Summary of Principal Accounting Policies Summary of Principal Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2013
Accounting Policies [Abstract]
Consolidation	CONSOLIDATION The Consolidated Financial Statements include the accounts of Potlatch Corporation and its subsidiaries after elimination of significant intercompany transactions and accounts. There are no significant unconsolidated subsidiaries. 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. As discussed in Note 2: REIT Conversion, we converted to a Real Estate Investment Trust, or REIT, effective January 1, 2006.
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 are described in further detail in this section and the following Notes to Consolidated Financial Statements. Significant estimates include timber volumes, pension and postretirement obligation assumptions, environmental liabilities, fair value of derivative instruments and assumptions utilized for asset and disposal group impairment tests
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 over each employee’s required service period. See Note 16: Equity-Based Compensation Plans for more information about our equity-based compensation.
Inventories	INVENTORIES Inventories are stated at the lower of cost or market. The last-in, first-out method is used to determine cost of logs, lumber and plywood for most of our operations. The average cost method is used to determine cost of all other inventories. 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. Estimated useful lives range from 30 to 40 years for buildings and structures and 2 to 25 years for equipment. 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 or amortization are removed from the accounts. Any gains or losses are included in earnings.
Timber and Timberland	TIMBER AND TIMBERLANDS Timber and timberlands are valued at cost less accumulated depletion and amortization. For fee timber, the capitalized cost includes costs related to stand establishment, such as site preparation, including all costs of preparing the land for planting, cost of seeds or seedlings, tree planting, including labor, materials, depreciation of company-owned equipment and the cost of contract services. Upon completion of planting activities and field inspection to assure the planting operation was successful, a plantation will be considered “established.” Subsequent expenditures made to maintain the integrity or enhance the growth of an established plantation or stand are expensed. Post-establishment expenses include release spray treatments, pest control activities, thinning operations, fertilization and replanting seedlings lost through mortality. Expenditures for forest management consist of regularly recurring items necessary for ownership and administration of timber producing property such as fire protection, property taxes and insurance, silviculture costs incurred subsequent to stand establishment, cruising (physical inventory), property maintenance and salaries, supplies, travel, record-keeping and other normal recurring administrative personnel costs. These expenditures are accounted for as current operating expenses. Timberland purchased on the open market is capitalized and the cost is allocated to the relative values of the component items as appraised, such as timberland, merchantable sawlogs, merchantable pulpwood, reproduction (young growth not merchantable), logging roads and other land improvements. The capitalized cost includes purchase price, title search and title recording, transfer taxes and fees, timber cruises, appraisals and running of boundary lines. The aggregate estimated volume of current standing timber inventory is updated at least annually to reflect increases in merchantable timber due to reclassification of young growth to merchantable timber, the annual growth rates of merchantable timber and the acquisition of additional merchantable timber, and to reflect decreases due to timber harvests and land sales. Timber volumes are estimated from cruises of the timber tracts, which are completed on our timberlands on approximately a five to ten year cycle. Since the individual cruises collect field data at different times for specific sites, the growth model projects standing inventory from the cruise date to a common reporting date. Annual growth rates for the merchantable inventory have historically been in the range of 2%-5%. Reproduction accounts are reviewed annually, and dollars are transferred from reproduction accounts to merchantable timber accounts on a reasonable and consistent basis. Volumes and the related accumulated costs are tracked and, as the timber is harvested, the cost is amortized to depletion. Depletion represents the amount charged to expense for logs cut from fee timber. Generally, rates at which timber is depleted are calculated annually for each of our Resource regions by dividing the beginning of year balance of the timber accounts by the forest inventory volume, after inventory updates for growth projection adjustments and new timber cruises. The base cost of logging roads, such as the clearing, grading, and ditching, is not amortized and remains a capitalized item until obliteration or other disposition, while other portions of the initial 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 roads that will not become part of our road system 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. Cash generated from real estate sales is included as an operating activity in our Consolidated Statements of Cash Flows, and is adjusted for the basis of real estate sold.
Like-Kind Exchange and Restricted Cash	LIKE-KIND EXCHANGES AND RESTRICTED CASH In order to acquire and sell assets, primarily timberlands, in a tax efficient manner, we sometimes enter into like-kind exchange (LKE) tax-deferred transactions. There are two main types of LKE transactions: forward transactions, in which property is sold and the proceeds are reinvested by acquiring similar property; and reverse transactions, in which property is acquired and similar property is subsequently sold by us. Both forward and reverse transactions must be completed within prescribed time periods under Internal Revenue Code section 1031. We use a qualified intermediary to facilitate LKE transactions. Proceeds from forward transactions are held by the intermediary and are classified as restricted cash, within non-current other assets, because the funds must be reinvested in similar properties. If the acquisition of suitable LKE properties is not completed within 180 days of the sale of the company-owned property, the proceeds are distributed to us by the intermediary and are reclassified as available cash and applicable income taxes are determined. In the case of reverse transactions in which we have not yet completed LKE sales of company-owned land to match with property purchased on our behalf by the intermediary, the amount associated with the property purchased on our behalf but not yet matched with LKE sales is classified as a non-current asset and included in “Timber and timberlands, net” in our Consolidated Balance Sheets and as “Additions to timber and timberlands” in the investing activities section of our 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. Budget estimates are adjusted periodically to reflect changing business conditions, and operations are reviewed, as appropriate, for impairment using the most current data available. In certain circumstances we may also use fair market value to determine the carrying value of certain assets. 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. Our primary obligations relate to asbestos located within our manufacturing facilities and a landfill site. We have recorded assets and corresponding liabilities that are not material to our financial position or results of operations. We have also identified situations that would have resulted in the recognition of additional asset retirement obligations, except for an inability to reasonably estimate the fair value of the liability. Most of these situations relate to asbestos located within our manufacturing facilities where a settlement date or range of settlement dates cannot be specified. 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 and Consolidated Statements of Comprehensive Income in the period that includes the enactment date of the rate change. We record a valuation allowance to reduce the carrying amounts of deferred tax assets if it is more likely than not that such deferred tax assets will not be realized.
Revenue Recognition	REVENUE RECOGNITION We recognize revenue from the sale of timber when legal ownership and the risk of loss transfers to the buyer and the quantity sold is determinable. The company sells timber under delivered log agreements as well as through sales of standing timber, or stumpage. For delivered sales, revenue, which includes amounts billed for shipping and handling (logging and hauling of timber), is recognized when the log is delivered to the customer. Stumpage is sold using pay-as-cut, timber deed or lump-sum sale agreements. Under a pay-as-cut sales contract, the purchaser acquires the right to harvest specified timber on a tract, at an agreed upon price per unit. The sale and any related advances are recognized as revenue as the purchaser harvests the timber on the tract. Under a timber deed sale, the buyer agrees to purchase and harvest specified timber on a tract of land over the term of the contract, the risk of loss and title to the trees transfer to the buyer when the contract is signed and the buyer pays the full purchase price when the contract is signed. Revenue from a timber deed sale is recognized when the contract is signed. Under a lump-sum sale, the parties agree to a purchase price for all the timber available for harvest on a tract of land. Generally the purchase price is paid when the contract is signed. Title to the timber and risk of loss transfers to the buyer as the timber is harvested. Therefore, revenue under a lump-sum sale is recognized over the term of the contract based on the timber harvested compared to the total estimated timber available to be harvested. An adjustment may be required to the extent the actual timber harvested is different than the estimate of timber available. Substantially all of our real estate sales are considered cash sales, as we receive the entire consideration in cash at closing. Also at closing, all risks and rewards of ownership are transferred to the buyer, and we do not have a substantial continuing involvement in any of our properties after sales are consummated. We recognize revenue under the full accrual method for cash sales of real estate when the sale is consummated (i.e., at closing). Sales of properties that qualify for LKE tax-deferred treatment involve a third party intermediary that receives proceeds related to the property sold and holds the proceeds for reinvestment in like kind property. The proceeds are recorded as revenue when the third party intermediary receives them. 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 for sales 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. Shipping terms for wood products and related by-products depend upon the sales agreement with the customer. Revenue is recognized net of any sales taxes collected. Sales taxes, when collected, are recorded as a current liability and remitted to the appropriate governmental entities.
Shipping and Handling Costs	SHIPPING AND HANDLING COSTS Costs for shipping and handling of manufactured goods are included in cost of goods sold in our Consolidated Statements of Income.