OPEB 2018 $ 28,536 $ 3,704 2019 $ 28,264 $ 3,454 2020 $ 27,951 $ 3,231 2021 $ 27,588 $ 2,944 2022 $ 27,255 $ 2,760 2022–2026 $ 128,115 $ 10,557 ACTUARIAL ASSUMPTIONS The weighted average assumptions used to determine the benefit obligation as of December 31 were: Pension Plans OPEB 2017 2016 2015 2017 2016 2015 Discount rate 3.85 % 4.40 % 4.65 % 3.65 % 4.10 % 4.25 % Rate of salaried compensation increase 3.00 % 3.00 % 3.00 % — — — The weighted average assumptions used to determine the net periodic cost (benefit) for the years ended December 31 were: Pension Plans OPEB 2017 2016 2015 2017 2016 2015 Discount rate 4.40 % 4.65 % 4.25 % 4.10 % 4.25 % 3.90 % Expected return on plan assets 6.50 % 6.50 % 6.75 % — — — Rate of salaried compensation increase 3.00 % 3.00 % 3.00 % — — — The discount rate used in the determination of pension and other postretirement employee benefit obligations was calculated using hypothetical bond portfolios to match the expected benefit payments under each of our pension plans and other postretirement employee benefit obligations based on bonds available at each year-end with a rating of "AA" or better. The portfolios were well-diversified over corporate industrial, corporate financial, municipal, federal and foreign government issuers. The expected return on plan assets assumption is based upon an analysis of historical long-term returns for various investment categories, as measured by appropriate indices. These indices are weighted based upon the extent to which plan assets are invested in the particular categories in arriving at our determination of a composite expected return. The expected rate of return assumption that will be used to determine net periodic cost for 2018 is 6.25%. A decrease in the discount rate or the rate of expected return on plan assets, all other assumptions remaining the same, would increase net periodic cost. A 25 basis point decrease in the pension discount rate would increase net periodic cost by approximately $0.7 million in 2018 and increase the projected benefit obligation by approximately $10.3 million as of December 31, 2018. A 25 basis point decrease in the assumption for the expected return on plan assets would increase net periodic cost by approximately $0.7 million in 2018. The actual rates of return on plan assets may, and do, vary significantly from the assumption used. A 25 basis point decrease in the OPEB discount rate would be de minimis to the annual net periodic cost. The assumed health care cost trend rate used to calculate other postretirement employee benefit obligations as of December 31, 2017 was 8.38% for a certain group of participants under age 65 in our hourly plan and our Arkansas participants covered by a collective bargaining agreement, grading ratably to an assumption of 4.50% in 2038. The actual rates of health care cost increases may vary significantly from the assumption used because of unanticipated changes in health care costs. A one percentage point change in the health care cost trend rates would have the following effects on our December 31, 2017 Consolidated Financial Statements (Dollars in thousands) 1% Increase 1% Decrease Effect on total service cost plus interest cost $ 28 $ (24 ) Effect on accumulated postretirement benefit obligation $ 443 $ (373 )

Components of Accumulated Other

Components of Accumulated Other Comprehensive Loss	12 Months Ended
	Dec. 31, 2017
Equity [Abstract]
Components of Accumulated Other Comprehensive Loss	NOTE 13. COMPONENTS OF ACCUMULATED OTHER COMPREHENSIVE LOSS The following tables detail the changes in our accumulated other comprehensive loss (AOCL) on our Condensed Consolidated Balance Sheets (Dollars in thousands) Gains and losses on cash flow hedge Pension Plans OPEB Total Balance at January 1, 2017 $ (701 ) $ 120,627 $ (9,182 ) $ 110,744 Amounts arising during the period 145 (11,005 ) (350 ) (11,210 ) Amounts reclassified from AOCL (149 ) (9,011 ) 4,477 (4,683 ) Net change (4 ) (20,016 ) 4,127 (15,893 ) Balance at December 31, 2017 $ (705 ) $ 100,611 $ (5,055 ) $ 94,851 (Dollars in thousands) Gains and losses on cash flow hedge Pension Plans OPEB Total Balance at January 1, 2016 $ — $ 128,244 $ (13,741 ) $ 114,503 Amounts arising during the period (916 ) 2,666 191 1,941 Amounts reclassified from AOCL 215 (10,283 ) 4,368 (5,700 ) Net change (701 ) (7,617 ) 4,559 (3,759 ) Balance at December 31, 2016 $ (701 ) $ 120,627 $ (9,182 ) $ 110,744 Amounts in parenthesis indicate credits. See Note 10: Derivative Instruments Note 12: Pension and Other Postretirement Employee Benefits

Equity-Based Compensation Plans

Equity-Based Compensation Plans	12 Months Ended
	Dec. 31, 2017
Share Based Compensation [Abstract]
Equity-Based Compensation Plans	NOTE 14. EQUITY-BASED COMPENSATION PLANS As of December 31, 2017, we had two stock incentive plans under which performance stock awards (PSAs), restricted stock units (RSUs) and deferred compensation stock equivalent units were outstanding. All of these plans have received shareholder approval. We were originally authorized to issue up to 1.6 million shares and 1.0 million shares under our 2005 Stock Incentive Plan and 2014 Stock Incentive Plan, respectively. At December 31, 2017, approximately 0.4 million shares were authorized for future awards. We issue new shares of common stock to settle PSAs, RSUs and deferred compensation stock equivalent units. We estimate forfeitures each period. The following table details our compensation expense and the related income tax benefit as of December 31: (Dollars in thousands) 2017 2016 2015 Employee equity-based compensation expense: Performance stock awards $ 3,582 $ 3,437 $ 3,877 Restricted stock units 1,140 953 881 Total employee equity-based compensation expense $ 4,722 $ 4,390 $ 4,758 Deferred compensation stock equivalent units expense $ 657 $ 732 $ 376 Total tax benefit recognized for shared-based payment awards $ 379 $ 317 $ 319 PERFORMANCE STOCK AWARDS PSAs granted under the stock incentive plans have a three-year performance period and shares are issued at the end of the period if the performance measures are met. The performance measures are based on the percentile ranking of our total shareholder return relative to the total shareholder return performance of both a selected peer group of companies and a larger group of indexed companies over the three-year performance period. The number of shares actually issued, as a percentage of the amount subject to the PSA, could range from 0% to 200%. PSAs granted under our stock incentive plans do not have voting rights unless and until shares are issued upon settlement. If shares are issued at the end of the three-year performance measurement period, the recipients will receive dividend equivalents in the form of additional shares at the time of payment equal to the dividends that would have been paid on the shares earned had the recipients owned the shares during the three-year period. Therefore, the shares are not considered participating securities. A Monte Carlo simulation method is used to estimate the stock prices of Potlatch and the selected peer companies at the end of the three-year performance period. The expected volatility of each company’s stock price and covariance of returns among the peer companies are key assumptions within the Monte Carlo simulation. Historical volatility over a term similar to the performance period is considered a reasonable proxy for forecasted volatility. Likewise, because the returns of Potlatch and the peer group companies are correlated, the covariance, a measure of how two variables tend to move together, is calculated over a historical term similar to the performance period and applied in the simulations. The simulations use the stock prices of Potlatch and the peer group of companies as of the award date as a starting point. Multiple simulations are generated, resulting in share prices and total shareholder return values for Potlatch and the peer group of companies. For each simulation, the total shareholder return of Potlatch is ranked against that of the peer group of companies. The future value of the performance share unit is calculated based on a multiplier for the percentile ranking and then discounted to present value. The discount rate is the risk-free rate as of the award date for a term consistent with the performance period. Awards are also credited with dividend equivalents at the end of the performance period, and as a result, award values are not adjusted for dividends. The following table presents the key inputs used in calculating the fair value of the PSAs in 2017, 2016 and 2015, and the resulting fair values: 2017 2016 2015 Stock price as of valuation date $ 43.60 $ 25.92 $ 40.00 Risk-free rate 1.61 % 0.88 % 1.07 % Expected volatility 24.22 % 23.82 % 21.09 % Expected dividends 3.44 % 5.79 % 3.75 % Expected term (years) 3.00 3.00 3.00 Fair value of a performance share $ 53.85 $ 30.02 $ 36.71 The following table summarizes outstanding PSAs as of December 31, 2017, 2016 and 2015, and the changes during those years: 2017 2016 2015 (Dollars in thousands, except per share amounts) Shares Weighted Average Grant Date Fair Value Shares Weighted Average Grant Date Fair Value Shares Weighted Average Grant Date Fair Value Unvested shares outstanding at January 1 203,788 $ 32.59 161,049 $ 41.26 160,233 $ 53.86 Granted 78,033 $ 53.85 125,469 $ 30.02 78,974 $ 36.71 Vested (78,129 ) $ 36.71 (82,730 ) $ 45.57 (77,078 ) $ 62.78 Forfeited (3,061 ) $ 34.68 — $ — (1,080 ) $ 41.29 Unvested shares outstanding at December 31 200,631 $ 39.19 203,788 $ 32.59 161,049 $ 41.26 Total grant date fair value of share awards vested during the year $ 2,868 $ 3,770 $ 4,839 Aggregate intrinsic value of unvested share awards at December 31 $ 10,011 $ 8,488 $ 4,697 As of December 31, 2017, there was $4.0 million of unrecognized compensation cost related to unvested PSAs, which is expected to be recognized over a weighted average period of 1.4 years. RESTRICTED STOCK UNITS Our 2005 Stock Incentive Plan and 2014 Stock Incentive Plan also allow for awards to be issued in the form of RSU grants. During 2017, 2016 and 2015, certain officers and other employees of the company were granted RSU awards that will accrue dividend equivalents based on dividends paid during the RSU vesting period. The dividend equivalents will be converted into additional RSUs that will vest in the same manner as the underlying RSUs to which they relate. Therefore, the shares are not considered participating securities. The terms of the awards state that the RSUs will vest in a given time period of one to three years, and the terms of certain awards follow a vesting schedule within the given time period. The following table summarizes outstanding RSU awards as of December 31, 2017, 2016 and 2015, and the changes during those years: 2017 2016 2015 (Dollars in thousands, except per share amounts) Shares Weighted Average Grant Date Fair Value Shares Weighted Average Grant Date Fair Value Shares Weighted Average Grant Date Fair Value Unvested shares outstanding at January 1 71,420 $ 31.61 44,531 $ 40.95 32,455 $ 42.24 Granted 26,507 $ 43.64 43,320 $ 26.08 27,820 $ 39.99 Vested (29,039 ) $ 39.65 (16,431 ) $ 39.92 (15,385 ) $ 44.50 Forfeited (1,017 ) $ 31.63 — $ — (359 ) $ 40.27 Unvested shares outstanding at December 31 67,871 $ 32.87 71,420 $ 31.61 44,531 $ 40.95 Total grant date fair value of RSU awards vested during the year $ 1,151 $ 656 $ 289 Aggregate intrinsic value of unvested RSU awards at December 31 $ 3,387 $ 2,975 $ 1,347 As of December 31, 2017, there was $1.1 million of total unrecognized compensation cost related to outstanding RSU awards, which is expected to be recognized over a weighted average period of 1.4 years. DEFERRED COMPENSATION STOCK EQUIVALENT UNITS A long-term incentive award is granted annually to our directors, and payable upon a director's separation from service. Directors may also elect to defer their annual retainers, payable in the form of stock. All stock unit equivalent accounts are credited with dividend equivalents. As of December 31, 2017, there were 141,938 shares outstanding that will be distributed in the future to directors as common stock. Issuance of restricted stock units awarded to certain officers and employees may also be deferred. All stock unit equivalent accounts are credited with dividend equivalents. As of December 31, 2017, there were 74,067 RSUs which had vested, but issuance of the related stock had been deferred.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Income Taxes	NOTE 15. INCOME TAXES As a REIT, we generally are not subject to federal and state corporate income taxes on income from investments in real estate that we distribute to our shareholders. We are required to pay federal and state corporate income taxes on income from our non-real estate investments which are held in taxable REIT subsidiaries (TRS). These activities are principally comprised of our wood products manufacturing operations and certain real estate investments held for sale. As of January 1, 2016, we are no longer subject to corporate income taxes on built-in gains, the excess of fair market value over tax basis, on sales of real property held at the time of our REIT conversion. On December 22, 2017, H.R. 1, Tax Cuts and Jobs Act (the Act) was enacted and included broad tax reforms. Under the provisions of the Act, the U.S. corporate tax rate decreased from 35% to 21% effective January 1, 2018, which required a remeasurement of our deferred tax assets and liabilities as of the date of enactment. Accordingly, net deferred tax assets, including the related valuation allowance, were reduced by $10.7 million and the change was recorded as an increase to the 2017 tax provision. Income tax expense consists of the following for the years ended December 31: (Dollars in thousands) 2017 2016 2015 Current $ 16,657 $ (6,178 ) $ 128 Deferred 14,325 2,143 1,097 Net operating loss carryforwards 1,039 (290 ) (6,793 ) Income tax provision (benefit) $ 32,021 $ (4,325 ) $ (5,568 ) Income tax expense differs from the amount computed by applying the statutory federal income tax rate of 35% to income before income taxes due to the following for the years ended December 31: (Dollars in thousands) 2017 2016 2015 U.S. federal statutory income tax $ 41,466 $ 2,314 $ 9,151 REIT income not subject to federal income tax (20,651 ) (7,199 ) (14,110 ) U.S. tax rate change on deferred tax assets and liabilities 10,528 — — Intercompany profit-in-inventory elimination adjustment — 1,465 — Change in valuation allowance 140 162 488 State income taxes, net of federal income tax 2,608 (740 ) (838 ) Domestic production activities deduction (1,511 ) (2 ) — Permanent book-tax differences (252 ) (218 ) (70 ) Research and development credits (294 ) (689 ) — All other items (13 ) 582 (189 ) Income tax provision (benefit) $ 32,021 $ (4,325 ) $ (5,568 ) Effective tax rate 27.0 % (65.4 %) (21.3 %) The tax effects of significant temporary differences creating deferred tax assets and liabilities at December 31 were: (Dollars in thousands) 2017 2016 Deferred tax assets: Pensions $ 19,439 $ 37,423 Other postretirement employee benefits 7,891 13,002 Net operating loss carryforwards 54 983 Inventories 353 443 Tax credits 2,443 2,207 Nondeductible accruals 2,566 2,067 Incentive compensation 1,131 1,643 Employee benefits 1,037 1,444 Other 88 120 Total deferred tax assets 35,002 59,332 Valuation allowance (790 ) (650 ) Deferred tax assets, net of valuation allowance 34,212 58,682 Deferred tax liabilities: Timber and timberlands, net (1,432 ) (2,165 ) Property, plant and equipment, net (12,683 ) (14,018 ) Other (301 ) (448 ) Total deferred tax liabilities (14,416 ) (16,631 ) Deferred tax assets, net $ 19,796 $ 42,051 As of December 31, 2017, we had no federal net operating loss carryforwards; state net operating loss and capital loss carryforwards were $1.2 million that expire from 2021 through 2030; and Idaho Investment Tax Credits were $3.1 million that expire from 2019 through 2031. We use the flow-through method of accounting for investment tax credits. With the exception of the valuation allowance discussed below, we believe it is more likely than not that we will have sufficient future taxable income to realize our deferred tax assets. Due to the impact of the change in federal rate under the Act, the valuation allowance on our deferred tax assets increased during 2017 by $0.1 million, and was $0.8 million as of December 31, 2017. The valuation allowance is related to certain Idaho Investment Tax Credit carryforwards we expect will expire prior to realization. During 2016, the valuation allowance increased from $0.5 to $0.7 million due to the actual use and expected future use of certain Idaho Investment Tax Credits. The following table summarizes the tax years subject to examination by major taxing jurisdictions: Jurisdiction Years Federal 2013 — 2017 Arkansas 2014 — 2017 Michigan 2013 — 2017 Minnesota 2013 — 2017 Idaho 2014 — 2017 As of December 31, 2017, we had $0.6 million of unrecognized tax benefits which, if recognized, would impact the effective tax rate. There was $0.9 unrecognized tax benefits at December 31, 2016 and no unrecognized tax benefits at December 31, 2015. We currently believe there is a reasonable possibility that the amounts of unrecognized tax benefits will significantly decrease in the next 12 months based on the closing of certain ongoing state tax examinations. A reconciliation of the beginning and ending unrecognized tax benefits is as follows: (Dollars in thousands) 2017 2016 Balance at January 1 $ 850 $ — Additions for tax positions of prior years 8 850 Reduction for tax positions of prior years (294 ) — Balance at December 31 $ 564 $ 850 We reflect accrued interest related to tax obligations, as well as penalties, in our provision for income taxes. For the years ended December 31, 2017, 2016 and 2015, we recognized insignificant amounts related to interest and penalties in our tax provision. At December 31, 2017 and 2016, we had insignificant amounts of accrued interest related to tax obligations and no accrued interest receivable with respect to open tax refunds.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2017
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	NOTE 16. COMMITMENTS AND CONTINGENCIES OPERATING LEASES We have operating leases primarily for office space, machinery and equipment expiring at various dates through 2033. We expect that most leases will be renewed or replaced in the normal course of business as they expire. As of December 31, 2017, the future minimum rental payments required under our operating leases are as follows: (Dollars in thousands) 2018 $ 4,570 2019 3,518 2020 2,662 2021 1,771 2022 874 2023 and thereafter 992 Total $ 14,387 Operating lease expense was $4.5 million, $4.2 million and $4.6 million for the years ended December 31, 2017, 2016 and 2015, respectively. LEGAL MATTERS In January 2007, the Environmental Protection Agency (EPA) notified us that we are a potentially responsible party under the Comprehensive Environmental Response, Compensation and Liability Act of 1980 (CERCLA) and the Clean Water Act for cleanup of a site known as Avery Landing in northern Idaho. At the time we owned a portion of the land at the Avery Landing site, which we acquired in 1980 from the Milwaukee Railroad. The land we owned at the site and adjacent properties were contaminated with petroleum as a result of the Milwaukee Railroad's operations at the site prior to 1980. On July 5, 2011, the EPA issued an Action Memorandum for the Avery Landing site selecting contaminant extraction and off-site disposal as the remedial alternative. On May 23, 2012, we signed a consent order with the EPA pursuant to which we agreed to provide $1.75 million in funding for EPA cleanup on a portion of our property (including the adjacent riverbank owned by the Idaho Department of Lands). The EPA cleanup was completed in October 2012. On April 4, 2013, the EPA issued a unilateral administrative order requiring us to remediate the portion of the Avery Landing site that we owned. Our remediation was completed in October 2013. On September 25, 2015, the EPA sent us a letter asserting that the EPA and the Department of Transportation (the current owner of a portion of the adjacent property remediated by the EPA) (DOT) had incurred $9.8 million in unreimbursed response costs associated with the site and that we were liable for such costs. We have executed six tolling agreements with the EPA and DOT suspending the statute of limitations on the claim until March 31, 2018 in order to facilitate negotiations of a final settlement and release. We accrued $0.2 million for this matter in the first quarter of 2016, an additional $0.8 million in the second quarter of 2016 and an additional $5.0 million in the third quarter of 2017. On February 9, 2018, we executed a Consent Decree with the United States, acting on behalf of the Environmental Protection Agency and Department of Transportation, settling the United States’ claims against us for $6 million. On February 12, 2018 the United States filed a lawsuit against us in the United States District Court for the District of Idaho and lodged the Consent Decree with the Court. The United States will publish a Notice of Lodging of the Consent Decree in the Federal Register and after the expiration of a required 30-day public comment period, will advise the Court whether the Consent Decree may be entered. If the Consent Decree is not approved by the Court following the 30-day public comment period, we reserve all defenses to liability and the right to pursue all potentially responsible parties.

Segment Information

Segment Information	12 Months Ended
	Dec. 31, 2017
Segment Reporting Information Additional Information [Abstract]
Segment Information	NOTE 17. SEGMENT INFORMATION Our businesses are organized into three reportable operating segments: Resource, Wood Products and Real Estate. Management activities include planting and harvesting trees and building and maintaining roads. The Resource segment also generates revenues from non-timber resources such as hunting leases, recreation permits and leases, mineral rights leases, biomass production and carbon sequestration. The Wood Products segment manufactures and markets lumber and plywood. The business of our Real Estate segment consists primarily of the sale of land holdings deemed non-strategic or identified as having higher and better use alternatives. The Real Estate segment engages in limited real estate subdivision activities through Potlatch TRS. The reporting segments follow the same accounting policies used for our Consolidated Financial Statements The following table presents business segment information for each of the past three years. Corporate information is included to reconcile segment data to the Consolidated Financial Statements (Dollars in thousands) 2017 2016 2015 Revenues: Resource $ 278,199 $ 256,163 $ 263,875 Wood Products 441,157 367,426 336,214 Real Estate 30,655 32,604 28,989 750,011 656,193 629,078 Intersegment Resource revenues 1 (71,416 ) (57,094 ) (53,742 ) Total consolidated revenues $ 678,595 $ 599,099 $ 575,336 Income (loss) before income taxes: Resource $ 106,105 $ 81,918 $ 76,350 Wood Products 72,166 24,587 (5,235 ) Real Estate 2 18,576 (29,495 ) 16,849 Eliminations and adjustments (2,705 ) (3,001 ) 3,283 194,142 74,009 91,247 Corporate (48,619 ) (38,455 ) (32,340 ) Operating income 145,523 35,554 58,907 Interest expense, net (27,049 ) (28,941 ) (32,761 ) Income before income taxes $ 118,474 $ 6,613 $ 26,146 Depreciation, depletion and amortization: Resource $ 20,476 $ 24,090 $ 28,807 Wood Products 7,347 7,357 6,810 Real Estate 2 4 56 27,825 31,451 35,673 Corporate 607 760 951 Bond discount and deferred loan fees 1,480 1,979 1,481 Total depreciation, depletion and amortization $ 29,912 $ 34,190 $ 38,105 Basis of real estate sold: Real Estate $ 7,114 $ 8,518 $ 7,394 Elimination and adjustments (287 ) (507 ) (382 ) Total basis of real estate sold $ 6,827 $ 8,011 $ 7,012 Assets: Resource and Real Estate 3 $ 670,240 $ 662,852 $ 837,630 Wood Products 154,479 150,855 131,103 824,719 813,707 968,733 Corporate 128,360 113,974 47,879 Total consolidated assets $ 953,079 $ 927,681 $ 1,016,612 Capital Expenditures: 4 Resource $ 15,120 $ 13,311 $ 13,497 Wood Products 10,723 5,491 18,482 Real Estate 87 111 184 25,930 18,913 32,163 Corporate 2,132 375 569 Total capital expenditures $ 28,062 $ 19,288 $ 32,732 1 2 3 Assets are shown on a combined basis for the Resource and Real Estate segments, as we do not report assets separately to management for these segments. 4 Excludes the acquisition of timber and timberlands. All of our wood products facilities and all other assets are located within the continental United States. Geographic information regarding our revenues is as follows: (Dollars in thousands) 2017 2016 2015 United States $ 676,956 $ 597,899 $ 573,398 Canada 481 173 851 Mexico 1,158 1,027 919 Other — — 168 Total consolidated revenues $ 678,595 $ 599,099 $ 575,336 One customer within our Resource segment accounted for slightly more than 10% of our total consolidated revenues in the years ended December 31, 2017, 2016 and 2015.

Financial Results by Quarter (U

Financial Results by Quarter (Unaudited)	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Data [Abstract]
Financial Results by Quarter (Unaudited)	NOTE 18. FINANCIAL RESULTS BY QUARTER (UNAUDITED) Three Months Ended March 31 June 30 September 30 December 31 (Dollars in thousands, except per share amounts) 2017 2016 2017 2016 2017 2016 2017 2016 Revenues $ 149,681 $ 127,896 $ 163,229 $ 141,495 $ 190,441 $ 174,027 $ 175,244 $ 155,681 Operating income (loss) $ 23,909 $ 5,072 $ 40,773 $ (34,228 ) $ 43,793 $ 38,994 $ 37,048 $ 25,716 Net income (loss) $ 16,921 $ 157 $ 24,244 $ (31,238 ) $ 33,700 $ 27,646 $ 11,588 $ 14,373 Net income (loss) per share 1 Basic $ 0.41 $ — $ 0.59 $ (0.77 ) $ 0.83 $ 0.68 $ 0.28 $ 0.35 Diluted $ 0.41 $ — $ 0.59 $ (0.77 ) $ 0.82 $ 0.68 $ 0.28 $ 0.35 1 Per share amounts are computed independently for each of the quarters presented. Therefore, the sum of the quarterly per share amounts may not equal the total computed for the year. Our Quarterly Reports on Form 10-Q, as filed with the Securities and Exchange Commission, include the quarterly results for the first nine months of each respective year. During the fourth quarter of 2017, we incurred $3.4 million in merger-related costs associated with the pending merger with Deltic. See Note 2: Pending Merger with Deltic

Summary of Significant Accoun28

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
General	GENERAL We are primarily engaged in activities associated with timberland management, including the sale of timber, the management of approximately 1.4 million acres of timberlands and the purchase and sale of timberlands. We are also engaged in the manufacture and sale of wood products. Our timberlands and all of our wood products facilities are located within the continental United States. The primary market for our products is the United States. We converted to a Real Estate Investment Trust (REIT) effective January 1, 2006.
Consolidation	CONSOLIDATION The Consolidated Financial Statements
Significant Estimates	SIGNIFICANT ESTIMATES The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America, which we refer to in this report as U.S. GAAP, requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates and assumptions. Significant estimates include timber volumes, pension and postretirement obligation assumptions, contingent liabilities and the fair value of derivative instruments. These significant estimates are described in further detail below.
Cash and Cash Equivalents	Cash and Cash Equivalents Cash equivalents are investments that are highly liquid with maturities of three months or less when purchased.
Inventories	INVENTORIES For most of our operations, the last-in, first-out method is used to determine the cost of logs, lumber and plywood. The average cost method is used to determine the cost of all other inventories. Inventories are stated at the lower of cost or net realizable value. Expenses associated with idle capacity or other curtailments of production are reflected in cost of goods sold in the periods incurred.
Property, Plant and Equipment	PROPERTY, PLANT AND EQUIPMENT Property, plant and equipment are valued at cost less accumulated depreciation. Depreciation of buildings, equipment and other depreciable assets is determined using the straight-line method of depreciation. Major improvements and replacements of property are capitalized. Maintenance, repairs and minor improvements and replacements are expensed. Upon retirement or other disposition of property, applicable cost and accumulated depreciation are removed from the accounts. Any gains or losses are included in earnings.
Timber and Timberlands	TIMBER AND TIMBERLANDS Timber and timberlands are valued at cost less accumulated depletion and amortization. We capitalize costs related to stand establishment, which include the preparation of the land for planting, seeds or seedlings and tree planting costs, which include third-party labor costs, materials and other contract services. Upon completion of planting activities and field inspection to confirm the planting operation was successful, a plantation will be considered “established.” Subsequent expenditures to maintain the integrity or enhance the growth of an established plantation or stand are expensed. Post-establishment expenses include vegetation control, fertilization, thinning operations and the replanting of seedlings lost through mortality. Forest management costs are considered current operating expenses and include property taxes and insurance, silviculture costs incurred subsequent to stand establishment, cruising (physical inventory), property maintenance, salaries, supplies, travel, record-keeping, fire protection and other normal recurring administrative personnel costs. Timberland acquisitions are capitalized based on the relative appraised values of timberland, merchantable sawlogs, merchantable pulpwood, pre-production timber (young growth that is not yet merchantable timber), logging roads and other land improvements. The estimated volume of current standing merchantable timber inventory, which is a component of calculating our depletion rates, is updated at least annually to reflect increases due to the reclassification of pre-production timber to merchantable timber when it meets defined diameter specifications, the annual growth of merchantable timber and the acquisition of additional merchantable timber, decreases due to timber harvests and land sales and changes resulting from other factors, such as environmental or casualty losses. Timber volumes are estimated from cruises of the timber tracts, which are completed on our timberlands on approximately a five to ten year cycle. Depletion represents the amount charged to expense as timber is harvested. Rates at which timber is depleted are calculated annually for each of our depletion pools by dividing the beginning of year balance of the merchantable timber accounts by the forest inventory volume, after inventory updates. The base cost of logging roads, such as clearing, grading and ditching, is not amortized and remains a capitalized item until disposition. Other portions of the initial logging road cost, such as bridges, culverts and gravel surfacing are amortized over their useful lives, which range from 5 to 20 years. Costs associated with temporary logging road spurs, which are typically used for one harvest season, are expensed as incurred.
Real Estate Sales	REAL ESTATE SALES Sales of non-core timberland are considered to be part of our normal operations. We therefore classify revenue and costs associated with real estate sold in revenues and cost of goods sold, respectively, in our Consolidated Statements of Income Consolidated Statements of Cash Flows . Sales of large parcels of property, such as our sale of central Idaho timberlands in 2016, which do not represent our core operations and are of such a size as to not be indicative of our ongoing operations, are presented as a net gain or loss in our Consolidated Statements of Income Consolidated Statements of Cash Flows .
Long-Lived Assets	LONG-LIVED ASSETS Our long-lived assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable, as measured by its undiscounted estimated future cash flows. We use our operational budgets to estimate future cash flows. The estimates are adjusted periodically to reflect changing business conditions. Impaired assets are written down to fair value. Assets to be disposed of are reported at the lower of carrying amount or fair value less cost to sell. We recognize a liability and an asset equal to the fair value of our legal obligations to perform asset retirement activities if the amount can be reasonably estimated. We review these obligations annually and do not expect them to have a material effect on our financial position, results of operations or cash flows.
Income Taxes	INCOME TAXES We use the asset and liability method of accounting for income taxes. Under this method, deferred tax assets and liabilities are recognized for the estimated future tax consequences attributable to differences between the financial statement carrying amounts of assets and liabilities and their respective tax bases, operating loss carryforwards and tax credit carryforwards. Deferred tax assets and liabilities are measured pursuant to tax laws using rates expected to apply to taxable income in the years in which the temporary differences are expected to be recovered or settled. We recognize the effect of a change in income tax rates on deferred tax assets and liabilities in the Consolidated Statements of Income Consolidated Statements of Comprehensive Income
Revenue Recognition	REVENUE RECOGNITION We recognize revenue from the sale of timber when risk of loss transfers to the buyer and the quantity sold is determinable. These sales usually take the form of delivered logs, pay-as-cut stumpage contracts, lump sum stumpage contracts or timber deeds. On delivered log sales, revenue includes amounts billed for logging and hauling and is recognized at the point the logs are delivered and scaled. Revenue is recognized on timber deeds and lump sum stumpage contracts generally upon closing or when the contracts are effective, which is the point at which the buyer assumes risk of loss associated with the standing timber. We recognize revenue from the sale of manufactured wood products and residual by-products when there is persuasive evidence of a sales agreement, the price to the customer is fixed and determinable, collection is reasonably assured and title and the risk of loss passes to the customer. Shipping terms generally indicate when title and the risk of loss have passed. Revenue is recognized at shipment when shipping terms are FOB (free on board) shipping point. For sales where shipping terms are FOB destination, revenue is recognized when the goods are received by the customer. We receive cash consideration in full and recognize revenue at closing on substantially all of our real estate sales. While sales taxes are not typical, in the event sales taxes are collected, revenue is recognized net of any sales tax and sales taxes are recorded as a current liability and remitted to the appropriate governmental entities. Costs for shipping and handling are included in cost of goods sold in our Consolidated Statements of Income
Equity-Based Compensation	EQUITY-BASED COMPENSATION Equity-based awards are measured at fair value on the dates they are granted or modified. These measurements establish the cost of the equity-based awards for accounting purposes. The cost of the equity-based award is then recognized in the Consolidated Statements of Income Note 14: Equity-Based Compensation Plans
New Accounting Pronouncements	NEW ACCOUNTING PRONOUNCEMENTS In March 2016, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2016-09, Improvements to Employee Share-Based Payment Accounting In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers: Topic 606 Revenue from Contracts with Customers (Topic 606), Deferral of the Effective Date In March 2017, the FASB issued ASU No. 2017-07, Compensation – Retirement Benefits (Topic 715), Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost In October 2016, the FASB issued ASU No. 2016-16, Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other Than Inventory In January 2017, the FASB issued ASU 2017-1, Business Combinations (Topic 805): Clarifying the Definition of a Business In August 2017, the FASB issued ASU No. 2017-12, Derivatives and Hedging (Topic 815), Targeted Improvements to Accounting for Hedging Activities In February 2016, the FASB issued ASU No. 2016-02, Leases In February 2018, the FASB issued ASU No. 2018-2, Income Statement – Reporting Comprehensive Income (Topic 220), Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income Note 15: Income Taxes
Reclassification	RECLASSIFICATIONS Prior year environmental charges for Avery Landing within the Consolidated Statements of Income Prior year receivables not due from customers within the Consolidated Balance Sheets Note 7: Other Current Assets Certain 2016 and 2015 amounts within cash flows from operations on the Consolidated Statements of Cash Flows

Earnings per Share (Tables)

Earnings per Share (Tables)	12 Months Ended
	Dec. 31, 2017
Earnings Per Share Basic Other Disclosures [Abstract]
Reconciliation of Number of Common Shares Used in Calculating Basic and Diluted EPS	The following table reconciles the number of shares used in calculating the basic and diluted earnings per share for the years ended December 31: (Dollars in thousands, except per share amounts) 2017 2016 2015 Net income $ 86,453 $ 10,938 $ 31,714 Basic weighted-average shares outstanding 40,824,420 40,797,806 40,842,126 Incremental shares due to: Performance shares 362,509 200,164 122,334 Restricted stock units 40,459 35,470 23,359 Diluted weighted-average shares outstanding 41,227,388 41,033,440 40,987,819 Basic net income per share $ 2.12 $ 0.27 $ 0.78 Diluted net income per share $ 2.10 $ 0.27 $ 0.77

Inventories (Tables)

Inventories (Tables)	12 Months Ended
	Dec. 31, 2017
Inventory Disclosure [Abstract]
Schedule of Inventories	(Dollars in thousands) 2017 2016 Logs $ 20,133 $ 23,342 Lumber, plywood and veneer 20,889 20,500 Materials and supplies 9,110 8,780 $ 50,132 $ 52,622 Valued at lower of cost or net realizable value: Last-in, first-out basis $ 25,127 $ 29,769 Average cost basis 25,005 22,853 Total inventories $ 50,132 $ 52,622

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	12 Months Ended
	Dec. 31, 2017
Property Plant And Equipment [Abstract]
Schedule of Property, Plant and Equipment	(Dollars in thousands) Range of useful lives 2017 2016 Land $ 4,707 $ 4,712 Buildings and improvements 10-40 years 55,734 54,448 Machinery and equipment 2-25 years 197,648 190,316 Construction in progress 1,348 1,437 259,437 250,913 Less: accumulated depreciation (182,208 ) (178,093 ) Total property, plant and equipment, net $ 77,229 $ 72,820

Timber and Timberlands(Tables)

Timber and Timberlands(Tables)	12 Months Ended
	Dec. 31, 2017
Timber And Timberlands [Abstract]
Schedule of Timber and Timberlands	(Dollars in thousands) 2017 2016 Timber and timberlands $ 581,648 $ 572,273 Logging roads 72,828 69,583 Total timber and timberlands, net $ 654,476 $ 641,856
Schedule of Future Payments Due Under Timber Cutting Contracts	Future payments due under timber cutting contracts as of December 31, 2017 are as follows: (Dollars in thousands) 2018 $ 11,280 2019 2,730 2020 1,085 2021 5,370 2022 281 Total $ 20,746

Other Current Assets (Tables)

Other Current Assets (Tables)	12 Months Ended
	Dec. 31, 2017
Other Assets [Abstract]
Schedule of Other Current Assets	(Dollars in thousands) 2017 2016 Real estate held for sale $ 7,721 $ 9,184 Prepaid expenses 2,862 1,939 Other receivables 882 2,442 Interest rate swaps 13 32 Total other current assets $ 11,478 $ 13,597

Accounts Payable and Accrued 34

Accounts Payable and Accrued Liabilities (Tables)	12 Months Ended
	Dec. 31, 2017
Accounts Payable And Accrued Liabilities Current And Noncurrent [Abstract]
Schedule of Accounts Payable and Accrued Liabilities	(Dollars in thousands) 2017 2016 Accrued payroll and benefits $ 18,110 $ 13,634 Accounts payable 9,361 8,382 Accrued interest 6,385 6,237 Avery Landing accrual 6,000 1,022 Accrued taxes 5,103 4,956 Other current liabilities 10,242 9,479 Total accounts payable and accrued liabilities $ 55,201 $ 43,710

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Schedule of Long-term Debt Instruments	(Dollars in thousands) 2017 2016 Term loans $ 343,500 $ 349,500 Senior notes 150,000 150,000 Revenue bonds 65,735 65,735 Medium-term notes 17,250 22,250 Long-term principal 576,485 587,485 Interest rate swaps (373 ) 247 Debt issuance costs (2,321 ) (3,015 ) Unamortized discounts (472 ) (729 ) Total long-term debt (includes current portion) 573,319 583,988 Less current portion of long-term debt (14,263 ) (11,032 ) Long-term debt $ 559,056 $ 572,956
Schedule of Maturities of Long-term Debt	Scheduled principal payments due on long-term debt as of December 31, 2017 are as follows: (Dollars in thousands) 2018 $ 14,250 2019 190,000 2020 46,000 2021 40,000 2022 43,000 Thereafter 243,235 Total $ 576,485

Derivative Instruments (Tables)

Derivative Instruments (Tables)	12 Months Ended
	Dec. 31, 2017
Derivative Instrument Detail [Abstract]
Fair Value of Cash Flow and Fair Value Derivative Instruments	The fair values of our cash flow and fair value derivative instruments on our Consolidated Balance Sheets Asset Derivatives Liability Derivatives (Dollars in thousands) Location 2017 2016 Location 2017 2016 Derivatives designated in fair value hedging relationships: Interest rate contracts Other assets, current $ 13 $ 32 $ — $ — Interest rate contracts Other assets, non-current 215 Other long-term obligations 91 $ 13 $ 247 $ — $ 91 Derivatives designated in cash flow hedging relationships: Interest rate contracts Other assets, non-current $ 1,156 $ 1,148 $ — $ —
Effect of Derivatives on Consolidated Statements of Income	The following table details the effect of derivatives on our Consolidated Statements of Income (Dollars in thousands) Location 2017 2016 2015 Derivatives designated in fair value hedging relationships: Interest rate contracts Realized gain on interest rate contracts 1 Interest expense $ 413 $ 805 $ 1,534 Derivatives designated in cash flow hedging relationships: Interest rate contracts Gain (loss) recognized in other comprehensive income, net of tax (effective portion) $ (145 ) $ 916 $ — Loss reclassified from accumulated other comprehensive income (effective portion) 1 Interest expense $ (149 ) $ (215 ) $ — Derivatives not designated as hedging instruments: Lumber price contracts Realized gain on lumber price swap Gain on lumber price swap $ 1,088 $ — $ — 1 Realized gains and losses on interest rate contracts consist of net cash received or paid and interest accruals on the interest rate swaps during the periods. Net cash received or paid is included in the supplemental cash flow information within interest, net of amounts capitalized in the Consolidated Statements of Cash Flows .

Financial Instruments (Tables)

Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2017
Derivative Instrument Detail [Abstract]
Estimated Fair Value of Financial Instruments	Estimated fair values of our financial instruments as of December 31 are as follows: 2017 2016 (Dollars in thousands) Carrying Amount Fair Value Carrying Amount Fair Value Cash and cash equivalents (Level 1) $ 120,457 $ 120,457 $ 82,584 $ 82,584 Derivative assets related to interest rate swaps (Level 2) $ 1,169 $ 1,169 $ 1,395 $ 1,395 Derivative liabilities related to interest rate swaps (Level 2) $ — $ — $ (91 ) $ (91 ) Long-term debt, including current portion (Level 2): Term loans $ (343,500 ) $ (345,222 ) $ (349,500 ) $ (350,909 ) Senior notes (149,528 ) (161,063 ) (149,271 ) (164,250 ) Revenue bonds (65,735 ) (63,967 ) (65,735 ) (62,205 ) Medium-term notes (17,250 ) (18,227 ) (22,250 ) (23,926 ) Total long-term debt 1 $ (576,013 ) $ (588,479 ) $ (586,756 ) $ (601,290 ) Company owned life insurance (COLI) (Level 3) $ 1,996 $ 1,996 $ 70 $ 70 1 The carrying amount of long-term debt includes principal and unamortized discounts

Savings Plans, Pension Plans 38

Savings Plans, Pension Plans and Other Postretirement Employee Benefits (Tables)	12 Months Ended
	Dec. 31, 2017
General Discussion Of Pension And Other Postretirement Benefits [Abstract]
Schedule of Changes in Projected Benefit Obligations	The change in benefit obligation, change in plan assets and funded status for company-sponsored benefit plans and obligations are as follows: Pension Plans OPEB (Dollars in thousands) 2017 2016 2017 2016 Benefit obligation at beginning of year $ (385,461 ) $ (382,071 ) $ (33,337 ) $ (35,471 ) Service cost (6,753 ) (6,508 ) (14 ) (14 ) Interest cost (16,096 ) (17,020 ) (1,262 ) (1,421 ) Actuarial (loss) gain (15,876 ) (13,997 ) 471 (313 ) Benefits paid 31,815 34,135 3,793 3,882 Benefit obligation at end of year $ (392,371 ) $ (385,461 ) $ (30,349 ) $ (33,337 ) Fair value of plan assets at beginning of year $ 289,675 $ 292,200 $ — $ — Actual return on plan assets 49,158 28,626 — — Employer contributions and benefit payments 6,844 2,984 3,794 3,882 Benefits paid (31,815 ) (34,135 ) (3,794 ) (3,882 ) Fair value of plan assets at end of year $ 313,862 $ 289,675 $ — $ — Amounts recognized in the consolidated balance sheets: Current liabilities $ (1,629 ) $ (1,824 ) $ (3,705 ) $ (4,015 ) Noncurrent liabilities (76,880 ) (93,962 ) (26,644 ) (29,322 ) Funded status $ (78,509 ) $ (95,786 ) $ (30,349 ) $ (33,337 )
Schedule of Actual Asset Allocations of the Pension Benefit Plans' Assets	The asset allocations of the pension benefit plans’ assets at December 31 by asset category are as follows: Pension Plans Asset Category 2017 2016 Domestic and international equities 37 % 36 % Fixed income securities 47 48 Other (includes cash and cash equivalents and alternatives) 16 16 Total 100 % 100 %
Schedule of Allocation of Plan Assets	Fair value measurements are as follows: (Dollars in thousands) December 31, 2017 Asset Category Level 1 Level 2 Total Cash and cash equivalents $ 3,004 $ — $ 3,004 Domestic equity securities 1 29,178 28,382 57,560 International equity securities 2 — 28,413 28,413 Emerging markets 3 12 29,245 29,257 Fixed income securities 4 148,833 — 148,833 Alternatives 5 — 46,795 46,795 Total $ 181,027 $ 132,835 $ 313,862 (Dollars in thousands) December 31, 2016 Asset Category Level 1 Level 2 Total Cash and cash equivalents $ 2,845 $ — $ 2,845 Domestic equity securities 1 25,409 26,279 51,688 International equity securities 2 — 26,555 26,555 Emerging markets 3 12 26,391 26,403 Fixed income securities 4 138,897 — 138,897 Alternatives 5 — 43,287 43,287 Total $ 167,163 $ 122,512 $ 289,675 1 Level 1 assets are managed investments in U.S. small/mid-cap equities that track the Russell 2500 Growth index or Russell 2500 Value index. Level 2 assets are collective investments, which are invested in U.S. large-cap equities that track the S&P 500. 2 3 Level 1 assets are mutual funds which are invested in the common stock of companies located (or with primary operations) in emerging markets that track the MSCI Emerging Markets index. Level 2 assets are collective investments in the common stock of companies located (or with primary operations) in emerging markets that track the MSCI Emerging Markets index. 4 5 Level 2 assets are collective investments in inflation-indexed bonds, securities of real estate companies, commodity index-linked notes, fixed income securities, foreign currencies, securities of natural resource companies, master limited partnerships, publicly listed infrastructure companies, floating-rate debt, securities of global agriculture companies and securities of global timber companies.
Pre-tax Components of Net Periodic Cost (Benefit)	Pre-tax components of net periodic cost (benefit) recognized in our Consolidated Statements of Income Pension Plans OPEB (Dollars in thousands) 2017 2016 2015 2017 2016 2015 Service cost $ 6,753 $ 6,508 $ 6,159 $ 14 $ 14 $ 22 Interest cost 16,096 17,020 17,012 1,262 1,421 1,456 Expected return on plan assets (18,406 ) (18,999 ) (20,804 ) — — — Amortization of prior service cost (credit) 288 518 605 (8,877 ) (8,877 ) (9,312 ) Amortization of actuarial loss 14,484 16,339 17,937 1,537 1,717 2,047 Net periodic cost (benefit) $ 19,215 $ 21,386 $ 20,909 $ (6,064 ) $ (5,725 ) $ (5,787 )
Schedule of Amounts Recognized in Other Comprehensive Income (Loss)	Other amounts recognized in our Consolidated Statements of Comprehensive Income Pension Plans OPEB (Dollars in thousands) 2017 2016 2015 2017 2016 2015 Net amount at beginning of year $ 120,627 $ 128,244 $ 134,261 $ (9,182 ) $ (13,741 ) $ (15,869 ) Amounts arising during the period: Net (gain) loss (14,874 ) 4,370 8,680 (471 ) 313 (3,777 ) Taxes 3,869 (1,704 ) (3,386 ) 121 (122 ) 1,473 Net amount arising during the period (11,005 ) 2,666 5,294 (350 ) 191 (2,304 ) Amounts reclassified during the period: Amortization of prior service (cost) credit (288 ) (518 ) (605 ) 8,877 8,877 9,312 Amortization of actuarial loss (14,484 ) (16,339 ) (17,937 ) (1,537 ) (1,717 ) (2,047 ) Taxes 5,761 6,574 7,231 (2,863 ) (2,792 ) (2,833 ) Net reclassifications during the period (9,011 ) (10,283 ) (11,311 ) 4,477 4,368 4,432 Net amount at end of year $ 100,611 $ 120,627 $ 128,244 $ (5,055 ) $ (9,182 ) $ (13,741 )
Schedule of Accumulated Other Comprehensive Income (Loss)	Amounts recognized in accumulated other comprehensive loss on our Consolidated Balance Sheets Pension Plans OPEB (Dollars in thousands) 2017 2016 2017 2016 Net loss $ 100,070 $ 120,006 $ 10,165 $ 8,778 Prior service cost (credit) 541 621 (15,220 ) (17,960 ) Net amount recognized $ 100,611 $ 120,627 $ (5,055 ) $ (9,182 )
Schedule of Expected Future Benefit Payments	Estimated future benefit payments, which reflect expected future service are as follows for the years indicated: (Dollars in thousands) Pension Plans OPEB 2018 $ 28,536 $ 3,704 2019 $ 28,264 $ 3,454 2020 $ 27,951 $ 3,231 2021 $ 27,588 $ 2,944 2022 $ 27,255 $ 2,760 2022–2026 $ 128,115 $ 10,557
Weighted Average Assumptions Used to Determine the Benefit Obligation	The weighted average assumptions used to determine the benefit obligation as of December 31 were: Pension Plans OPEB 2017 2016 2015 2017 2016 2015 Discount rate 3.85 % 4.40 % 4.65 % 3.65 % 4.10 % 4.25 % Rate of salaried compensation increase 3.00 % 3.00 % 3.00 % — — —
Schedule of Weighted Average Assumptions Used to Determine the Net Periodic Cost (Benefit)	The weighted average assumptions used to determine the net periodic cost (benefit) for the years ended December 31 were: Pension Plans OPEB 2017 2016 2015 2017 2016 2015 Discount rate 4.40 % 4.65 % 4.25 % 4.10 % 4.25 % 3.90 % Expected return on plan assets 6.50 % 6.50 % 6.75 % — — — Rate of salaried compensation increase 3.00 % 3.00 % 3.00 % — — —
Schedule of Effect of One-Percentage-Point Change in Assumed Health Care Cost Trend Rates	A one percentage point change in the health care cost trend rates would have the following effects on our December 31, 2017 Consolidated Financial Statements (Dollars in thousands) 1% Increase 1% Decrease Effect on total service cost plus interest cost $ 28 $ (24 ) Effect on accumulated postretirement benefit obligation $ 443 $ (373 )

Components of Accumulated Oth39

Components of Accumulated Other Comprehensive Loss (Tables)	12 Months Ended
	Dec. 31, 2017
Equity [Abstract]
Changes in Accumulated Other Comprehensive Loss	The following tables detail the changes in our accumulated other comprehensive loss (AOCL) on our Condensed Consolidated Balance Sheets (Dollars in thousands) Gains and losses on cash flow hedge Pension Plans OPEB Total Balance at January 1, 2017 $ (701 ) $ 120,627 $ (9,182 ) $ 110,744 Amounts arising during the period 145 (11,005 ) (350 ) (11,210 ) Amounts reclassified from AOCL (149 ) (9,011 ) 4,477 (4,683 ) Net change (4 ) (20,016 ) 4,127 (15,893 ) Balance at December 31, 2017 $ (705 ) $ 100,611 $ (5,055 ) $ 94,851 (Dollars in thousands) Gains and losses on cash flow hedge Pension Plans OPEB Total Balance at January 1, 2016 $ — $ 128,244 $ (13,741 ) $ 114,503 Amounts arising during the period (916 ) 2,666 191 1,941 Amounts reclassified from AOCL 215 (10,283 ) 4,368 (5,700 ) Net change (701 ) (7,617 ) 4,559 (3,759 ) Balance at December 31, 2016 $ (701 ) $ 120,627 $ (9,182 ) $ 110,744

Equity-Based Compensation Pla40

Equity-Based Compensation Plans (Tables)	12 Months Ended
	Dec. 31, 2017
Share Based Compensation [Abstract]
Details of Equity-Based Compensation Expense	The following table details our compensation expense and the related income tax benefit as of December 31: (Dollars in thousands) 2017 2016 2015 Employee equity-based compensation expense: Performance stock awards $ 3,582 $ 3,437 $ 3,877 Restricted stock units 1,140 953 881 Total employee equity-based compensation expense $ 4,722 $ 4,390 $ 4,758 Deferred compensation stock equivalent units expense $ 657 $ 732 $ 376 Total tax benefit recognized for shared-based payment awards $ 379 $ 317 $ 319
Fair Value of Performance Share Awards	The following table presents the key inputs used in calculating the fair value of the PSAs in 2017, 2016 and 2015, and the resulting fair values: 2017 2016 2015 Stock price as of valuation date $ 43.60 $ 25.92 $ 40.00 Risk-free rate 1.61 % 0.88 % 1.07 % Expected volatility 24.22 % 23.82 % 21.09 % Expected dividends 3.44 % 5.79 % 3.75 % Expected term (years) 3.00 3.00 3.00 Fair value of a performance share $ 53.85 $ 30.02 $ 36.71
Summary of Outstanding Performance Share Awards	The following table summarizes outstanding PSAs as of December 31, 2017, 2016 and 2015, and the changes during those years: 2017 2016 2015 (Dollars in thousands, except per share amounts) Shares Weighted Average Grant Date Fair Value Shares Weighted Average Grant Date Fair Value Shares Weighted Average Grant Date Fair Value Unvested shares outstanding at January 1 203,788 $ 32.59 161,049 $ 41.26 160,233 $ 53.86 Granted 78,033 $ 53.85 125,469 $ 30.02 78,974 $ 36.71 Vested (78,129 ) $ 36.71 (82,730 ) $ 45.57 (77,078 ) $ 62.78 Forfeited (3,061 ) $ 34.68 — $ — (1,080 ) $ 41.29 Unvested shares outstanding at December 31 200,631 $ 39.19 203,788 $ 32.59 161,049 $ 41.26 Total grant date fair value of share awards vested during the year $ 2,868 $ 3,770 $ 4,839 Aggregate intrinsic value of unvested share awards at December 31 $ 10,011 $ 8,488 $ 4,697
Summary of Outstanding RSU Awards	The following table summarizes outstanding RSU awards as of December 31, 2017, 2016 and 2015, and the changes during those years: 2017 2016 2015 (Dollars in thousands, except per share amounts) Shares Weighted Average Grant Date Fair Value Shares Weighted Average Grant Date Fair Value Shares Weighted Average Grant Date Fair Value Unvested shares outstanding at January 1 71,420 $ 31.61 44,531 $ 40.95 32,455 $ 42.24 Granted 26,507 $ 43.64 43,320 $ 26.08 27,820 $ 39.99 Vested (29,039 ) $ 39.65 (16,431 ) $ 39.92 (15,385 ) $ 44.50 Forfeited (1,017 ) $ 31.63 — $ — (359 ) $ 40.27 Unvested shares outstanding at December 31 67,871 $ 32.87 71,420 $ 31.61 44,531 $ 40.95 Total grant date fair value of RSU awards vested during the year $ 1,151 $ 656 $ 289 Aggregate intrinsic value of unvested RSU awards at December 31 $ 3,387 $ 2,975 $ 1,347

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Schedule of the Income Tax Provision Allocated to Continuing Operations	Income tax expense consists of the following for the years ended December 31: (Dollars in thousands) 2017 2016 2015 Current $ 16,657 $ (6,178 ) $ 128 Deferred 14,325 2,143 1,097 Net operating loss carryforwards 1,039 (290 ) (6,793 ) Income tax provision (benefit) $ 32,021 $ (4,325 ) $ (5,568 )
Schedule of Effective Income Tax Rate Reconciliation	Income tax expense differs from the amount computed by applying the statutory federal income tax rate of 35% to income before income taxes due to the following for the years ended December 31: (Dollars in thousands) 2017 2016 2015 U.S. federal statutory income tax $ 41,466 $ 2,314 $ 9,151 REIT income not subject to federal income tax (20,651 ) (7,199 ) (14,110 ) U.S. tax rate change on deferred tax assets and liabilities 10,528 — — Intercompany profit-in-inventory elimination adjustment — 1,465 — Change in valuation allowance 140 162 488 State income taxes, net of federal income tax 2,608 (740 ) (838 ) Domestic production activities deduction (1,511 ) (2 ) — Permanent book-tax differences (252 ) (218 ) (70 ) Research and development credits (294 ) (689 ) — All other items (13 ) 582 (189 ) Income tax provision (benefit) $ 32,021 $ (4,325 ) $ (5,568 ) Effective tax rate 27.0 % (65.4 %) (21.3 %)
Schedule of Deferred Tax Assets and Liabilities	The tax effects of significant temporary differences creating deferred tax assets and liabilities at December 31 were: (Dollars in thousands) 2017 2016 Deferred tax assets: Pensions $ 19,439 $ 37,423 Other postretirement employee benefits 7,891 13,002 Net operating loss carryforwards 54 983 Inventories 353 443 Tax credits 2,443 2,207 Nondeductible accruals 2,566 2,067 Incentive compensation 1,131 1,643 Employee benefits 1,037 1,444 Other 88 120 Total deferred tax assets 35,002 59,332 Valuation allowance (790 ) (650 ) Deferred tax assets, net of valuation allowance 34,212 58,682 Deferred tax liabilities: Timber and timberlands, net (1,432 ) (2,165 ) Property, plant and equipment, net (12,683 ) (14,018 ) Other (301 ) (448 ) Total deferred tax liabilities (14,416 ) (16,631 ) Deferred tax assets, net $ 19,796 $ 42,051
Summary of Tax Years Subject to Examination by Major Taxing Jurisdictions	The following table summarizes the tax years subject to examination by major taxing jurisdictions: Jurisdiction Years Federal 2013 — 2017 Arkansas 2014 — 2017 Michigan 2013 — 2017 Minnesota 2013 — 2017 Idaho 2014 — 2017
Summary of Reconciliation of Unrecognized Tax Benefits	A reconciliation of the beginning and ending unrecognized tax benefits is as follows: (Dollars in thousands) 2017 2016 Balance at January 1 $ 850 $ — Additions for tax positions of prior years 8 850 Reduction for tax positions of prior years (294 ) — Balance at December 31 $ 564 $ 850

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2017
Commitments And Contingencies Disclosure [Abstract]
Schedule of Future Minimum Rental Payments for Operating Leases	As of December 31, 2017, the future minimum rental payments required under our operating leases are as follows: (Dollars in thousands) 2018 $ 4,570 2019 3,518 2020 2,662 2021 1,771 2022 874 2023 and thereafter 992 Total $ 14,387

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2017
Segment Reporting Information Additional Information [Abstract]
Summary of Information by Business Segment	The following table presents business segment information for each of the past three years. Corporate information is included to reconcile segment data to the Consolidated Financial Statements (Dollars in thousands) 2017 2016 2015 Revenues: Resource $ 278,199 $ 256,163 $ 263,875 Wood Products 441,157 367,426 336,214 Real Estate 30,655 32,604 28,989 750,011 656,193 629,078 Intersegment Resource revenues 1 (71,416 ) (57,094 ) (53,742 ) Total consolidated revenues $ 678,595 $ 599,099 $ 575,336 Income (loss) before income taxes: Resource $ 106,105 $ 81,918 $ 76,350 Wood Products 72,166 24,587 (5,235 ) Real Estate 2 18,576 (29,495 ) 16,849 Eliminations and adjustments (2,705 ) (3,001 ) 3,283 194,142 74,009 91,247 Corporate (48,619 ) (38,455 ) (32,340 ) Operating income 145,523 35,554 58,907 Interest expense, net (27,049 ) (28,941 ) (32,761 ) Income before income taxes $ 118,474 $ 6,613 $ 26,146 Depreciation, depletion and amortization: Resource $ 20,476 $ 24,090 $ 28,807 Wood Products 7,347 7,357 6,810 Real Estate 2 4 56 27,825 31,451 35,673 Corporate 607 760 951 Bond discount and deferred loan fees 1,480 1,979 1,481 Total depreciation, depletion and amortization $ 29,912 $ 34,190 $ 38,105 Basis of real estate sold: Real Estate $ 7,114 $ 8,518 $ 7,394 Elimination and adjustments (287 ) (507 ) (382 ) Total basis of real estate sold $ 6,827 $ 8,011 $ 7,012 Assets: Resource and Real Estate 3 $ 670,240 $ 662,852 $ 837,630 Wood Products 154,479 150,855 131,103 824,719 813,707 968,733 Corporate 128,360 113,974 47,879 Total consolidated assets $ 953,079 $ 927,681 $ 1,016,612 Capital Expenditures: 4 Resource $ 15,120 $ 13,311 $ 13,497 Wood Products 10,723 5,491 18,482 Real Estate 87 111 184 25,930 18,913 32,163 Corporate 2,132 375 569 Total capital expenditures $ 28,062 $ 19,288 $ 32,732 1 2 3 Assets are shown on a combined basis for the Resource and Real Estate segments, as we do not report assets separately to management for these segments. 4 Excludes the acquisition of timber and timberlands.
Schedule of Revenue from External Customers Attributed to Foreign Countries by Geographic Area	All of our wood products facilities and all other assets are located within the continental United States. Geographic information regarding our revenues is as follows: (Dollars in thousands) 2017 2016 2015 United States $ 676,956 $ 597,899 $ 573,398 Canada 481 173 851 Mexico 1,158 1,027 919 Other — — 168 Total consolidated revenues $ 678,595 $ 599,099 $ 575,336

Financial Results by Quarter 44

Financial Results by Quarter (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Data [Abstract]
Schedule of Quarterly Financial Information	Three Months Ended March 31 June 30 September 30 December 31 (Dollars in thousands, except per share amounts) 2017 2016 2017 2016 2017 2016 2017 2016 Revenues $ 149,681 $ 127,896 $ 163,229 $ 141,495 $ 190,441 $ 174,027 $ 175,244 $ 155,681 Operating income (loss) $ 23,909 $ 5,072 $ 40,773 $ (34,228 ) $ 43,793 $ 38,994 $ 37,048 $ 25,716 Net income (loss) $ 16,921 $ 157 $ 24,244 $ (31,238 ) $ 33,700 $ 27,646 $ 11,588 $ 14,373 Net income (loss) per share 1 Basic $ 0.41 $ — $ 0.59 $ (0.77 ) $ 0.83 $ 0.68 $ 0.28 $ 0.35 Diluted $ 0.41 $ — $ 0.59 $ (0.77 ) $ 0.82 $ 0.68 $ 0.28 $ 0.35 1 Per share amounts are computed independently for each of the quarters presented. Therefore, the sum of the quarterly per share amounts may not equal the total computed for the year.

Summary of Significant Accoun45

Summary of Significant Accounting Policies (Narrative) (Details) $ in Thousands, a in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2018USD ($)	Dec. 31, 2017USD ($)a
Principle Accounting Policies [Line Items]
Timber And Timberlands Acres Owned | a		1.4
Operating Leases, Future Minimum Payments Due		$ 14,387
Scenario, Forecast [Member]
Principle Accounting Policies [Line Items]
Increase in accumulated other comprehensive loss due to change in comprehensive income reporting	$ 20,000
Pension and Other Postretirement Employee Benefit [Member]
Principle Accounting Policies [Line Items]
Net periodic pension and other postretirement employee benefit cost		13,200
Service cost		$ 6,800
Timber and Timberlands [Member] | Minimum [Member]
Principle Accounting Policies [Line Items]
Timber Volume Estimate, Review Period		5 years
Property, Plant and Equipment, Useful Life		5 years
Timber and Timberlands [Member] | Maximum [Member]
Principle Accounting Policies [Line Items]
Timber Volume Estimate, Review Period		10 years
Property, Plant and Equipment, Useful Life		20 years

Pending Merger With Deltic (Nar

Pending Merger With Deltic (Narrative) (Details) shares in Millions, $ in Millions	Oct. 22, 2017USD ($)ashares	Dec. 31, 2017
Business Acquisition [Line Items]
Date of merger agreement		Oct. 22, 2017
Deltic [Member]
Business Acquisition [Line Items]
Business acquisition, share price	180.00%
Acres of timberland | a	530,000
Estimated total consideration expected to be issued | shares	22
Merger termination fee, obligation payable	$ 66
Merger termination fee, obligation receivable	$ 33
Earnings and profits dividend rate or special distribution percentage of stock	80.00%
Earnings and profits dividend rate or special distribution percentage of cash	20.00%

Earnings per Share (Reconciliat

Earnings per Share (Reconciliation Of Number Of Common Shares Used In Calculating Basic And Diluted EPS) (Details) - USD ($) $ / shares in Units, $ in Thousands	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
Earnings per Share [Line Items]
Net income	$ 11,588		$ 33,700		$ 24,244		$ 16,921		$ 14,373		$ 27,646		$ (31,238)		$ 157		$ 86,453	$ 10,938	$ 31,714
Basic weighted-average shares outstanding																	40,824,420	40,797,806	40,842,126
Diluted weighted-average shares outstanding																	41,227,388	41,033,440	40,987,819
Basic net income per share	$ 0.28	[1]	$ 0.83	[1]	$ 0.59	[1]	$ 0.41	[1]	$ 0.35	[1]	$ 0.68	[1]	$ (0.77)	[1]	$ 0	[1]	$ 2.12	$ 0.27	$ 0.78
Diluted net income per share	$ 0.28	[1]	$ 0.82	[1]	$ 0.59	[1]	$ 0.41	[1]	$ 0.35	[1]	$ 0.68	[1]	$ (0.77)	[1]	$ 0	[1]	$ 2.10	$ 0.27	$ 0.77
Performance shares [Member]
Earnings per Share [Line Items]
Incremental shares																	362,509	200,164	122,334
Restricted stock units [Member]
Earnings per Share [Line Items]
Incremental shares																	40,459	35,470	23,359
[1]	Per share amounts are computed independently for each of the quarters presented. Therefore, the sum of the quarterly per share amounts may not equal the total computed for the year.

Earnings per Share (Narrative)

Earnings per Share (Narrative) (Details) - USD ($)	Apr. 26, 2016	Jun. 30, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Earnings per Share [Line Items]
Total anti-dilutive shares excluded from the calculation (in shares)			250	503	0
Stock repurchase program, period	24 months
Stock repurchase program, remaining authorized amount			$ 54,000,000
Maximum [Member]
Earnings per Share [Line Items]
Stock repurchase program, authorized amount	$ 60,000,000
Common Stock [Member]
Earnings per Share [Line Items]
Common stock repurchased and retired, shares		169,625
Common stock repurchased and retired, average price per share		$ 35.08
Common stock repurchased, shares			0	169,625

Inventories (Schedule of Invent

Inventories (Schedule of Inventories) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Inventory Disclosure [Abstract]
Logs	$ 20,133	$ 23,342
Lumber, plywood and veneer	20,889	20,500
Materials and supplies	9,110	8,780
Total inventories	50,132	52,622
Last-in, first-out basis	25,127	29,769
Average cost basis	$ 25,005	$ 22,853

Inventories (Narrative) (Detail

Inventories (Narrative) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Inventory Disclosure [Abstract]
Last-In, First-Out Reserve	$ 10.9	$ 11.1	$ 10.6

Property, Plant and Equipment51

Property, Plant and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Property Plant And Equipment [Line Items]
Land	$ 4,707	$ 4,712
Buildings and improvements	55,734	54,448
Machinery and equipment	197,648	190,316
Construction in progress	1,348	1,437
Property, Plant and Equipment, Gross	259,437	250,913
Less: accumulated depreciation	(182,208)	(178,093)
Total property, plant and equipment, net	$ 77,229	$ 72,820
Building and Improvements [Member] | Minimum [Member]
Property Plant And Equipment [Line Items]
Property, Plant and Equipment, Useful Life	10 years
Building and Improvements [Member] | Maximum [Member]
Property Plant And Equipment [Line Items]
Property, Plant and Equipment, Useful Life	40 years
Machinery and Equipment [Member] | Minimum [Member]
Property Plant And Equipment [Line Items]
Property, Plant and Equipment, Useful Life	2 years
Machinery and Equipment [Member] | Maximum [Member]
Property Plant And Equipment [Line Items]
Property, Plant and Equipment, Useful Life	25 years

Property, Plant and Equipment52

Property, Plant and Equipment (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property Plant And Equipment [Abstract]
Depreciation	$ 8.1	$ 8.3	$ 8.2
Interest expense capitalized			$ 0.2

Timber and Timberlands (Schedul

Timber and Timberlands (Schedule of Timber and Timberlands) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Timber And Timberlands [Abstract]
Timber and timberlands	$ 581,648	$ 572,273
Logging roads	72,828	69,583
Total timber and timberlands, net	$ 654,476	$ 641,856

Timber and Timberlands (Narrati

Timber and Timberlands (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Timber And Timberlands [Abstract]
Depletion from Company Owned Lands	$ 17	$ 20.8	$ 25.3
Amortization of Logging Roads	$ 3.2	$ 3.1	$ 3.1

Timber and Timberlands (Sched55

Timber and Timberlands (Schedule of Future Payments Due Under Timber Cutting Contracts) (Details) $ in Thousands	Dec. 31, 2017USD ($)
Timber And Timberlands [Abstract]
2,018	$ 11,280
2,019	2,730
2,020	1,085
2,021	5,370
2,022	281
Total	$ 20,746

Other Current Assets (Details)

Other Current Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Other Assets [Abstract]
Real estate held for sale	$ 7,721	$ 9,184
Prepaid expenses	2,862	1,939
Other receivables	882	2,442
Interest rate swaps	13	32
Total other current assets	$ 11,478	$ 13,597

Accounts Payable and Accrued 57

Accounts Payable and Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Accounts Payable And Accrued Liabilities Current [Abstract]
Accrued payroll and benefits	$ 18,110	$ 13,634
Accounts payable	9,361	8,382
Accrued interest	6,385	6,237
Avery Landing accrual	6,000	1,022
Accrued taxes	5,103	4,956
Other current liabilities	10,242	9,479
Total accounts payable and accrued liabilities	$ 55,201	$ 43,710

Debt (Schedule of Long-Term Deb

Debt (Schedule of Long-Term Debt) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Long-term principal	$ 576,485	$ 587,485
Debt issuance costs	(2,321)	(3,015)
Unamortized discounts	(472)	(729)
Total long-term debt (includes current portion)	573,319	583,988
Less current portion of long-term debt	(14,263)	(11,032)
Long-term debt	559,056	572,956
Interest Rate Swaps [Member]
Debt Instrument [Line Items]
Debt instrument	(373)	247
Term Loans [Member]
Debt Instrument [Line Items]
Long-term principal	343,500	349,500
Senior Notes [Member]
Debt Instrument [Line Items]
Long-term principal	150,000	150,000
Revenue Bonds [Member]
Debt Instrument [Line Items]
Long-term principal	65,735	65,735
Medium Term Notes [Member]
Debt Instrument [Line Items]
Long-term principal	$ 17,250	$ 22,250

Debt (Narrative) (Details)

Debt (Narrative) (Details)	12 Months Ended
	Dec. 31, 2017USD ($)Tranche	Dec. 31, 2016USD ($)	Dec. 31, 2009USD ($)	Feb. 14, 2018USD ($)	Dec. 31, 2014USD ($)
Debt Instrument [Line Items]
Number of Tranches Included in Term Loan | Tranche	8
Long-term Debt, Maturities, Repayments of Principal in Year Three	$ 46,000,000
Long-term Debt, Maturities, Repayments of Principal in Year Two	190,000,000
Long-term Debt, Maturities, Repayment of Principal in Year Four	40,000,000
Long-term Debt, Maturities, Repayment of Principal in Year Five	$ 43,000,000
Debt instrument maturity date, description	due 2018 through 2022
Amount Available to Increase Borrowing Capacity					$ 250,000,000
Revolving line of credit borrowings	$ 0
Remaining Borrowing Capacity	$ 249,100,000
Scenario, Forecast [Member]
Debt Instrument [Line Items]
Amount Available to Increase Borrowing Capacity				$ 420,000,000
Line of Credit [Member]
Debt Instrument [Line Items]
Maximum Borrowing Capacity					250,000,000
Additional Applicable Rate Added to Base Rate, Minimum		1.50%
Additional Applicable Rate Added to Base Rate, At End of Period		0.50%
Unused Capacity, Commitment Fee Percentage	0.25%
Line of Credit [Member] | Scenario, Forecast [Member]
Debt Instrument [Line Items]
Maximum Borrowing Capacity				380,000,000
Letter of Credit [Member]
Debt Instrument [Line Items]
Maximum Borrowing Capacity					40,000,000
Line of Credit Facility, Amount Outstanding	$ 900,000
Letter of Credit [Member] | Scenario, Forecast [Member]
Debt Instrument [Line Items]
Maximum Borrowing Capacity				75,000,000
Swing Line Loan [Member]
Debt Instrument [Line Items]
Maximum Borrowing Capacity					$ 25,000,000
Swing Line Loan [Member] | Scenario, Forecast [Member]
Debt Instrument [Line Items]
Maximum Borrowing Capacity				$ 25,000,000
Revenue Bonds [Member]
Debt Instrument [Line Items]
Interest Rate		2.75%
Long-term Debt, refinancing amount		$ 65,700
Term Loans [Member]
Debt Instrument [Line Items]
Repayments of debt	6,000,000
Senior Notes [Member]
Debt Instrument [Line Items]
Interest Rate			7.50%
Proceeds from Issuance of Debt			$ 150,000,000
Medium Term Notes [Member]
Debt Instrument [Line Items]
Repayments of debt	$ 5,000,000
Minimum [Member] | Medium Term Notes [Member]
Debt Instrument [Line Items]
Interest Rate	8.75%
Maximum [Member] | Medium Term Notes [Member]
Debt Instrument [Line Items]
Interest Rate	8.89%
London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.00%
Federal Fund Rate [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.50%
Eurodollar [Member] | Minimum [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.875%
Eurodollar [Member] | Maximum [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.70%
Base Rate [Member] | Minimum [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.00%
Base Rate [Member] | Maximum [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.70%
Term Loan, Tranche One [Member]
Debt Instrument [Line Items]
Number of Tranches Included in Term Loan | Tranche	1
Term Loan, Tranche One [Member] | Term Loans [Member]
Debt Instrument [Line Items]
Long-term Debt, Maturities, Repayments of Principal in Year Three	$ 6,000,000
Term Loan, Tranche One [Member] | Debt Instrument, Redemption, Period Two [Member] | Term Loans [Member]
Debt Instrument [Line Items]
Interest Rate	3.70%
Term Loan, Tranche Two [Member] | Term Loans [Member]
Debt Instrument [Line Items]
Number of Tranches Included in Term Loan | Tranche	3
Long-term Debt, Maturities, Repayments of Principal in Year Three	$ 40,000,000
Long-term Debt, Maturities, Repayments of Principal in Year Two	40,000,000
Long-term Debt, Maturities, Repayment of Principal in Year Four	$ 40,000,000
Term Loan, Tranche Two [Member] | LIBOR [Member] | Minimum [Member] | Term Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.65%
Term Loan, Tranche Two [Member] | LIBOR [Member] | Maximum [Member] | Term Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.90%
Term Loan, Tranche Three [Member] | Term Loans [Member]
Debt Instrument [Line Items]
Number of Tranches Included in Term Loan | Tranche	2
Long-term Debt, Maturities, Repayment of Principal in Year Five	$ 40,000,000
Long-term Debt, Maturities, Repayment of Principal in Year Six	$ 40,000,000
Term Loan, Tranche Three [Member] | Debt Instrument, Redemption, Period Two [Member] | Term Loans [Member]
Debt Instrument [Line Items]
Interest Rate	4.49%
Term Loan, Tranche Three [Member] | Debt Instrument, Redemption, Period One | Term Loans [Member]
Debt Instrument [Line Items]
Interest Rate	4.29%
Term Loan, Tranche Four [Member] | Term Loans [Member]
Debt Instrument [Line Items]
Number of Tranches Included in Term Loan | Tranche	1
Long-term Debt, Maturities, Repayment of Principal in Year Seven	$ 110,000,000
Term Loan, Tranche Four [Member] | Debt Instrument, Redemption, Period One | Term Loans [Member]
Debt Instrument [Line Items]
Interest Rate	4.64%
Term Loan, Tranche Five [Member]
Debt Instrument [Line Items]
Number of Tranches Included in Term Loan | Tranche	1
Long-term Debt, Maturities, Repayment of Principal in Year Nine	$ 27,500,000
Term Loan, Tranche Five [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Interest Rate	2.15%
2026 Maturity [Member] | Revenue Bonds [Member]
Debt Instrument [Line Items]
Repayments of debt		$ 42,600,000
Interest Rate		5.90%
Debt instrument maturity date		2,026
2024 Maturity [Member] | Revenue Bonds [Member]
Debt Instrument [Line Items]
Interest Rate		6.00%
Debt instrument maturity date		2,024

Debt (Scheduled Payments Due on

Debt (Scheduled Payments Due on Long-Term Debt) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Long Term Debt By Maturity [Abstract]
2,018	$ 14,250
2,019	190,000
2,020	46,000
2,021	40,000
2,022	43,000
Thereafter	243,235
Debt Instrument, Face Amount	$ 576,485	$ 587,485

Derivative Instruments (Narrati

Derivative Instruments (Narrative) (Details) $ in Millions	1 Months Ended		12 Months Ended
	Dec. 31, 2017USD ($)Derivative	Apr. 30, 2017USD ($)MMcf	Dec. 31, 2017USD ($)Derivative
Interest Rate Swaps [Member]
Derivatives, Fair Value [Line Items]
Number of interest rate swap agreements | Derivative	3		3
Notional amounts	$ 14.3		$ 14.3
LIBOR variable interest rate	6.17%		6.17%
Derivative, termination term			Fair value swaps terminate at various dates in the first quarter of 2018
Senior Notes	$ 50		$ 50
Derivative original maturity date			Nov. 30, 2019
Interest expense over the next twelve months			$ 0.2
Interest Rate Swaps [Member] | Cash Flow Hedging [Member]
Derivatives, Fair Value [Line Items]
Number of interest rate swap agreements | Derivative	1		1
Notional amounts	$ 27.5		$ 27.5
Swaps fixed interest rate	3.88%		3.88%
LIBOR variable interest rate	2.15%		2.15%
Interest Rate Swaps [Member] | Senior notes [Member]
Derivatives, Fair Value [Line Items]
Derivative, termination year			2017-12
Termination cost	$ 0.4
Interest Rate Swaps [Member] | Term Loans [Member] | Cash Flow Hedging [Member]
Derivatives, Fair Value [Line Items]
Derivative, termination year			2026-02
Term loan debt	$ 27.5		$ 27.5
Interest Rate Swaps [Member] | Minimum [Member]
Derivatives, Fair Value [Line Items]
Swaps fixed interest rate	8.88%		8.88%
Interest Rate Swaps [Member] | Maximum [Member]
Derivatives, Fair Value [Line Items]
Swaps fixed interest rate	8.89%		8.89%
Commodity Contract [Member] | Swap [Member] | Derivatives not designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Volume of southern yellow pine in lumber price swap | MMcf		3
Lumber price swap expiration date		Dec. 31, 2017
Realized gain on lumber price swap		$ 1.1

Derivative Instruments (Fair Va

Derivative Instruments (Fair Value of Cash Flow and Fair Value Derivative Instruments) (Details) - Designated as Hedging Instrument [Member] - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Fair Value Hedging [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives, Fair Value	$ 13	$ 247
Liability Derivatives, Fair Value		91
Fair Value Hedging [Member] | Interest rate contracts [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives, Fair Value	13	32
Fair Value Hedging [Member] | Interest rate contracts [Member] | Other Noncurrent Assets [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives, Fair Value		215
Liability Derivatives, Fair Value		91
Cash Flow Hedging [Member] | Interest rate contracts [Member] | Other Noncurrent Assets [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives, Fair Value	$ 1,156	$ 1,148

Derivative Instruments (Effect

Derivative Instruments (Effect of Derivatives on Consolidated Statements of Income) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Designated as Hedging Instrument [Member] | Fair Value Hedging [Member] | Interest rate contracts [Member] | Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Realized gain on interest rate contracts	[1]	$ 413	$ 805	$ 1,534
Designated as Hedging Instrument [Member] | Cash Flow Hedging [Member] | Interest rate contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized in other comprehensive income, net of tax (effective portion)		(145)	916
Designated as Hedging Instrument [Member] | Cash Flow Hedging [Member] | Interest rate contracts [Member] | Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Loss reclassified from accumulated other comprehensive income (effective portion)	[1]	(149)	$ (215)
Derivatives not designated as Hedging Instrument [Member] | Lumber price contracts [Member] | Gain on Lumber Hedge [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Realized gain on lumber price swap		$ 1,088
[1]	Realized gains and losses on interest rate contracts consist of net cash received or paid and interest accruals on the interest rate swaps during the periods. Net cash received or paid is included in the supplemental cash flow information within interest, net of amounts capitalized in the Consolidated Statements of Cash Flows

Financial Instruments (Estimate

Financial Instruments (Estimated Fair Values of Financial Instruments) (Details) - USD ($) $ in Thousands		Dec. 31, 2017	Dec. 31, 2016
Carrying Amount [Member] | Level 1 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash and cash equivalents		$ 120,457	$ 82,584
Carrying Amount [Member] | Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Long-term debt, including current portion	[1]	(576,013)	(586,756)
Carrying Amount [Member] | Level 2 [Member] | Interest rate contracts [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative assets		1,169	1,395
Derivative liabilities related to interest rate swaps			(91)
Carrying Amount [Member] | Level 2 [Member] | Term Loans [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Long-term debt, including current portion		(343,500)	(349,500)
Carrying Amount [Member] | Level 2 [Member] | Senior notes [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Long-term debt, including current portion		(149,528)	(149,271)
Carrying Amount [Member] | Level 2 [Member] | Revenue bonds [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Long-term debt, including current portion		(65,735)	(65,735)
Carrying Amount [Member] | Level 2 [Member] | Medium-term notes [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Long-term debt, including current portion		(17,250)	(22,250)
Carrying Amount [Member] | Level 3 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Company owned life insurance (COLI)		1,996	70
Fair Value [Member] | Level 1 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash and cash equivalents		120,457	82,584
Fair Value [Member] | Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Long-term debt, including current portion	[1]	(588,479)	(601,290)
Fair Value [Member] | Level 2 [Member] | Interest rate contracts [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative assets		1,169	1,395
Derivative liabilities related to interest rate swaps			(91)
Fair Value [Member] | Level 2 [Member] | Term Loans [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Long-term debt, including current portion		(345,222)	(350,909)
Fair Value [Member] | Level 2 [Member] | Senior notes [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Long-term debt, including current portion		(161,063)	(164,250)
Fair Value [Member] | Level 2 [Member] | Revenue bonds [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Long-term debt, including current portion		(63,967)	(62,205)
Fair Value [Member] | Level 2 [Member] | Medium-term notes [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Long-term debt, including current portion		(18,227)	(23,926)
Fair Value [Member] | Level 3 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Company owned life insurance (COLI)		$ 1,996	$ 70
[1]	The carrying amount of long-term debt includes principal and unamortized discounts.

Savings Plans, Pension Plans 65

Savings Plans, Pension Plans and Other Postretirement Employee Benefits (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2009
Defined Benefit Plan Disclosure [Line Items]
401(K) contributions by employer	$ 2,400,000	$ 2,100,000	$ 2,100,000
Accumulated benefit obligation	$ 389,600,000	379,500,000
Expected return on plan assets	6.25%
Expected increase in net periodic cost due to 25 basis point decrease in pension discount rate	$ 700,000
Expected increase in projected benefit obligation due to 25 basis point decrease in pension discount rate	10,300,000
Expected increase in net periodic cost due to 25 basis point decrease in the assumption for expected return on plan assets	$ 700,000
Health care cost trend rate assumed for next fiscal year	8.38%
Defined Benefit Plan, Assumption Health Care Cost Trend Rate for Next Fiscal Year	4.50%
Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Investments in Level 3	$ 0	$ 0
Accumulated Other Comprehensive Loss [Member]
Defined Benefit Plan Disclosure [Line Items]
Decrease in accumulated postretirement benefit obligations				$ 76,700,000
Management Deferred Compensation Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Annual incentive plan, employee permitted minimum defer percentage	50.00%
Annual incentive plan, employee permitted maximum defer percentage	100.00%
Management Deferred Compensation Plan [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Basic salary defer percentage	50.00%
Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Estimated net loss to be amortized from Accumulated Other Comprehensive Loss into Net Periodic Benefit Cost	$ 16,600,000
Estimated prior service cost to be amortized from Accumulated Other Comprehensive Loss into Net Periodic Benefit Cost	200,000
Non-qualified pension plan and other postretirement employee benefit, estimated payments in next fiscal year	$ 28,536,000
Expected return on plan assets	6.50%	6.50%	6.75%
Pension Plans [Member] | Qualified Plan [member]
Defined Benefit Plan Disclosure [Line Items]
Estimated contributions in next fiscal year	$ 10,100,000
Pension Plans [Member] | Nonqualified Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Non-qualified pension plan and other postretirement employee benefit, estimated payments in next fiscal year	5,300,000
Other Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Estimated net loss to be amortized from Accumulated Other Comprehensive Loss into Net Periodic Benefit Cost	1,400,000
Estimated prior service cost to be amortized from Accumulated Other Comprehensive Loss into Net Periodic Benefit Cost	8,900,000
Non-qualified pension plan and other postretirement employee benefit, estimated payments in next fiscal year	3,704,000
Other Postretirement Benefit Plans [Member] | Nonqualified Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Non-qualified pension plan and other postretirement employee benefit, estimated payments in next fiscal year	$ 5,300,000

Savings Plans, Pension Plans 66

Savings Plans, Pension Plans and Other Postretirement Employee Benefits (Change in Benefit Obligation, Plan Assets and Funded Status for Company-Sponsored Benefit Plans and Obligations) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	$ 289,675
Fair value of plan assets at end of year	313,862	$ 289,675
Amounts recognized in the consolidated balance sheets [Abstract]
Noncurrent liabilities	(103,524)	(123,284)
Pension Plans [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at beginning of year	(385,461)	(382,071)
Service cost	(6,753)	(6,508)	$ (6,159)
Interest cost	(16,096)	(17,020)	(17,012)
Actuarial (loss) gain	(15,876)	(13,997)
Benefits paid	31,815	34,135
Benefit obligation at end of year	(392,371)	(385,461)	(382,071)
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	289,675	292,200
Actual return on plan assets	49,158	28,626
Employer contributions and benefit payments	6,844	2,984
Benefits paid	(31,815)	(34,135)
Fair value of plan assets at end of year	313,862	289,675	292,200
Amounts recognized in the consolidated balance sheets [Abstract]
Current liabilities	(1,629)	(1,824)
Noncurrent liabilities	(76,880)	(93,962)
Funded status	(78,509)	(95,786)
OPEB [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at beginning of year	(33,337)	(35,471)
Service cost	(14)	(14)	(22)
Interest cost	(1,262)	(1,421)	(1,456)
Actuarial (loss) gain	471	(313)
Benefits paid	3,793	3,882
Benefit obligation at end of year	(30,349)	(33,337)	$ (35,471)
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Employer contributions and benefit payments	3,794	3,882
Benefits paid	(3,794)	(3,882)
Amounts recognized in the consolidated balance sheets [Abstract]
Current liabilities	(3,705)	(4,015)
Noncurrent liabilities	(26,644)	(29,322)
Funded status	$ (30,349)	$ (33,337)

Savings Plans, Pension Plans 67

Savings Plans, Pension Plans and Other Postretirement Employee Benefits (Long-Term Asset Allocation Ranges) (Details)	12 Months Ended
	Dec. 31, 2017
Minimum [Member]
Domestic and international equities	24.00%
Fixed income securities	38.00%
Alternatives, which may include equities and fixed income securities	12.00%
Cash and cash equivalents	0.00%
Maximum [Member]
Domestic and international equities	48.00%
Fixed income securities	58.00%
Alternatives, which may include equities and fixed income securities	18.00%
Cash and cash equivalents	5.00%

Savings Plans, Pension Plans 68

Savings Plans, Pension Plans and Other Postretirement Employee Benefits (Actual Plan Asset Allocations of the Pension Benefit Plans' Assets) (Details) - Pension Plans [Member]	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan, Actual Plan Asset Allocations	100.00%	100.00%
Domestic Equity Securities [Member]
Defined Benefit Plan, Actual Plan Asset Allocations	37.00%	36.00%
Fixed income [Member]
Defined Benefit Plan, Actual Plan Asset Allocations	47.00%	48.00%
Other notes [Member]
Defined Benefit Plan, Actual Plan Asset Allocations	16.00%	16.00%

Savings Plans, Pension Plans 69

Savings Plans, Pension Plans and Other Postretirement Employee Benefits (Fair Value Measurements) (Details) - USD ($) $ in Thousands		Dec. 31, 2017	Dec. 31, 2016
Fair Value of Plan Assets		$ 313,862	$ 289,675
Cash and Cash Equivalents [Member]
Fair Value of Plan Assets		3,004	2,845
Domestic Equity Securities [Member]
Fair Value of Plan Assets	[1]	57,560	51,688
International Equity Securities [Member]
Fair Value of Plan Assets	[2]	28,413	26,555
Emerging Markets [Member]
Fair Value of Plan Assets	[3]	29,257	26,403
Fixed Income Securities [Member]
Fair Value of Plan Assets	[4]	148,833	138,897
Alternative Securities [Member]
Fair Value of Plan Assets	[5]	46,795	43,287
Level 1 [Member]
Fair Value of Plan Assets		181,027	167,163
Level 1 [Member] | Cash and Cash Equivalents [Member]
Fair Value of Plan Assets		3,004	2,845
Level 1 [Member] | Domestic Equity Securities [Member]
Fair Value of Plan Assets	[1]	29,178	25,409
Level 1 [Member] | Emerging Markets [Member]
Fair Value of Plan Assets	[3]	12	12
Level 1 [Member] | Fixed Income Securities [Member]
Fair Value of Plan Assets	[4]	148,833	138,897
Level 2 [Member]
Fair Value of Plan Assets		132,835	122,512
Level 2 [Member] | Domestic Equity Securities [Member]
Fair Value of Plan Assets	[1]	28,382	26,279
Level 2 [Member] | International Equity Securities [Member]
Fair Value of Plan Assets	[2]	28,413	26,555
Level 2 [Member] | Emerging Markets [Member]
Fair Value of Plan Assets	[3]	29,245	26,391
Level 2 [Member] | Alternative Securities [Member]
Fair Value of Plan Assets	[5]	$ 46,795	$ 43,287
[1]	Level 1 assets are managed investments in U.S. small/mid-cap equities that track the Russell 2500 Growth index or Russell 2500 Value index. Level 2 assets are collective investments, which are invested in U.S. large-cap equities that track the S&P 500.
[2]	Level 2 assets are collective investments in equity funds of developed markets outside of the United States and Canada that track the MSCI EAFE Value index or MSCI EAFE Growth index
[3]	Level 1 assets are mutual funds which are invested in the common stock of companies located (or with primary operations) in emerging markets that track the MSCI Emerging Markets index. Level 2 assets are collective investments in the common stock of companies located (or with primary operations) in emerging markets that track the MSCI Emerging Markets index.
[4]	Level 1 assets are mutual funds and investments in a diversified portfolio of fixed income instruments of varying maturities representing corporates, sovereign debt, U.S. treasuries and municipals that track the Barclay's Long-term Credit index.
[5]	Level 2 assets are collective investments in inflation-indexed bonds, securities of real estate companies, commodity index-linked notes, fixed income securities, foreign currencies, securities of natural resource companies, master limited partnerships, publicly listed infrastructure companies, floating-rate debt, securities of global agriculture companies and securities of global timber companies.

Savings Plans, Pension Plans 70

Savings Plans, Pension Plans and Other Postretirement Employee Benefits (Pre-Tax Components Of Net Periodic Cost (Benefit)) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 6,753	$ 6,508	$ 6,159
Interest cost	16,096	17,020	17,012
Expected return on plan assets	(18,406)	(18,999)	(20,804)
Amortization of prior service cost (credit)	288	518	605
Amortization of actuarial loss	14,484	16,339	17,937
Net periodic cost (benefit)	19,215	21,386	20,909
OPEB [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	14	14	22
Interest cost	1,262	1,421	1,456
Amortization of prior service cost (credit)	(8,877)	(8,877)	(9,312)
Amortization of actuarial loss	1,537	1,717	2,047
Net periodic cost (benefit)	$ (6,064)	$ (5,725)	$ (5,787)

Savings Plans, Pension Plans 71

Savings Plans, Pension Plans and Other Postretirement Employee Benefits (Other Amounts Recognized in Consolidated Statements of Comprehensive Income) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Net amount at beginning of year	$ (110,744)
Taxes	(3,990)	$ 1,826	$ 1,913
Net amount arising during the period	11,355	(2,857)	(2,990)
Net reclassifications during the period	(15,889)	(3,058)	(3,889)
Net amount at end of year	(94,851)	(110,744)
Pension Plans [Member]
Net amount at beginning of year	120,627	128,244	134,261
Net (gain) loss	(14,874)	4,370	8,680
Taxes	3,869	(1,704)	(3,386)
Net amount arising during the period	(11,005)	2,666	5,294
Amortization of prior service (cost) credit	(288)	(518)	(605)
Amortization of actuarial loss	(14,484)	(16,339)	(17,937)
Taxes	5,761	6,574	7,231
Net reclassifications during the period	(9,011)	(10,283)	(11,311)
Net amount at end of year	100,611	120,627	128,244
OPEB [Member]
Net amount at beginning of year	(9,182)	(13,741)	(15,869)
Net (gain) loss	(471)	313	(3,777)
Taxes	121	(122)	1,473
Net amount arising during the period	(350)	191	(2,304)
Amortization of prior service (cost) credit	8,877	8,877	9,312
Amortization of actuarial loss	(1,537)	(1,717)	(2,047)
Taxes	(2,863)	(2,792)	(2,833)
Net reclassifications during the period	4,477	4,368	4,432
Net amount at end of year	$ (5,055)	$ (9,182)	$ (13,741)

Savings Plans, Pension Plans 72

Savings Plans, Pension Plans and Other Postretirement Employee Benefits (Amounts Recognized in AOCI on Consolidated Balance Sheet) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Pension Plans [Member]
Net loss	$ 100,070	$ 120,006
Prior service cost (credit)	541	621
Net amount recognized	100,611	120,627
OPEB [Member]
Net loss	10,165	8,778
Prior service cost (credit)	(15,220)	(17,960)
Net amount recognized	$ (5,055)	$ (9,182)

Savings Plans, Pension Plans 73

Savings Plans, Pension Plans and Other Postretirement Employee Benefits (Schedule of Estimated Future Benefit Payments) (Details) $ in Thousands	Dec. 31, 2017USD ($)
Pension Plans [Member]
2,018	$ 28,536
2,019	28,264
2,020	27,951
2,021	27,588
2,022	27,255
2022–2026	128,115
OPEB [Member]
2,018	3,704
2,019	3,454
2,020	3,231
2,021	2,944
2,022	2,760
2022–2026	$ 10,557

Savings Plans, Pension Plans 74

Savings Plans, Pension Plans and Other Postretirement Employee Benefits (Weighted Average Assumptions Used to Determine the Benefit Obligation) (Details)	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Pension Plans [Member]
Discount rate	3.85%	4.40%	4.65%
Rate of salaried compensation increase	3.00%	3.00%	3.00%
OPEB [Member]
Discount rate	3.65%	4.10%	4.25%

Savings Plans, Pension Plans 75

Savings Plans, Pension Plans and Other Postretirement Employee Benefits (Weighted Average Assumptions used to Determine the Net Periodic Cost (Benefit)) (Details)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Expected return on plan assets	6.25%
Pension Plans [Member]
Discount rate	4.40%	4.65%	4.25%
Expected return on plan assets	6.50%	6.50%	6.75%
Rate of salaried compensation increase	3.00%	3.00%	3.00%
OPEB [Member]
Discount rate	4.10%	4.25%	3.90%

Savings Plans, Pension Plans 76

Savings Plans, Pension Plans and Other Postretirement Employee Benefits (One Percent Point Change in Health Care Cost Trend Rate Effect) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)
Savings Plans Pension Plans And Other Postretirement Employee Benefits [Abstract]
Effect on total service and interest cost components, 1% increase	$ 28
Effect on total service and interest cost components, 1% decrease	(24)
Effect on accumulated postretirement benefit obligation, 1% increase	443
Effect on accumulated postretirement benefit obligation, 1% decrease	$ (373)

Components of Accumulated Oth77

Components of Accumulated Other Comprehensive Loss (Changes in Accumulated Other Comprehensive Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accumulated Other Comprehensive Income Loss [Line Items]
Balance at beginning of period	$ (156,274)	$ (203,736)	$ (225,066)
Amounts arising during the period	(11,210)	1,941
Amounts reclassified from AOCL	(4,683)	(5,700)
Net change	(15,893)	(3,759)	(3,889)
Balance at end of period	(200,542)	(156,274)	(203,736)
Gains and losses on cash flow hedge [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Balance at beginning of period	(701)
Amounts arising during the period	145	(916)
Amounts reclassified from AOCL	(149)	215
Net change	(4)	(701)
Balance at end of period	(705)	(701)
Pension and other postretirement employee benefits [Member] | Pension Plans [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Balance at beginning of period	120,627	128,244
Amounts arising during the period	(11,005)	2,666
Amounts reclassified from AOCL	(9,011)	(10,283)
Net change	(20,016)	(7,617)
Balance at end of period	100,611	120,627	128,244
Pension and other postretirement employee benefits [Member] | OPEB [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Balance at beginning of period	(9,182)	(13,741)
Amounts arising during the period	(350)	191
Amounts reclassified from AOCL	4,477	4,368
Net change	4,127	4,559
Balance at end of period	(5,055)	(9,182)	(13,741)
Accumulated Other Comprehensive Loss [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Balance at beginning of period	110,744	114,503	118,392
Balance at end of period	$ 94,851	$ 110,744	$ 114,503

Equity-Based Compensation Pla78

Equity-Based Compensation Plans (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017USD ($)shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted Stock Unit, Vested, Issuance Deferred	74,067
Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, shares reserved for future issuance	141,938
Performance shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance share award granted under stock incentive plan, performance period	3 years
Unrecognized compensation cost | $	$ 4
Weighted average period (in years)	1 year 4 months 24 days
Restricted stock units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost | $	$ 1.1
Weighted average period (in years)	1 year 4 months 24 days
Minimum [Member] | Performance shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares Actually Issued, as a Percent of the Amount Subject to the Performance Share Award	0.00%
Minimum [Member] | Restricted stock units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting Period	1 year
Maximum [Member] | Performance shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares Actually Issued, as a Percent of the Amount Subject to the Performance Share Award	200.00%
Maximum [Member] | Restricted stock units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting Period	3 years
2005 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized	1,600,000
2014 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized	1,000,000
2005 and 2014 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized	400,000

Equity-Based Compensation Pla79

Equity-Based Compensation Plans (Details Of Equity-Based Compensation Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee equity-based compensation expense	$ 4,722	$ 4,390	$ 4,758
Deferred compensation stock equivalent units expense	657	732	376
Total tax benefit recognized for shared-based payment awards	379	317	319
Performance stock awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee equity-based compensation expense	3,582	3,437	3,877
Restricted stock units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee equity-based compensation expense	$ 1,140	$ 953	$ 881

Equity-Based Compensation Pla80

Equity-Based Compensation Plans (Fair Value of Performance Share Awards) (Details) - Performance shares [Member] - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock price as of valuation date (in dollars per share)	$ 43.60	$ 25.92	$ 40
Risk-free rate	1.61%	0.88%	1.07%
Expected volatility	24.22%	23.82%	21.09%
Expected dividends	3.44%	5.79%	3.75%
Expected term (years)	3 years	3 years	3 years
Fair value of a performance share	$ 53.85	$ 30.02	$ 36.71

Equity-Based Compensation Pla81

Equity-Based Compensation Plans (Summary Of Outstanding Performance Shares/Restricted Stock Units) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Performance shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Unvested shares outstanding at January 1, Shares	203,788	161,049	160,233
Granted (in shares)	78,033	125,469	78,974
Vested (in shares)	(78,129)	(82,730)	(77,078)
Forfeited (in shares)	(3,061)		(1,080)
Unvested shares outstanding at December 31, Shares	200,631	203,788	161,049
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Total Fair Value	$ 2,868	$ 3,770	$ 4,839
Aggregate Intrinsic Value	$ 10,011	$ 8,488	$ 4,697
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Unvested shares outstanding at January 1, Weighted Average Grant Date Fair Value (in dollars per share)	$ 32.59	$ 41.26	$ 53.86
Granted, Weighted Average Exercise Price (in dollars per share)	53.85	30.02	36.71
Vested, Weighted Average Grant Date Fair Value (in dollars per share)	36.71	45.57	62.78
Forfeited, Weighted Average Grant Date Fair Value (in dollars per share)	34.68		41.29
Unvested shares outstanding at December 31, Weighted Average Grant Date Fair Value (in dollars per share)	$ 39.19	$ 32.59	$ 41.26
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Unvested shares outstanding at January 1, Shares	71,420	44,531	32,455
Granted (in shares)	26,507	43,320	27,820
Vested (in shares)	(29,039)	(16,431)	(15,385)
Forfeited (in shares)	(1,017)		(359)
Unvested shares outstanding at December 31, Shares	67,871	71,420	44,531
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Total Fair Value	$ 1,151	$ 656	$ 289
Aggregate Intrinsic Value	$ 3,387	$ 2,975	$ 1,347
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Unvested shares outstanding at January 1, Weighted Average Grant Date Fair Value (in dollars per share)	$ 31.61	$ 40.95	$ 42.24
Granted, Weighted Average Exercise Price (in dollars per share)	43.64	26.08	39.99
Vested, Weighted Average Grant Date Fair Value (in dollars per share)	39.65	39.92	44.50
Forfeited, Weighted Average Grant Date Fair Value (in dollars per share)	31.63		40.27
Unvested shares outstanding at December 31, Weighted Average Grant Date Fair Value (in dollars per share)	$ 32.87	$ 31.61	$ 40.95

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details) - USD ($)	Jan. 01, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Taxes [Line Items]
Statutory Federal Income Tax Rate		35.00%
Reduction in net deferred tax assets including valuation allowance		$ 10,700,000
Valuation allowance		790,000	$ 650,000	$ 500,000
Change in Valuation Allowance		100,000
Unrecognized tax benefits		564,000	$ 850,000	$ 0
Idaho [Member]
Income Taxes [Line Items]
Investment Tax Credits		$ 3,100,000
Earliest Tax Year [Member] | Idaho [Member]
Income Taxes [Line Items]
Idaho Investment Tax Credits expiration year		2,019
Latest Tax Year [Member] | Idaho [Member]
Income Taxes [Line Items]
Idaho Investment Tax Credits expiration year		2,031
Federal [Member]
Income Taxes [Line Items]
Operating Loss Carryforwards		$ 0
State and Local [Member]
Income Taxes [Line Items]
Operating Loss and Capital Loss Carryforwards		$ 1,200,000
State and Local [Member] | Earliest Tax Year [Member]
Income Taxes [Line Items]
Operating Loss and Capital Loss expiration year		2,021
State and Local [Member] | Latest Tax Year [Member]
Income Taxes [Line Items]
Operating Loss and Capital Loss expiration year		2,030
Subsequent Event [Member]
Income Taxes [Line Items]
Statutory Federal Income Tax Rate	21.00%

Income Taxes (Schedule of Incom

Income Taxes (Schedule of Income Tax Provision (Benefit)) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Current	$ 16,657	$ (6,178)	$ 128
Deferred	14,325	2,143	1,097
Net operating loss carryforwards	1,039	(290)	(6,793)
Income tax provision (benefit)	$ 32,021	$ (4,325)	$ (5,568)

Income Taxes (Schedule of Recon

Income Taxes (Schedule of Reconciliation of Income Tax Provision (Benefit)) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
U.S. federal statutory income tax	$ 41,466	$ 2,314	$ 9,151
REIT income not subject to federal income tax	(20,651)	(7,199)	(14,110)
U.S. tax rate change on deferred tax assets and liabilities	10,528
Intercompany profit-in-inventory elimination adjustment		1,465
Change in valuation allowance	140	162	488
State income taxes, net of federal income tax	2,608	(740)	(838)
Domestic production activities deduction	(1,511)	(2)
Permanent book-tax differences	(252)	(218)	(70)
Research and development credits	(294)	(689)
All other items	(13)	582	(189)
Income tax provision (benefit)	$ 32,021	$ (4,325)	$ (5,568)
Effective tax rate	27.00%	(65.40%)	(21.30%)

Income Taxes (Schedule of Compo

Income Taxes (Schedule of Components of Deferred Income Tax Assets and Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Pensions	$ 19,439	$ 37,423
Other postretirement employee benefits	7,891	13,002
Net operating loss carryforwards	54	983
Inventories	353	443
Tax credits	2,443	2,207
Nondeductible accruals	2,566	2,067
Incentive compensation	1,131	1,643
Employee benefits	1,037	1,444
Other	88	120
Total deferred tax assets	35,002	59,332
Valuation allowance	(790)	(650)	$ (500)
Deferred tax assets, net of valuation allowance	34,212	58,682
Timber and timberlands, net	(1,432)	(2,165)
Property, plant and equipment, net	(12,683)	(14,018)
Other	(301)	(448)
Total deferred tax liabilities	(14,416)	(16,631)
Deferred tax assets, net	$ 19,796	$ 42,051

Income Taxes (Summary of Tax Ye

Income Taxes (Summary of Tax Years Subject to Examination by Major Taxing Jurisdictions) (Details)	12 Months Ended
	Dec. 31, 2017
Federal [Member] | Earliest Tax Year [Member]
Income Tax Examination [Line Items]
Tax years subject to examination	2,013
Federal [Member] | Latest Tax Year [Member]
Income Tax Examination [Line Items]
Tax years subject to examination	2,017
State and Local [Member] | Arkansas [Member] | Earliest Tax Year [Member]
Income Tax Examination [Line Items]
Tax years subject to examination	2,014
State and Local [Member] | Arkansas [Member] | Latest Tax Year [Member]
Income Tax Examination [Line Items]
Tax years subject to examination	2,017
State and Local [Member] | Michigan [Member] | Earliest Tax Year [Member]
Income Tax Examination [Line Items]
Tax years subject to examination	2,013
State and Local [Member] | Michigan [Member] | Latest Tax Year [Member]
Income Tax Examination [Line Items]
Tax years subject to examination	2,017
State and Local [Member] | Minnesota [Member] | Earliest Tax Year [Member]
Income Tax Examination [Line Items]
Tax years subject to examination	2,013
State and Local [Member] | Minnesota [Member] | Latest Tax Year [Member]
Income Tax Examination [Line Items]
Tax years subject to examination	2,017
State and Local [Member] | Idaho [Member] | Earliest Tax Year [Member]
Income Tax Examination [Line Items]
Tax years subject to examination	2,014
State and Local [Member] | Idaho [Member] | Latest Tax Year [Member]
Income Tax Examination [Line Items]
Tax years subject to examination	2,017

Income Taxes (Summary of Reconc

Income Taxes (Summary of Reconciliation of Unrecognized Tax Benefits) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Balance at January 1	$ 850,000	$ 0
Additions for tax positions of prior years	8,000	850,000
Reduction for tax positions of prior years	(294,000)
Balance at December 31	$ 564,000	$ 850,000

Commitments and Contingencies88

Commitments and Contingencies (Narrative) (Details) $ in Thousands	Feb. 28, 2018USD ($)	Sep. 25, 2015USD ($)	May 23, 2012USD ($)	Sep. 30, 2017USD ($)	Jun. 30, 2016USD ($)	Mar. 31, 2016USD ($)	Dec. 31, 2017USD ($)Agreement	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Site Contingency [Line Items]
Operating leases expiration, year							2,033
Rent expense							$ 4,500	$ 4,200	$ 4,600
Loss contingency accrual, payments			$ 1,750
Loss contingency, damages sought, value		$ 9,800
Litigation settlement, expense				$ 5,000	$ 800	$ 200
Number of tolling agreement with EPA and DOT | Agreement							6
Litigation settlement date							February 9, 2018
Litigation filed date							February 12, 2018
Subsequent Event [Member]
Site Contingency [Line Items]
Litigation settlement amount	$ 6,000

Commitments and Contingencies89

Commitments and Contingencies (Future Minimum Rental Payments) (Details) $ in Thousands	Dec. 31, 2017USD ($)
Commitments And Contingencies Disclosure [Abstract]
2,018	$ 4,570
2,019	3,518
2,020	2,662
2,021	1,771
2,022	874
2023 and thereafter	992
Total	$ 14,387

Segment Information (Narrative)

Segment Information (Narrative) (Details)	12 Months Ended
	Dec. 31, 2017SegmentCustomer	Dec. 31, 2016Customer	Dec. 31, 2015Customer
Segment Reporting [Abstract]
Number of reportable segments | Segment	3
Concentration Risk, Customer | Customer	1	1	1
Concentration Risk, Percentage	10.00%	10.00%	10.00%

Segment Information (Summary Of

Segment Information (Summary Of Information By Business Segment) (Details) - USD ($) $ in Thousands		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
Segment Reporting Information [Line Items]
Segment Revenues		$ 175,244	$ 190,441	$ 163,229	$ 149,681	$ 155,681	$ 174,027	$ 141,495	$ 127,896	$ 678,595	$ 599,099	$ 575,336
Operating income		37,048	$ 43,793	$ 40,773	$ 23,909	25,716	$ 38,994	$ (34,228)	$ 5,072	145,523	35,554	58,907
Interest expense, net										(27,049)	(28,941)	(32,761)
Income before income taxes										118,474	6,613	26,146
Depreciation, depletion and amortization										29,912	34,190	38,105
Bond discount and deferred loan fees										1,480	1,979	1,481
Basis of real estate sold										6,827	8,011	7,012
Assets		953,079				927,681				953,079	927,681	1,016,612
Capital Expenditures	[1]									28,062	19,288	32,732
Operating Segments [Member]
Segment Reporting Information [Line Items]
Segment Revenues										750,011	656,193	629,078
Operating income										194,142	74,009	91,247
Depreciation, depletion and amortization										27,825	31,451	35,673
Assets		824,719				813,707				824,719	813,707	968,733
Capital Expenditures	[1]									25,930	18,913	32,163
Operating Segments [Member] | Resource [Member]
Segment Reporting Information [Line Items]
Segment Revenues										278,199	256,163	263,875
Operating income										106,105	81,918	76,350
Depreciation, depletion and amortization										20,476	24,090	28,807
Capital Expenditures	[1]									15,120	13,311	13,497
Operating Segments [Member] | Wood Products [Member]
Segment Reporting Information [Line Items]
Segment Revenues										441,157	367,426	336,214
Operating income										72,166	24,587	(5,235)
Depreciation, depletion and amortization										7,347	7,357	6,810
Assets		154,479				150,855				154,479	150,855	131,103
Capital Expenditures	[1]									10,723	5,491	18,482
Operating Segments [Member] | Real Estate [Member]
Segment Reporting Information [Line Items]
Segment Revenues										30,655	32,604	28,989
Operating income	[2]									18,576	(29,495)	16,849
Depreciation, depletion and amortization										2	4	56
Basis of real estate sold										7,114	8,518	7,394
Capital Expenditures	[1]									87	111	184
Operating Segments [Member] | Resource and Real Estate [Member]
Segment Reporting Information [Line Items]
Assets	[3]	670,240				662,852				670,240	662,852	837,630
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Segment Revenues	[4]									(71,416)	(57,094)	(53,742)
Operating income										(2,705)	(3,001)	3,283
Basis of real estate sold										(287)	(507)	(382)
Corporate [Member]
Segment Reporting Information [Line Items]
Operating income										(48,619)	(38,455)	(32,340)
Depreciation, depletion and amortization										607	760	951
Assets		$ 128,360				$ 113,974				128,360	113,974	47,879
Capital Expenditures	[1]									$ 2,132	$ 375	$ 569
[1]	Excludes the acquisition of timber and timberlands.
[2]	In the second quarter of 2016, we sold approximately 172,000 acres of timberlands located in central Idaho for $114 million at a loss of $48.5 million before taxes.
[3]	Assets are shown on a combined basis for the Resource and Real Estate segments, as we do not report assets separately to management for these segments.
[4]	Intersegment revenues are based on prevailing market prices of logs sold by our Resource segment to the Wood Products segment.

Segment Information (Summary 92

Segment Information (Summary Of Information By Business Segment) (Parenthetical) (Details) $ in Millions	3 Months Ended
	Jun. 30, 2016USD ($)a
Segment Reporting Information [Line Items]
Acres sold through timberland sale | a	172,000
Land Sales	$ 114
Operating Segments [Member] | Real Estate [Member]
Segment Reporting Information [Line Items]
Net loss	$ 48.5

Segment Information (Schedule o

Segment Information (Schedule of Revenue by Geographic Area) (Details) - USD ($) $ in Thousands	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
Revenues	$ 175,244	$ 190,441	$ 163,229	$ 149,681	$ 155,681	$ 174,027	$ 141,495	$ 127,896	$ 678,595	$ 599,099	$ 575,336
United States
Revenues									676,956	597,899	573,398
Canada
Revenues									481	173	851
Mexico
Revenues									$ 1,158	$ 1,027	919
Other
Revenues											$ 168

Financial Results by Quarter 94

Financial Results by Quarter (Unaudited) Financial Results by Quarter (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	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 [Abstract]
Revenues	$ 175,244		$ 190,441		$ 163,229		$ 149,681		$ 155,681		$ 174,027		$ 141,495		$ 127,896		$ 678,595	$ 599,099	$ 575,336
Operating income (loss)	37,048		43,793		40,773		23,909		25,716		38,994		(34,228)		5,072		145,523	35,554	58,907
Net income (loss)	$ 11,588		$ 33,700		$ 24,244		$ 16,921		$ 14,373		$ 27,646		$ (31,238)		$ 157		$ 86,453	$ 10,938	$ 31,714
Net income (loss) per share
Basic (in dollars per share)	$ 0.28	[1]	$ 0.83	[1]	$ 0.59	[1]	$ 0.41	[1]	$ 0.35	[1]	$ 0.68	[1]	$ (0.77)	[1]	$ 0	[1]	$ 2.12	$ 0.27	$ 0.78
Diluted (in dollars per share)	$ 0.28	[1]	$ 0.82	[1]	$ 0.59	[1]	$ 0.41	[1]	$ 0.35	[1]	$ 0.68	[1]	$ (0.77)	[1]	$ 0	[1]	$ 2.10	$ 0.27	$ 0.77
[1]	Per share amounts are computed independently for each of the quarters presented. Therefore, the sum of the quarterly per share amounts may not equal the total computed for the year.

Financial Results by Quarter 95

Financial Results by Quarter (Unaudited) - (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2017
Effect Of Fourth Quarter Events [Line Items]
Deltic merger-related costs		$ 3,409
Deltic [Member]
Effect Of Fourth Quarter Events [Line Items]
Deltic merger-related costs	$ 3,400