Compass Minerals International (CMP) 10-K 22 Feb 16 2015 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2015	Feb. 17, 2016	Jun. 30, 2015
Document and Entity Information [Abstract]
Entity Registrant Name	COMPASS MINERALS INTERNATIONAL INC
Entity Central Index Key	1,227,654
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 Public Float			$ 2,768,243,921
Entity Common Stock, Shares Outstanding		33,739,460
Document Fiscal Year Focus	2,015
Document Fiscal Period Focus	FY
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2015

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 58.4	$ 266.8
Receivables, less allowance for doubtful accounts of $1.3 in 2015 and $1.4 in 2014	147.8	213
Inventories	275.3	199
Deferred income taxes, net	0	9.7
Other	30.8	14.2
Total current assets	512.3	702.7
Property, plant and equipment, net	800.7	700.9
Intangible assets, net	85.3	106.2
Goodwill	58.1	68.5
Investment in equity investee	116.4	0
Other	56.1	58.9
Total assets	1,628.9	1,637.2
Current liabilities:
Current portion of long-term debt	4.9	3.9
Accounts payable	80.7	97.6
Accrued expenses	48.9	60.6
Accrued salaries and wages	15.2	24.4
Income taxes payable	14.8	44.4
Accrued interest	6.3	6.8
Total current liabilities	170.8	237.7
Long-term debt, net of current portion	722.1	622.5
Deferred income taxes, net	71.3	88.9
Other noncurrent liabilities	$ 25	$ 34.5
Commitments and contingencies (Note 12)
Stockholders' equity:
Common Stock: $0.01 par value, authorized shares - 200,000,000; issued shares - 35,367,264	$ 0.4	$ 0.4
Additional paid-in capital	91.7	82.5
Treasury stock, at cost – 1,665,731 shares at December 31, 2015 and 1,757,997 shares at December 31, 2014	(3.2)	(3.3)
Retained earnings	659.1	589.5
Accumulated other comprehensive loss	(108.3)	(15.5)
Total stockholders' equity	639.7	653.6
Total liabilities and stockholders' equity	$ 1,628.9	$ 1,637.2

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Current assets:
Allowance for doubtful accounts	$ 1.3	$ 1.4
Stockholders' equity:
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	200,000,000	200,000,000
Common stock, shares issued (in shares)	35,367,264	35,367,264
Treasury stock, shares (in shares)	1,665,731	1,757,997

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Statement [Abstract]
Sales	$ 1,098.7	$ 1,282.5	$ 1,129.6
Shipping and handling cost	261.5	337.7	301.7
Product cost (Note 4)	507.1	523.4	541.9
Gross profit	330.1	421.4	286
Selling, general and administrative expenses	108.7	110.4	100.4
Operating earnings	221.4	311	185.6
Other (income) expense:
Interest expense	21.5	20.1	17.9
Other, net	(14.6)	(0.9)	(6.4)
Earnings before income taxes	214.5	291.8	174.1
Income tax expense	55.3	73.9	43.3
Net earnings	$ 159.2	$ 217.9	$ 130.8
Basic net earnings per common share (in dollars per share)	$ 4.70	$ 6.45	$ 3.89
Diluted net earnings per common share (in dollars per share)	$ 4.69	$ 6.44	$ 3.88
Weighted-average common shares outstanding (in thousands):
Basic (in shares)	33,677	33,557	33,403
Diluted (in shares)	33,692	33,581	33,420
Cash dividends per share (in dollars per share)	$ 2.64	$ 2.40	$ 2.18

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement of Comprehensive Income [Abstract]
Net earnings	$ 159.2	$ 217.9	$ 130.8
Other comprehensive income (loss):
Unrealized gain (loss) from change in pension costs, net of tax of $(1.2), $(0.1) and $(0.2) in 2015, 2014 and 2013	5.2	0.3	0.3
Unrealized gain (loss) on cash flow hedges, net of tax of $(0.3), $1.4 and $(0.6) in 2015, 2014 and 2013	0.4	(2.3)	1
Cumulative translation adjustment	(98.4)	(48)	(24.4)
Comprehensive income	$ 66.4	$ 167.9	$ 107.7

Consolidated Statements of Com6

Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement of Comprehensive Income [Abstract]
Unrealized gain (loss) from change in pension costs, tax	$ (1.2)	$ (0.1)	$ (0.2)
Unrealized gain (loss) on cash flow hedges, tax	$ (0.3)	$ 1.4	$ (0.6)

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) $ in Millions	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Treasury Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Balance at Dec. 31, 2012	$ 503.5	$ 0.4	$ 54.5	$ (4)	$ 395	$ 57.6
Comprehensive income	107.7				130.8	(23.1)
Dividends on common stock/equity awards	(73.3)				(73.3)
Shares issued for stock units	0		(0.1)	0.1
Income tax benefits from equity awards	0.6		0.6
Stock options exercised	10.6		10.3	0.3
Stock-based compensation	5.1		5.1
Balance at Dec. 31, 2013	554.2	0.4	70.4	(3.6)	452.5	34.5
Comprehensive income	167.9				217.9	(50)
Dividends on common stock/equity awards	(80.7)		0.2		(80.9)
Shares issued for stock units	0		(0.1)	0.1
Income tax deficiencies from equity awards	(0.2)		(0.2)
Stock options exercised	7.5		7.3	0.2
Stock-based compensation	4.9		4.9
Balance at Dec. 31, 2014	653.6	0.4	82.5	(3.3)	589.5	(15.5)
Comprehensive income	66.4				159.2	(92.8)
Dividends on common stock/equity awards	(89.4)		0.2		(89.6)
Income tax benefits from equity awards	0.5		0.5
Stock options exercised	2.5		2.4	0.1
Stock-based compensation	6.1		6.1
Balance at Dec. 31, 2015	$ 639.7	$ 0.4	$ 91.7	$ (3.2)	$ 659.1	$ (108.3)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Cash flows from operating activities:
Net earnings	$ 159.2	$ 217.9	$ 130.8
Adjustments to reconcile net earnings to net cash flows provided by operating activities:
Depreciation, depletion and amortization	78.3	78	73
Finance fee amortization	1.2	1.2	1.2
Early extinguishment and refinancing of long-term debt	0	6.9	0
Stock-based compensation	6.1	4.9	5.1
Deferred income taxes	(0.1)	3.6	(0.2)
Gain from insurance settlement	0	(83.3)	0
Other, net	4.2	0.8	1.7
Asset impairment charges, Goderich tornado	0	0	0.2
Insurance receipts for operating purposes, Goderich tornado	0	11.9	5.5
Changes in operating assets and liabilities, net of acquisition:
Receivables	59	(4.4)	(71.7)
Inventories	(90.5)	(21.9)	45.7
Other assets	(11.3)	(4.7)	1.3
Accounts payable, income taxes payable and accrued expenses	(65.7)	35.5	45.1
Other liabilities	(2.5)	(3.5)	0.6
Net cash provided by operating activities	137.9	242.9	238.3
Cash flows from investing activities:
Capital expenditures	(217.6)	(125.2)	(122.7)
Investment in equity method investee	(116.4)	0	0
Insurance receipts for investment purposes, Goderich tornado	0	19.4	14.2
Acquisition of a business	0	(86.5)	0
Other, net	(1.4)	3.1	2.4
Net cash used in investing activities	(335.4)	(189.2)	(106.1)
Cash flows from financing activities:
Proceeds from the issuance of long-term debt	100	250	0
Proceeds from revolving credit facility borrowings	50	0	0
Principal payments on long-term debt	(3.9)	(102.4)	(3.9)
Principal payments on revolving credit facility borrowings	(45.5)	0	0
Premium and other payments to refinance debt	0	(5.5)	0
Deferred financing costs	0	(4.1)	(0.6)
Dividends paid	(89.4)	(80.7)	(73.1)
Proceeds received from stock option exercises	2.5	7.5	10.6
Excess tax benefits (deficiencies) from equity compensation awards	0.5	(0.2)	0.6
Net cash provided by (used in) financing activities	14.2	64.6	(66.4)
Effect of exchange rate changes on cash and cash equivalents	(25.1)	(11.1)	(6.3)
Net change in cash and cash equivalents	(208.4)	107.2	59.5
Cash and cash equivalents, beginning of the year	266.8	159.6	100.1
Cash and cash equivalents, end of year	58.4	266.8	159.6
Supplemental cash flow information:
Interest paid, net of amounts capitalized	20.5	13.1	17.4
Income taxes paid, net of refunds	$ 89.4	36.2	$ 24.7
In connection with the acquisition of Wolf Trax, Inc., the Company assumed liabilities as follows (in millions):
Fair value of assets acquired		99.2
Cash paid during the year ended December 31, 2014		(86.5)
Liabilities assumed		$ 12.7

ORGANIZATION AND FORMATION

ORGANIZATION AND FORMATION	12 Months Ended
	Dec. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
ORGANIZATION AND FORMATION	ORGANIZATION AND FORMATION Compass Minerals International, Inc., through its subsidiaries ("CMP", "Compass Minerals", or the "Company"), is a producer and marketer of essential mineral products with manufacturing sites in North America and the United Kingdom ("U.K."). Its principal products are salt, consisting of sodium chloride and magnesium chloride, and sulfate of potash ("SOP"), a specialty fertilizer the Company markets under the trade name Protassium+. Additionally, the Company sells various premium micronutrient products under its Wolf Trax brand. The Company provides highway deicing products to customers in North America and the U.K., and plant nutrients to growers and fertilizer distributors worldwide. The Company also produces and markets consumer deicing and water conditioning products, ingredients used in consumer and commercial food preparation, and other mineral-based products for consumer, agricultural and industrial applications. Compass Minerals also provides records management services to businesses located in the U.K. Compass Minerals International, Inc. is a holding company with no operations other than those of its wholly owned subsidiaries.

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	12 Months Ended
	Dec. 31, 2015
Accounting Policies [Abstract]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES a. Management Estimates: The preparation of financial statements in conformity with U.S. generally accepted accounting principles ("GAAP") as included in the Accounting Standards Codification requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Actual results could differ from those estimates. b. Basis of Consolidation: The Company’s consolidated financial statements include the accounts of Compass Minerals International, Inc. and its wholly owned domestic and foreign subsidiaries. All significant intercompany balances and transactions have been eliminated in consolidation. c. Foreign Currency: Assets and liabilities are translated into U.S. dollars at end of period exchange rates. Revenues and expenses are translated using the monthly average rates of exchange during the year. Adjustments resulting from the translation of foreign-currency financial statements into the reporting currency, U.S. dollars, are included in accumulated other comprehensive income (loss). The Company recorded foreign exchange losses of approximately $(33.7) million , $(18.4) million and $(15.0) million in 2015 , 2014 and 2013 , respectively, in accumulated other comprehensive income (loss) related to intercompany notes which were deemed to be of long-term investment nature. Aggregate exchange gains (losses) from transactions denominated in a currency other than the functional currency, which are included in other income, for the years ended December 31, 2015 , 2014 and 2013 , were $13.9 million , $6.6 million and $4.9 million , respectively. d. Revenue Recognition: The Company typically recognizes revenue at the time of shipment to the customer, which coincides with the transfer of title and risk of ownership to the customer. Sales represent billings to customers net of sales taxes charged for the sale of the product. Sales include amounts charged to customers for shipping and handling costs, which are expensed when the related product is sold. e. Cash and Cash Equivalents: The Company considers all investments with original maturities of three months or less to be cash equivalents. The Company maintains the majority of its cash in bank deposit accounts with several commercial banks with high credit ratings in the U.S., Canada and Europe. Typically, the Company has bank deposits in excess of federally insured limits. Currently, the Company does not believe it is exposed to significant credit risk on its cash and cash equivalents. f. Accounts Receivable and Allowance for Doubtful Accounts: Receivables consist almost entirely of trade accounts receivable. Trade accounts receivable are recorded at the invoiced amount and do not bear interest. The allowance for doubtful accounts is the Company’s best estimate of the amount of probable credit losses in its existing accounts receivable. The Company determines the allowance based on historical write-off experience by business line and a current assessment of its portfolio. The Company reviews its past due account balances for collectability and adjusts its allowance for doubtful accounts accordingly. Account balances are charged off against the allowance when the Company believes it is probable that the receivable will not be recovered. g. Inventories: Inventories are stated at the lower of cost or market. Finished goods and raw material and supply costs are valued using the average cost method. Raw materials and supplies primarily consist of raw materials purchased to aid in the production of mineral products, maintenance materials and packaging materials. Finished goods are primarily comprised of salt, magnesium chloride and plant nutrition products readily available for sale. Substantially all costs associated with the production of finished goods at the Company’s producing locations are captured as inventory costs. As required by U.S. GAAP, a portion of the fixed costs at a location are not included in inventory and are expensed as a product cost if production at that location is determined to be abnormally low in any period. Additionally, since the Company’s products are often stored at third-party warehousing locations, the Company includes in the cost of inventory the freight and handling costs necessary to move the product to storage until the product is sold to a customer. h. Other Current Assets: In the fourth quarter of 2015, the Company began marketing assets it held which were used for farming. The Company intends to sell these assets in 2016. The Company has performed an impairment analysis and concluded that the fair market value of these assets exceeds their carrying value. These assets have been recorded at the lower of cost or market less selling costs in other current assets as of December 31, 2015. The amounts classified as held for sale include inventory of approximately $2.7 million , property, plant and equipment of approximately $2.8 million and water rights of approximately $5.2 million . The remaining amounts as of December 31, 2015, and the amounts recorded as of December 31, 2014, consist principally of prepaid expenses. i. Property, Plant and Equipment: Property, plant and equipment is stated at cost and includes capitalized interest. The costs of replacements or renewals, which improve or extend the life of existing property, are capitalized. Maintenance and repairs are expensed as incurred. Upon retirement or disposition of an asset, any resulting gain or loss is included in the Company’s operating results. Property, plant and equipment also includes mineral interests. The mineral interests for the Company’s Winsford U.K. mine are owned. The Company leases probable mineral reserves at its Cote Blanche and Goderich mines, its Ogden facility and several of its other facilities. These leases have varying terms, and many provide for a royalty payment to the lessor based on a specific amount per ton of mineral extracted or as a percentage of revenue. The Company’s rights to extract minerals are contractually limited by time. The Cote Blanche mine is operated under land and mineral leases. The mineral lease for the Cote Blanche mine expires in 2060 with two additional 25 -year renewal periods. The Goderich mine mineral reserve lease expires in 2022 with our option to renew until 2043 after demonstrating to the lessor that the mine’s useful life is greater than the lease’s term. The Ogden facility mineral reserve lease renews annually. The Company believes it will be able to continue to extend lease agreements as it has in the past, at commercially reasonable terms, without incurring substantial costs or material modifications to the existing lease terms and conditions, and therefore, management believes that assigned lives are appropriate. The Company’s leased mineral interests are primarily depleted on a units-of-production basis over the respective estimated lives of mineral deposits not to exceed 99 years. The weighted average amortization period for these probable mineral reserves is 81 years as of December 31, 2015 . The Company also owns other mineral properties. The weighted average life for these probable owned mineral reserves is 42 years as of December 31, 2015 based upon current annual capacities. Buildings and structures are depreciated on a straight line basis over lives generally ranging from 10 to 30 years. Portable buildings generally have shorter lives than permanent structures. Leasehold and building improvements typically have shorter estimated lives of 5 to 20 years or lower based on the life of the lease to which the improvement relates. The Company’s other fixed assets are amortized on a straight-line basis over their respective lives. The following table summarizes the estimated useful lives of the Company’s different classes of property, plant and equipment: Years Land improvements 10 to 25 Buildings and structures 10 to 30 Leasehold and building improvements 5 to 40 Machinery and equipment – vehicles 3 to 10 Machinery and equipment – other mining and production 3 to 50 Office furniture and equipment 3 to 10 Mineral interests 20 to 99 The Company has capitalized computer software costs of $28.0 million and $16.9 million as of December 31, 2015 and 2014 , respectively, recorded in property, plant and equipment. The capitalized costs are being amortized over 5 years. The Company recorded $2.2 million , $1.6 million and $1.3 million of amortization expense for 2015 , 2014 and 2013 , respectively. The Company recognizes and measures obligations related to the retirement of tangible long-lived assets in accordance with applicable U.S. GAAP. Asset retirement obligations are not material to the Company’s financial position, results of operations or cash flows. The Company reviews its long-lived assets and the related mineral reserves for impairment whenever events or changes in circumstances indicate the carrying amounts of such assets may not be recoverable. If an indication of a potential impairment exists, recoverability of the respective assets is determined by comparing the forecasted undiscounted net cash flows of the operation to which the assets relate, to the carrying amount, including associated intangible assets, of such operation. If the operation is determined to be unable to recover the carrying amount of its assets, then intangible assets are written down first, followed by the other long-lived assets of the operation, to fair value. Fair value is determined based on discounted cash flows or appraised values, depending upon the nature of the assets. j. Goodwill and Intangible Assets: The Company amortizes its intangible assets deemed to have finite lives on a straight-line basis over their estimated useful lives which, for Compass Minerals, range from 5 to 50 years. The Company reviews goodwill and other indefinite-lived intangible assets annually for impairment. In addition, goodwill and other intangible assets are reviewed when an event or change in circumstances indicates the carrying amounts of such assets may not be recoverable. During the fourth quarter of 2015, the Company voluntarily changed the date of its annual goodwill and indefinite-lived intangible assets impairment testing from December 1, to the first day of the fourth quarter, October 1. This voluntary change is preferable under the circumstances as it provides the Company with additional time to complete its annual goodwill and indefinite-lived intangible asset impairment testing in advance of its year-end reporting and results in better alignment with the Company’s strategic forecasting and budgeting process. The voluntary change in accounting principle related to the annual testing date will not delay, accelerate or avoid an impairment charge. This change is not applied retrospectively as it is impracticable to do so because retrospective application would require application of significant estimates and assumptions with the use of hindsight. Accordingly, the change will be applied prospectively. k. Investment Our investment in a Brazilian manufacturer and distributor of specialty plant nutrients (see Note 3) is accounted for using the equity method, as our ownership interest is 50% or less and allows us to exercise significant influence over the operating and financial policies of the investee. In accordance with the equity method, our original investment was recorded at cost (including certain capitalized transaction costs) and will be adjusted by our share of the investee’s undistributed earnings and losses. l. Other Noncurrent Assets: Other noncurrent assets include deferred financing costs of $8.5 million as of December 31, 2015 and 2014 with accumulated amortization of $3.9 million and $2.7 million as of December 31, 2015 and 2014 , respectively. In connection with the debt refinancing in June 2014, the Company incurred approximately $8.1 million of costs, including $4.1 million of fees that were capitalized as deferred financing costs related to the $250.0 million senior notes (" 4.875% Senior Notes") and $4.0 million in call premiums. The $4.0 million paid for call premiums along with the write-off of $1.4 million of the Company’s unamortized deferred financing costs and approximately $1.5 million of original issue discount, each related to the $100.0 million senior notes (" 8% Senior Notes"), were recorded in other expense in the consolidated statements of operations for 2014 . In December 2013, the Company amended and extended to August 2017 (previously October 2015) its existing revolving credit facility. In connection with this transaction, the Company paid and capitalized approximately $0.6 million of deferred financing costs. Deferred financing costs are being amortized to interest expense over the terms of the debt to which the costs relate. Certain inventories of spare parts and related inventory, net of reserve, of approximately $11.0 million and $13.7 million at December 31, 2015 and 2014 , respectively, which will be utilized with respect to long-lived assets, have been classified in the consolidated balance sheets as other noncurrent assets. The Company sponsors a non-qualified defined contribution plan for certain of its executive officers and key employees as described in Note 9. As of December 31, 2015 and 2014 , investments in marketable securities representing amounts deferred by employees, Company contributions and unrealized gains or losses totaling $1.6 million and $1.9 million , respectively, were included in other noncurrent assets in the consolidated balance sheets. The marketable securities are classified as trading securities and accordingly, gains and losses are recorded as a component of other (income) expense, net in the consolidated statements of operations. m. Income Taxes: The Company accounts for income taxes using the liability method in accordance with the provisions of U.S. GAAP. Under the liability method, deferred taxes are determined based on the differences between the financial statement and the tax basis of assets and liabilities using enacted tax rates in effect in the years in which the differences are expected to reverse. The Company’s foreign subsidiaries file separate company returns in their respective jurisdictions. The Company recognizes potential liabilities in accordance with applicable U.S. GAAP for anticipated tax issues in the U.S. and other tax jurisdictions based on its estimate of whether, and the extent to which, additional taxes will be due. If payment of these amounts ultimately proves to be unnecessary, the reversal of the liabilities would result in tax benefits being recognized in the period when the Company determines the liabilities are no longer necessary. If the Company’s estimate of tax liabilities proves to be less than the ultimate assessment, a further charge to expense would result. Any penalties and interest that are accrued on the Company’s uncertain tax positions are included as a component of income tax expense. In evaluating the Company’s ability to realize deferred tax assets, the Company considers the sources and timing of taxable income, including the reversal of existing temporary differences, the ability to carryback tax attributes to prior periods, qualifying tax-planning strategies, and estimates of future taxable income exclusive of reversing temporary differences. In determining future taxable income, the Company’s assumptions include the amount of pre-tax operating income according to different state, federal and international taxing jurisdictions, the origination of future temporary differences, and the implementation of feasible and prudent tax-planning strategies. If the Company determines that a portion of its deferred tax assets will not be realized, a valuation allowance is recorded in the period that such determination is made. In the future, if the Company determines, based on the existence of sufficient evidence, that more or less of the deferred tax assets are more likely than not to be realized, an adjustment to the valuation allowance will be made in the period such a determination is made. n. Environmental Costs: Environmental costs, other than those of a capital nature, are accrued at the time the exposure becomes known and costs can be reasonably estimated. Costs are accrued based upon management’s estimates of all direct costs. The Company’s environmental accrual was $1.4 million and $1.5 million at December 31, 2015 and 2014 , respectively. o. Equity Compensation Plans: The Company has equity compensation plans under the oversight of the board of directors of Compass Minerals, whereby stock options, restricted stock units, deferred stock units and performance stock units are granted to employees or directors of the Company. See Note 13 for additional discussion. p. Earnings per Share: The Company’s participating securities are accounted for in accordance with guidance related to the computation of earnings per share under the two-class method. The two-class method requires allocating the Company’s net earnings to both common shares and participating securities based upon their rights to receive dividends. Basic earnings per share is computed by dividing net earnings available to common shareholders by the weighted-average number of outstanding common shares during the period. Diluted earnings per share reflects the potential dilution that could occur under the more dilutive of either the treasury stock method or the two-class method for calculating the weighted-average number of outstanding common shares. The treasury stock method is calculated assuming unrecognized compensation expense, income tax benefits and proceeds from the potential exercise of employee stock options are used to repurchase common stock. q. Derivatives: The Company is exposed to the impact of fluctuations in the purchase price of natural gas consumed in operations. The Company hedges portions of its risk of changes in natural gas prices through the use of derivative agreements. The Company accounts for derivative financial instruments in accordance with applicable U.S. GAAP, which requires companies to record derivative financial instruments as assets or liabilities measured at fair value. Accounting for the changes in the fair value of a derivative depends on its designation and effectiveness. Derivatives qualify for treatment as hedges when there is a high correlation between the change in fair value of the derivative instrument and the related change in value of the underlying hedged item. For qualifying hedges, the effective portion of the change in fair value is recognized through earnings when the underlying transaction being hedged affects earnings, allowing a derivative’s gains and losses to offset related results from the hedged item in the statements of operations. For derivative instruments that are not accounted for as hedges, or for the ineffective portions of qualifying hedges, the change in fair value is recorded through earnings in the period of change. The Company formally documents, designates, and assesses the effectiveness of transactions that receive hedge accounting treatment initially and on an ongoing basis. The Company does not engage in trading activities with its financial instruments. r. Concentration of Credit Risk: The Company sells its salt and magnesium chloride products to various governmental agencies, manufacturers, distributors and retailers primarily in the Midwestern U.S., and throughout Canada and the U.K. The Company’s plant nutrition products are sold across North America and internationally. No single customer or group of affiliated customers accounted for more than 10% of the Company’s sales in any year during the three year period ended December 31, 2015 , or more than 10% of accounts receivable at December 31, 2015 or 2014 . s. Recent Accounting Pronouncements: In November 2015, the Financial Accounting Standards Board ("FASB") issued guidance which simplifies the presentation of deferred income taxes by eliminating the requirement that an entity separate deferred income tax assets and liabilities into current and noncurrent in a classified statement of financial position. Under this guidance, deferred tax assets and liabilities are required to be classified as noncurrent. The amendments are effective for financial statements issued for annual periods beginning after December 15, 2016, and interim periods within those annual periods. Early adoption is permitted for all entities as of the beginning of an interim or annual reporting period. The Company has elected to prospectively adopt the accounting standard as of the beginning of the Company's fourth quarter of 2015. Prior periods in our Consolidated Financial Statements were not retrospectively adjusted. In July 2015, the FASB issued guidance that requires entities to measure inventory within the scope of the standard at the lower of cost or net realizable value. "Net realizable value" is defined as the estimated selling prices in the ordinary course of business, less reasonably predictable costs of completion, disposal and transportation. The guidance is effective for fiscal years, and interim periods within those years, beginning after December 15, 2016. Early adoption is permitted. The Company does not expect that this guidance will have a material impact on its consolidated financial statements. In April 2015, the FASB issued guidance about whether fees paid by customers in cloud computing arrangements include a software license. If a cloud computing arrangement includes a software license, a customer should account for the software license element in a manner consistent with previously issued guidance for software licenses. If the arrangement does not include a software license, a customer should account for the arrangement as a service contract. The guidance is effective for fiscal years, and interim periods within those years, beginning after December 15, 2015. An entity can adopt the guidance prospectively or retrospectively and early adoption is permitted. The Company does not expect that this guidance will have a material impact on its consolidated financial statements. In April 2015, the FASB issued guidance which requires debt issuance costs to be presented in the balance sheet as a direct deduction from the related debt liability rather than an asset. The recognition and measurement guidance for debt issuance costs are not affected by this guidance. This new guidance is effective retrospectively for fiscal years, and interim periods within those years, beginning after December 15, 2015. Early adoption is permitted. The Company will adopt this guidance in the first quarter of 2016. The Company does not expect that this guidance will have a material impact on its consolidated financial statements. In August 2014, the FASB issued guidance which requires management to evaluate whether there is substantial doubt about an entity’s ability to continue as a going concern and to provide disclosure in the footnotes under certain circumstances. This guidance is effective for fiscal years ending after December 15, 2016 with early adoption permitted. The Company does not expect that this guidance will have a material impact on its consolidated financial statements. In May 2014, the FASB issued guidance to provide a single, comprehensive revenue recognition model for all contracts with customers. The new revenue recognition model supersedes existing revenue recognition guidance and requires revenue recognition to depict the transfer of promised goods or services to customers in an amount that reflects the consideration an entity expects to receive in exchange for those goods or services. This guidance is effective for fiscal years and interim periods with those years beginning after December 15, 2017 and early adoption is not permitted. The guidance permits the use of either a full or modified retrospective or cumulative effect transition method. The Company is currently evaluating the impact that the implementation of this standard will have on its consolidated financial statements.

EQUITY INVESTMENT

EQUITY INVESTMENT	12 Months Ended
	Dec. 31, 2015
Equity Method Investments and Joint Ventures [Abstract]
EQUITY INVESTMENT	EQUITY INVESTMENT In December 2015, the Company entered into a subscription agreement with Produquímica Indústria e Comércio S.A., a Brazilian corporation ("Produquímica"), and a sale and purchase agreement with certain of the current shareholders of Produquímica. Pursuant to these agreements, the Company acquired, in the aggregate, 35% of the issued and outstanding capital stock of Produquímica for an aggregate purchase price of R$ 452.4 million , or approximately $114.1 million U.S. dollars at closing. The Company acquired 6% of the common shares at closing and has approximately 29% of preferred shares that will be converted to common shares upon the settlement of certain post-closing adjustments, including possible additional consideration from the Company. The additional consideration will be based upon Produquímica's 2015 adjusted earnings before interest taxes, depreciation and amortization (adjusted "EBITDA"), as defined in the agreements. The Subscription Agreement also contains a put right, allowing the current shareholders to notify the Company of their intent to sell the remainder of their interests in Produquímica to the Company during October of 2016, 2017 and 2018, and a call right, allowing the Company to purchase the remainder of the current shareholders’ interests in Produquímica in October 2018, in each case at the price and on other terms and conditions set forth in the subscription agreement. The exercise price of either the put or call will be based on the adjusted EBITDA for the fiscal year in which the option is exercised and is expected to close after the applicable fiscal year end, subject to regulatory approval. In connection with this transaction, the Company entered into a new U.S. dollar-denominated $100.0 million Term Loan E (the "Term Loan E") with certain existing lenders to fund the acquisition of the 35% equity stake in Produquímica. The Company has recorded a long-term asset for its investment in its consolidated balance sheet of approximately $116.4 million, including the transaction costs of approximately $2.3 million that were directly related to the investment.

GODERICH TORNADO

GODERICH TORNADO	12 Months Ended
	Dec. 31, 2015
Goderich Tornado [Abstract]
GODERICH TORNADO	GODERICH TORNADO In August 2011, a tornado struck the Company’s salt mine and its salt mechanical evaporation plant, both located in Goderich, Ontario. There was no damage to the underground operations at the mine. However, some of the mine’s surface structures and the evaporation plant incurred significant damage which temporarily ceased production at both facilities. Both facilities resumed normal production and shipping activities in 2012. The Company recorded impairment of its property, plant and equipment and clean-up and restoration costs during 2011 through 2013 related to the impacted areas at both of the Goderich facilities. There were no material expenses or charges related to the tornado in 2014. In the third quarter of 2014 , the Company settled its insurance claim related to the tornado. The settlement included a substantial amount related to business interruption losses. Cumulatively, the Company received $114.9 million in cash from 2011 to 2014. In connection with the settlement, the Company released its deferred revenue balance of $83.3 million and recorded a gain of $82.3 million as a reduction to product cost and approximately $1.0 million as a reduction to selling, general and administrative expenses in its consolidated statements of operations for the third quarter of 2014 .

INVENTORIES

INVENTORIES	12 Months Ended
	Dec. 31, 2015
Inventory Disclosure [Abstract]
INVENTORIES	INVENTORIES Inventories consist of the following at December 31 (in millions): 2015 2014 Finished goods $ 223.1 $ 148.5 Raw materials and supplies 52.2 50.5 Total inventories $ 275.3 $ 199.0

PROPERTY PLANT AND EQUIPMENT

PROPERTY PLANT AND EQUIPMENT	12 Months Ended
	Dec. 31, 2015
Property, Plant and Equipment [Abstract]
PROPERTY PLANT AND EQUIPMENT	PROPERTY PLANT AND EQUIPMENT Property, plant and equipment consists of the following at December 31 (in millions): 2015 2014 Land, buildings and structures and leasehold improvements $ 347.3 $ 352.2 Machinery and equipment 701.5 669.1 Office furniture and equipment 25.4 17.5 Mineral interests 169.6 179.6 Construction in progress 191.5 108.9 1,435.3 1,327.3 Less accumulated depreciation and depletion (634.6 ) (626.4 ) Property, plant and equipment, net $ 800.7 $ 700.9

GOODWILL AND OTHER INTANGIBLE A

GOODWILL AND OTHER INTANGIBLE ASSETS	12 Months Ended
	Dec. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
GOODWILL AND OTHER INTANGIBLE ASSETS	GOODWILL AND OTHER INTANGIBLE ASSETS The asset value and accumulated amortization as of December 31, 2015 and December 31, 2014 for the finite-lived intangibles assets are as follows (in millions): Supply Agreement SOP Production Rights Customer/ Distributor Relationships Lease Rights Patents Other Total December 31, 2015 Gross intangible asset $ 26.1 $ 24.3 $ 7.0 $ 1.6 $ 14.9 $ 3.9 $ 77.8 Accumulated amortization (2.6 ) (11.7 ) (2.5 ) (0.2 ) (2.3 ) (1.2 ) (20.5 ) Net intangible assets $ 23.5 $ 12.6 $ 4.5 $ 1.4 $ 12.6 $ 2.7 $ 57.3 Supply Agreement SOP Production Rights Customer Relationships Lease Rights Patents Other Total December 31, 2014 Gross intangible asset $ 31.3 $ 24.3 $ 8.1 $ 1.9 $ 17.9 $ 4.6 $ 88.1 Accumulated amortization (2.5 ) (10.8 ) (2.0 ) (0.2 ) (1.2 ) (0.6 ) (17.3 ) Net intangible assets $ 28.8 $ 13.5 $ 6.1 $ 1.7 $ 16.7 $ 4.0 $ 70.8 The estimated lives of the Company’s intangible assets are as follows: Intangible asset Estimated Lives Supply agreement 50 years SOP production rights 25 years Patents 10-20 years Developed technology 5 years Lease rights 25 years Customer and distributor relationships 10 years Trademarks 10 years Noncompete agreements 5 years Trade names Indefinite Water rights Indefinite None of the finite-lived intangible assets have a residual value. Aggregate amortization expense was $4.4 million in 2015 , $4.3 million in 2014 and $2.0 million in 2013 and is projected to be between $3.5 million and $4.1 million per year over the next five years. The weighted average life for the Company’s finite-lived intangibles is 29 years. In addition, the Company has water rights of $17.7 million and $22.9 million as of December 31, 2015 , and December 31, 2014 , respectively, and trade names of $10.3 million and $12.4 million as of December 31, 2015 , and December 31, 2014 , respectively, which have indefinite lives. In the fourth quarter of 2015, the Company reclassified water rights of $5.2 million as assets held for sale (see Note 2 for more detail). The Company has goodwill of $58.1 million and $68.5 million as of December 31, 2015 , and December 31, 2014 , in its consolidated balance sheets. Approximately $51.7 million and $62.0 million of the amounts recorded for goodwill as of December 31, 2015 , and December 31, 2014 , respectively, were recorded in the Company’s plant nutrition segment and the remaining amounts in both periods were immaterial and recorded in its corporate and other and salt segment. The decrease in the balance of goodwill from December 31, 2014 , was due to the impact from translating foreign denominated amounts to U.S. dollars.

INCOME TAXES

INCOME TAXES	12 Months Ended
	Dec. 31, 2015
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES The Company files U.S., Brazilian, Canadian and U.K. tax returns at the federal and local taxing jurisdictional levels. The Company’s U.S. federal tax returns for tax years 2012 forward remain open and subject to examination. Generally, the Company’s state, local and foreign tax returns for years as early as 2003 forward remain open and subject to examination, depending on the jurisdiction. The following table summarizes the Company’s income tax provision (benefit) related to earnings for the years ended December 31 (in millions): 2015 2014 2013 Current: Federal $ 31.7 $ 37.4 $ 23.2 State 7.3 9.5 5.7 Foreign 16.4 23.4 14.6 Total current 55.4 70.3 43.5 Deferred: Federal (0.2 ) (3.6 ) (2.5 ) State — (0.9 ) (0.6 ) Foreign 0.1 8.1 2.9 Total deferred (0.1 ) 3.6 (0.2 ) Total provision for income taxes $ 55.3 $ 73.9 $ 43.3 The following table summarizes components of earnings before taxes and shows the tax effects of significant adjustments from the expected tax expense computed at the federal statutory rate for the years ended December 31 (in millions): 2015 2014 2013 Domestic income $ 170.6 $ 184.3 $ 112.3 Foreign income 43.9 107.5 61.8 Earnings before income taxes 214.5 291.8 174.1 Computed tax at the U.S. federal statutory rate of 35% 75.1 102.1 60.9 Foreign income rate differential, mining, and withholding taxes, net of U.S. federal deduction (1.2 ) (9.3 ) (2.6 ) Percentage depletion in excess of basis (11.2 ) (11.8 ) (9.0 ) Other domestic tax reserves, net of reversals (4.5 ) (3.9 ) (0.9 ) Domestic manufacturers deduction (2.4 ) (2.5 ) (1.3 ) State income taxes, net of federal income tax benefit 5.1 5.5 3.4 Interest expense recognition differences (6.1 ) (7.1 ) (7.0 ) Other, net 0.5 0.9 (0.2 ) Provision for income taxes $ 55.3 $ 73.9 $ 43.3 Effective tax rate 26 % 25 % 25 % Under U.S. GAAP, deferred tax assets and liabilities are recognized for the estimated future tax effects, based on enacted tax law, of temporary differences between the values of assets and liabilities recorded for financial reporting and tax purposes, and of net operating losses and other carryforwards. The significant components of the Company’s deferred tax assets and liabilities were as follows at December 31 (in millions): 2015 2014 Current deferred tax assets (a) : Accrued expenses $ — $ 3.5 Other, net — 6.2 Current deferred tax assets — 9.7 Current deferred tax liabilities (a) : Other, net — 0.4 Current deferred tax liabilities — 0.4 Noncurrent deferred taxes: Property, plant and equipment 73.0 77.6 Intangible asset 13.9 17.7 Other, net 3.3 2.7 Total noncurrent deferred tax liabilities 90.2 98.0 Deferred tax assets: Net operating loss carryforwards 2.6 0.8 Stock-based compensation 4.7 3.7 Other, net 12.5 5.6 Subtotal 19.8 10.1 Valuation allowance (0.9 ) (1.0 ) Total noncurrent deferred tax assets 18.9 9.1 Net noncurrent deferred tax liabilities $ 71.3 $ 88.9 (a) The Company elected to prospectively adopt guidance from the FASB which requires deferred tax assets and liabilities to be presented as noncurrent in its consolidated balance sheets. This guidance was elected prospectively and the prior period was not retrospectively adjusted (see Recent Accounting Pronouncements in Note 2). At December 31, 2015 , the Company had approximately $3.6 million of gross foreign federal net operating loss ("NOL") carryforwards that have no expiration date, $1.7 million of gross foreign federal NOL carryforwards which expire in 2033 and $0.2 million of net operating tax-effected state NOL carryforwards which expire in 2033 . The Company has recorded a valuation allowance for a portion of its deferred tax asset relating to various tax attributes that it does not believe are, more likely than not to be realized. As of December 31, 2015 and 2014 , the Company’s valuation allowance was $0.9 million and $1.0 million , respectively. In the future, if the Company determines, based on existence of sufficient evidence, that it should realize more or less of its deferred tax assets, an adjustment to the valuation allowance will be made in the period such a determination is made. The calculation of the Company’s tax liabilities involves dealing with uncertainties in the application of complex tax regulations in multiple jurisdictions. The Company recognizes potential liabilities for unrecognized tax benefits in the U.S. and other tax jurisdictions in accordance with applicable U.S. GAAP, which requires uncertain tax positions to be recognized only if they are more likely than not to be upheld based on their technical merits. The measurement of the uncertain tax position is based on the largest benefit amount that is more likely than not (determined on a cumulative probability basis) to be realized upon settlement of the matter. If payment of these amounts ultimately proves to be unnecessary, the reversal of the liabilities would result in tax benefits being recognized in the period when the Company determines the liabilities are no longer necessary. If the Company’s estimate of tax liabilities proves to be less than the ultimate assessment, a further charge to expense may result. The Company’s uncertain tax positions primarily relate to transactions and deductions involving U.S. and Canadian operations. If favorably resolved, $9.3 million of unrecognized tax benefits would decrease the Company’s effective tax rate. Management believes that it is reasonably possible that unrecognized tax benefits will decrease by approximately $0.8 million in the next twelve months largely as a result of tax returns being closed to future audits. In the fourth quarter of 2015 , the Company’s income tax expense included a benefit of approximately $2.7 million related to the release of uncertain tax positions due to the expiration of the statutes of limitations. The following table shows a reconciliation of the beginning and ending amount of unrecognized tax benefits (in millions): 2015 2014 2013 Unrecognized tax benefits: Balance at January 1 $ 21.8 $ 24.6 $ 25.3 Additions resulting from current year tax positions 1.6 1.0 1.0 Additions relating to tax positions taken in prior years 0.8 1.1 — Reductions due to cash payments (0.8 ) (0.3 ) (0.8 ) Reductions relating to tax positions taken in prior years (2.4 ) (1.2 ) (0.9 ) Reductions due to expiration of tax years (2.7 ) (3.4 ) — Balance at December 31 $ 18.3 $ 21.8 $ 24.6 The Company accrues interest and penalties related to its uncertain tax positions within its tax provision. During the years ended December 31, 2015 , 2014 and 2013 , the Company accrued interest and penalties, net of reversals, of $0.2 million , $0.6 million and $0.4 million , respectively. As of December 31, 2015 and 2014 , accrued interest and penalties included in the consolidated balance sheets totaled $4.2 million and $4.1 million , respectively. The Company does not provide U.S. federal income taxes on undistributed earnings of foreign companies that are not currently taxable in the U.S. No undistributed earnings of foreign companies were subject to U.S. income tax in the years ended December 31, 2015 , 2014 and 2013. Total undistributed earnings on which no U.S. federal income tax has been provided were $401.0 million at December 31, 2015 . It is not practicable to estimate the amount of tax that might be payable if some or all of such earnings were to be repatriated, and the amount of foreign tax credits would be available to reduce the resulting U.S. income tax liability. As of December 31, 2015 , the Company had $54.4 million of cash and cash equivalents (in the consolidated balance sheets) that were either held directly or indirectly by foreign subsidiaries. Canadian provincial tax authorities have challenged tax positions claimed by one of the Company’s Canadian subsidiaries and have issued tax reassessments for years 2002 - 2010 . The reassessments are a result of ongoing audits and total approximately $77.7 million , including interest through December 31, 2015 . The Company disputes these reassessments and plans to continue to work with the appropriate authorities in Canada to resolve the dispute. There is a reasonable possibility that the ultimate resolution of this dispute, and any related disputes for other open tax years, may be materially higher or lower than the amounts the Company has reserved for such disputes. In connection with this dispute, local regulations require the Company to post security with the tax authority until the dispute is resolved. The Company has posted collateral in the form of a $49.2 million performance bond. The Company has paid approximately $27.3 million , most of which is recorded in other assets in the consolidated balance sheets, with the remaining balance to be paid after 2015 . In addition, Canadian federal and provincial taxing authorities have reassessed the Company for years 2004 - 2006 , which have been previously settled by agreement among the Company, the Canadian federal taxing authority and the U.S. federal taxing authority. The Company has fully complied with the agreement since entering into it and it believes this action is highly unusual. The Company is seeking to enforce the agreement which provided the basis upon which the returns were previously filed and settled. The total amount of the reassessments, including penalties and interest through December 31, 2015 , related to this matter totals approximately $87.1 million . The Company has posted collateral in the form of an approximately $19.3 million performance bond and $34.7 million in the form of a bank letter guarantee, which is necessary to proceed with future appeals or litigation. The Company received Canadian income tax reassessments for years 2007 - 2008 . The total amount of the reassessments, including penalties and interest through December 31, 2015 , related to this matter is approximately $30.8 million . The Company does not agree with these adjustments and is receiving assistance from the tax jurisdictions for relief from the impact of double taxation as available in the tax treaty between the U.S. and Canada. The Company has filed protective Notices of Objection and has agreed to post collateral of an approximately $8.6 million performance bond and $9.4 million in the form of a bank letter guarantee which is necessary to proceed with future appeals or litigation. Although the outcome of examinations by taxing authorities is uncertain, the Company believes it has adequately reserved for this matter. The Company will be required by the same local regulations to provide security for additional interest on the above disputed amounts and for any future reassessments issued by these Canadian tax authorities in the form of cash, letters of credit, performance bonds, asset liens or other arrangements agreeable with the tax authorities until the dispute is resolved. The Company expects that the ultimate outcome of these matters will not have a material impact on its results of operations or financial condition. However, the Company can provide no assurance as to the ultimate outcome of these matters and the impact could be material if they are not resolved in the Company’s favor. As of December 31, 2015 , the amount reserved related to these reassessments was immaterial to the Company’s consolidated financial statements. Additionally, the Company has other uncertain tax positions as well as assessments and disputed positions with taxing authorities in its various jurisdictions.

PENSION PLANS AND OTHER BENEFIT

PENSION PLANS AND OTHER BENEFITS	12 Months Ended
	Dec. 31, 2015
Compensation and Retirement Disclosure [Abstract]
PENSION PLANS AND OTHER BENEFITS	PENSION PLANS AND OTHER BENEFITS The Company has a defined benefit pension plan for certain of its U.K. employees. Benefits of this plan are based on a combination of years of service and compensation levels. This plan was closed to new participants in 1992 . Beginning December 1, 2008 , future benefits ceased to accrue for the remaining active employee participants in the plan concurrent with the establishment of a defined contribution plan for these employees. The Company’s U.K. pension fund investment strategy is to maximize return on investments while minimizing risk. This is accomplished by investing in high-grade equity and debt securities. The Company’s portfolio guidelines recommend that equity securities comprise approximately 75% of the total portfolio and that approximately 25% be invested in debt securities. In 2014 and 2015 , the Company’s portfolio shifted to a smaller proportion of equity funds due to the increased volatility of these funds over the last several years and it is researching strategies that will reduce volatility, while also maximizing returns. Investment strategies and portfolio allocations are based on the plan’s benefit obligations and its funded or underfunded status, expected returns, and the Company’s portfolio guidelines and are monitored on a regular basis. The weighted-average asset allocations by asset category are as follows: Plan Assets at December 31, Asset Category 2015 2014 Cash and cash equivalents 1 % 1 % Equity funds — % 53 % Blended funds 32 % — % Bond funds 45 % 46 % Insurance policy 22 % — % Total 100 % 100 % The fair value of the Company’s pension plan assets at December 31, 2015 , and 2014 by asset category (see Note 14 for a discussion regarding fair value measurements) are as follows (in millions): Market Value at December 31, 2015 Level One Level Two Level Three Asset category: Cash and cash equivalents (a) $ 0.9 $ 0.9 $ — $ — Equity funds — — — — Blended funds (b) 21.1 — 21.1 — Bond funds (c) : Treasuries 30.3 — 30.3 — Insurance policy (d) 14.6 — — 14.6 Total Pension Assets $ 66.9 $ 0.9 $ 51.4 $ 14.6 (a) The fair value of cash and cash equivalents is its carrying value. (b) The Company is invested in a diversified growth fund. The diversified growth fund is valued at the last traded or official close for the underlying equities and bid or mid for the underlying fixed income securities depending on the portfolio benchmark. Where representative prices are unavailable, underlying fixed income investments are valued based on other observable market-based inputs. (c) This category includes investments in investment-grade fixed-income instruments and funds linked to U.K. treasury notes. The funds are valued using the bid amounts for each fund. All of the Company’s bond fund pension assets are invested in U.K.-linked treasuries as of December 31, 2015 . (d) The insurance policy has been written by an insurance company with an A+ rating from Standard and Poors. The policy derives its value primarily from its underlying investments which consists of separate funds also managed by the underwriter. The policy’s holdings consist primarily of a unit trust fund, which is valued based on its underlying holdings of equities, fixed income securities, cash, and derivative instruments. Those underlying investments are valued at bid price on the last business day of the period when available. Other investments use the last available authorized price of the last business day of the period. Unquoted investments are valued based upon the fund manager’s opinion of fair value based primarily on other observable market-based inputs. Open positions in derivative contracts or foreign currency transactions are included at their mark to market value. Money market instruments are valued based upon amortized cost. Term deposits are valued at their nominal value. Market Value at December 31, 2014 Level One Level Two Level Three Asset category: Cash and cash equivalents (a) $ 1.0 $ 1.0 $ — $ — Equity funds 37.0 — 37.0 — Bond funds (b) : Treasuries 32.3 — 32.3 — Total Pension Assets $ 70.3 $ 1.0 $ 69.3 $ — (a) The fair value of cash and cash equivalents is its carrying value. (b) This category includes investments in investment-grade fixed-income instruments and funds linked to U.K. treasury notes. The funds are valued using the bid amounts for each fund. All of the Company’s bond fund pension assets are invested in U.K.-linked treasuries as of December 31, 2014 . The changes in Level 3 pension plan assets for the year ended December 31, 2015 were as follows (in millions): Year Ended December 31, 2015 Value of Insurance Policy Beginning balance as of January 1, 2015 $ — Purchase 15.4 Unrealized loss (0.1 ) Currency fluctuation adjustment (0.7 ) Ending balance as of December 31, 2015 $ 14.6 As of December 31, 2015 , and 2014 , amounts recognized in accumulated other comprehensive income, net of tax, consisted of actuarial net losses of $3.8 million (including $5.6 million of accumulated loss less prior service cost of $1.8 million ) and $8.9 million (including $10.9 million of accumulated loss less prior service cost of $2.0 million ), respectively. During 2015 , the amounts recognized in accumulated other comprehensive income (loss), net of tax, consisted of actuarial net gains of $3.7 million , amortization of loss of $1.2 million , amortization of prior service cost of $(0.1) million and foreign exchange of $0.4 million . During 2014 , the amounts recognized in accumulated other comprehensive income (loss), net of tax, consisted of actuarial net losses of $(1.6) million , amortization of loss of $1.4 million , amortization of prior service cost of $(0.1) million and foreign exchange of $0.6 million . During 2013 , the amounts recognized in accumulated other comprehensive income (loss), net of tax, consisted of actuarial net losses of $(0.8) million , amortization of loss of $1.5 million , amortization of prior service cost of $(0.1) million and foreign exchange of $(0.2) million . The Company expects to recognize approximately $0.3 million ( $0.4 million of amortization of loss less $0.1 million of prior service cost) of losses from accumulated other comprehensive income as a component of net periodic benefit cost in 2016 . Total net periodic benefit cost (benefit) in 2016 is expected to be $(0.2) million . The assumptions used in determining pension information for the plans for the years ended December 31 were as follows: 2015 2014 2013 Discount rate 3.40 % 4.40 % 4.40 % Expected return on plan assets 4.30 % 5.30 % 4.60 % The overall expected long-term rate of return on plan assets is a weighted-average expectation based on the fair value of targeted and expected portfolio composition. The Company considers historical performance and current benchmarks to arrive at expected long-term rates of return in each asset category. The Company determines its discount rate based on a forward yield curve for a portfolio of high-credit-quality bonds with expected cash flows and an average duration closely matching the expected benefit payments under the plan. The Company’s funding policy is to make the minimum annual contributions required by applicable regulations or agreements with the plan administrator. Management expects total contributions during 2016 will be approximately $1.5 million . In addition, the Company may periodically make contributions to the plan based upon the underfunded status of the plan or other transactions, which warrant incremental contributions in the judgment of management. The U.K. pension plan includes a provision whereby supplemental benefits may be available to participants under certain circumstances after case review and approval by the plan trustees. Because instances of this type of benefit have historically been infrequent, the development of the projected benefit obligation and net periodic pension cost has not provided for any future supplemental benefits. If additional benefits are approved by the trustees, it is likely that an additional contribution would be required and the amount of incremental benefits would be expensed by the Company. The Company expects to pay the following benefit payments (in millions): Calendar Year Future Expected Benefit Payments 2016 $ 2.8 2017 2.9 2018 3.0 2019 3.1 2020 3.2 2021 – 2025 17.4 The following table sets forth pension obligations and plan assets for the Company’s defined benefit plan, as of December 31 (in millions): 2015 2014 Change in benefit obligation: Benefit obligation as of January 1 $ 76.8 $ 73.6 Interest cost 2.5 3.2 Actuarial (gain) loss (5.5 ) 7.6 Benefits paid (2.9 ) (2.9 ) Currency fluctuation adjustment (4.0 ) (4.7 ) Benefit obligation as of December 31 66.9 76.8 Change in plan assets: Fair value as of January 1 70.3 66.7 Actual return 1.9 9.2 Company contributions 1.5 1.6 Currency fluctuation adjustment (3.9 ) (4.3 ) Benefits paid (2.9 ) (2.9 ) Fair value of plan assets as of December 31 66.9 70.3 Underfunded status of the plan $ — $ (6.5 ) The Company's defined benefit plan was adequately funded as of December 31, 2015 and accordingly, an immaterial noncurrent asset has been recorded in the consolidated balance sheets. The underfunded status of the defined pension plan in 2014 , which was recorded in the consolidated balance sheets, included $1.6 million in accrued expenses and $4.9 million in noncurrent liabilities. The accumulated benefit obligation for the defined benefit pension plan was $66.9 million and $76.8 million as of December 31, 2015 and 2014 , respectively. The accumulated benefit obligation was approximately the same as the plan's assets as of December 31, 2015. The accumulated benefit obligation was in excess of the plan’s assets as of December 31, 2014. The vested benefit obligation is the actuarial present value of the vested benefits to which the employee is currently entitled but based on the employee's expected date of retirement. Since all employees are vested, the accumulated benefit obligation and the vested benefit obligation are the same amount. The Company uses a straight-line methodology of amortization subject to a corridor based upon the higher of the fair value of assets and the pension benefit obligation over a five -year period. The components of net pension expense were as follows for the years ended December 31 (in millions): 2015 2014 2013 Interest cost on projected benefit obligation $ 2.5 $ 3.2 $ 3.0 Prior service cost (0.1 ) (0.1 ) (0.1 ) Expected return on plan assets (2.9 ) (3.5 ) (2.8 ) Net amortization 1.5 1.7 1.8 Net pension expense $ 1.0 $ 1.3 $ 1.9 The Company has defined contribution and pre-tax savings plans ("Savings Plans") for certain of its employees. Under each of the Savings Plans, participants are permitted to defer a portion of their compensation. Company contributions to the Savings Plans are based on a percentage of employee contributions. Additionally, certain of the Company’s Savings Plans have a profit sharing feature for salaried and non-union hourly employees. The Company contribution to the profit-sharing feature is based on the employee’s age and pay and the Company’s financial performance. Expense attributable to all Savings Plans was $8.9 million , $11.5 million and $7.6 million for the years ended December 31, 2015 , 2014 and 2013 , respectively. The Savings Plans include a non-qualified plan for certain of its executive officers and key employees who are limited in their ability to participate in qualified plans due to existing regulations. These employees are allowed to defer a portion of their compensation, upon which they will be entitled to receive Company matching contributions as if the limitations imposed by current U.S. regulations for qualified plans were not in place. The Company’s matching contributions are based on a percentage of the employee’s deferred salary, profit sharing contributions and any investment income (loss) that would have been credited to their account had the contributions been made according to employee-designated investment specifications. Although not required to do so, the Company invests amounts equal to the salary deferrals, the corresponding Company match and profit sharing amounts according to the employee-designated investment specifications. As of December 31, 2015 and 2014 , investments in marketable securities totaling $1.6 million and $1.9 million , respectively, were included in other noncurrent assets with a corresponding deferred compensation liability included in other noncurrent liabilities in the consolidated balance sheets. Compensation expense recorded for this plan totaled $0.1 million , $0.1 million and $0.5 million for the years ended December 31, 2015 , 2014 and 2013 , respectively. The total including amounts attributable to investment income was immaterial in 2015, $0.1 million in 2014 and $0.4 million in 2013 , and was included in other, net in the consolidated statements of operations.

LONG TERM DEBT

LONG TERM DEBT	12 Months Ended
	Dec. 31, 2015
Debt Disclosure [Abstract]
LONG TERM DEBT	LONG TERM DEBT The Company amended and restated its senior secured credit facility (the "Credit Agreement") and refinanced its term loans into a single term loan ("Term Loan") in May 2012. In December 2013 , the Company amended and extended its existing $125 million revolving credit facility (the "Revolving Credit Facility") to August 2017 (previously October 2015). In connection with this transaction, the Company paid and capitalized approximately $0.6 million of deferred financing costs. In December 2015, the Company amended its Credit Agreement to enter into a new U.S. dollars denominated $100.0 million Term Loan E with certain existing lenders. The proceeds were used to fund the acquisition of the 35% equity stake in Produquímica. In connection with the Term Loan E transaction, the Company paid and expensed approximately $0.3 million in fees in other expense in its consolidated statements of operations in 2015. The Term Loan and Term Loan E are due in quarterly installments of principal and interest and mature in May 2017. The Term Loan and Term Loan E can be prepaid at any time without penalty. Under the Revolving Credit Facility, $40 million may be drawn in Canadian dollars and $10 million may be drawn in British pounds sterling. Additionally, the Revolving Credit Facility includes a sub-limit for short-term letters of credit in an amount not to exceed $50 million . As of December 31, 2015 , there was $4.5 million outstanding under the Revolving Credit Facility, and, after deducting outstanding letters of credit totaling $5.6 million , the Company’s borrowing availability was $114.9 million . The Company incurs participation fees related to its outstanding letters of credit and commitment fees on its available borrowing capacity. The rates vary depending on the Company’s leverage ratio. Bank fees are not material. Interest on the Company’s Credit Agreement is variable based on either the Eurodollar rate ("LIBOR") or a base rate (defined as the greater of a specified U.S. or Canadian prime lending rate or the federal funds effective rate, increased by 0.5% ) plus a margin, which is dependent upon the Company’s leverage ratio and the type of term loan borrowing. Currently, the Term Loan and the Term Loan E bear interest at 1.75% over LIBOR. As of December 31, 2015 , the weighted average interest rate was 2.1% on all borrowings outstanding under the Credit Agreement. In June 2014, the Company issued 4.875% Senior Notes with an aggregate face amount of $250.0 million due in 2024 which bear interest at a rate of 4.875% per year payable semi-annually in January and July, beginning in January 2015. The 4.875% Senior Notes were issued at their face value. With the proceeds of the 4.875% Senior Notes, the Company redeemed all of its previously outstanding $100.0 million aggregate principal amount of 8% Senior Notes due 2019. In connection with the debt refinancing, the Company incurred approximately $8.1 million of costs, including $4.1 million of fees that were capitalized as deferred financing costs related to the 4.875% Senior Notes and $4.0 million in call premiums. The $4.0 million paid for call premiums along with the write-off of $1.4 million of the Company’s unamortized deferred financing costs and approximately $1.5 million of original issue discount, each related to the 8% Senior Notes, were recorded in other expense in the consolidated statements of operations for 2014 . The Credit Agreement and the indenture governing the 4.875% Senior Notes limit the Company’s ability, among other things, to: incur additional indebtedness or contingent obligations; pay dividends or make distributions to stockholders; repurchase or redeem stock; make investments; grant liens; enter into transactions with stockholders and affiliates; sell assets; and acquire the assets of, or merge or consolidate with, other companies. The Term Loan, Term Loan E and Revolving Credit Facility are secured by substantially all existing and future assets of the Company’s subsidiaries. Additionally, the Credit Agreement requires the Company to maintain certain financial ratios, including a minimum interest coverage ratio and a maximum total leverage ratio. As of December 31, 2015 , the Company was in compliance with each of its covenants. The 4.875% Senior Notes in the table below are subordinate to the Credit Agreement borrowings. Third-party long-term debt consists of the following at December 31 (in millions): 2015 2014 Term Loan due May 2017 $ 472.5 $ 376.4 Revolving Credit Facility due August 2017 4.5 — 4.875% Senior Notes due July 2024 250.0 250.0 727.0 626.4 Less current portion (4.9 ) (3.9 ) Long-term debt $ 722.1 $ 622.5 Future maturities of long-term debt for the years ending December 31, are as follows (in millions): Debt Maturity 2016 $ 4.9 2017 472.1 2018 — 2019 — 2020 — Thereafter 250.0 Total $ 727.0

DERIVATIVES AND FAIR VALUES OF

DERIVATIVES AND FAIR VALUES OF FINANCIAL INSTRUMENTS	12 Months Ended
	Dec. 31, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
DERIVATIVES AND FAIR VALUES OF FINANCIAL INSTRUMENTS	DERIVATIVES AND FAIR VALUES OF FINANCIAL INSTRUMENTS The Company is subject to various types of market risks including interest rate risk, foreign currency exchange rate transaction and translation risk, and commodity pricing risk. Management may take actions to mitigate the exposure to these types of risks, including entering into forward purchase contracts and other financial instruments. Currently, the Company manages a portion of its commodity pricing risk by using derivative instruments. The Company does not seek to engage in trading activities or take speculative positions with any financial instrument arrangements. The Company has entered into natural gas derivative instruments with counterparties it views as creditworthy. However, management does attempt to mitigate its counterparty credit risk exposures by, among other things, entering into master netting agreements with these counterparties. Cash Flow Hedges As of December 31, 2015 , the Company has entered into natural gas derivative instruments. The Company records derivative financial instruments as either assets or liabilities at fair value in the consolidated statements of financial position. Derivatives qualify for treatment as hedges when there is a high correlation between the change in fair value of the derivative instrument and the related change in value of the underlying hedged item. Depending on the exposure being hedged, the Company must designate the hedging instrument as a fair value hedge, a cash flow hedge or a net investment in foreign operations hedge. All derivative instruments held by the Company as of December 31, 2015 , and 2014 qualified as cash flow hedges. For these qualifying hedges, the effective portion of the change in fair value is recognized through earnings when the underlying transaction being hedged affects earnings, allowing a derivative’s gains and losses to offset related results from the hedged item in the statements of operations. For derivative instruments that are not accounted for as hedges, or for the ineffective portions of qualifying hedges, the change in fair value is recorded through earnings in the period of change. Any ineffectiveness related to these hedges was not material for any of the periods presented. Natural gas is consumed at several of the Company’s production facilities, and a change in natural gas prices impacts the Company’s operating margin. As of December 31, 2015 , the Company had entered into natural gas derivative instruments to hedge a portion of its natural gas purchase requirements through December 2017 . The Company’s objective is to reduce the earnings and cash flow impacts of changes in market prices of natural gas by fixing the purchase price of up to 90% of its forecasted natural gas usage. It is the Company’s policy to consider hedging portions of its natural gas usage up to 36 months in advance of the forecasted purchase. As of December 31, 2015 , and 2014 , the Company had agreements in place to hedge forecasted natural gas purchases of 2.8 million and 3.4 million MMBtus, respectively. As of December 31, 2015 , the Company expects to reclassify from accumulated other comprehensive loss to earnings during the next 12 months approximately $2.5 million of net losses on derivative instruments related to its natural gas hedges. The following tables present the fair value of the Company’s hedged items as of December 31, 2015 , and December 31, 2014 (in millions): Asset Derivatives Liability Derivatives Derivatives designated as hedging instruments (a) : Balance Sheet Location December 31, 2015 Balance Sheet Location December 31, 2015 Commodity contracts (b) Other current assets $ 0.1 Accrued expenses $ 2.6 Commodity contracts Other assets — Other noncurrent liabilities 0.1 Total derivatives designated as hedging instruments $ 0.1 $ 2.7 (a) The Company has commodity hedge agreements with two counterparties. Amounts recorded as liabilities for the Company’s commodity contracts are payable to both counterparties. (b) The Company has master netting agreements with its counterparties and accordingly has netted in its consolidated balance sheets approximately $0.1 million of its commodity contracts that are in a receivable position against its contracts in payable positions. Asset Derivatives Liability Derivatives Derivatives designated as hedging instruments (a) : Balance Sheet Location December 31, 2014 Balance Sheet Location December 31, 2014 Commodity contracts (b) Other current assets $ 0.1 Accrued expenses $ 2.5 Commodity contracts Other assets — Other noncurrent liabilities 1.0 Total derivatives designated as hedging instruments $ 0.1 $ 3.5 (a) The Company has commodity hedge agreements with four counterparties. Amounts recorded as liabilities for the Company’s commodity contracts are payable to all counterparties. The amount recorded as an asset is due from two counterparties. (b) The Company has master netting agreements with its counterparties and accordingly has netted in its consolidated balance sheets approximately $0.1 million of its commodity contracts that are in a receivable position against its contracts in payable positions. The following tables present activity related to the Company’s other comprehensive income for the twelve months ended December 31, 2015 and December 31, 2014 (in millions): Twelve Months Ended December 31, 2015 Derivatives in Cash Flow Hedging Relationships Location of Gain (Loss) Reclassified from Accumulated OCI Into Income (Effective Portion) Amount of (Gain) Loss Recognized in OCI on Derivative (Effective Portion) Amount of Gain (Loss) Reclassified from Accumulated OCI Into Income (Effective Portion) Commodity contracts Product cost $ 2.4 $ (3.1 ) Total $ 2.4 $ (3.1 ) Twelve Months Ended December 31, 2014 Derivatives in Cash Flow Hedging Relationships Location of Gain (Loss) Reclassified from Accumulated OCI Into Income (Effective Portion) Amount of (Gain) Loss Recognized in OCI on Derivative (Effective Portion) Amount of Gain (Loss) Reclassified from Accumulated OCI Into Income (Effective Portion) Commodity contracts Product cost $ 2.8 $ 1.0 Total $ 2.8 $ 1.0

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	12 Months Ended
	Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES Contingent Obligations: The Company is involved in proceedings alleging unfair labor practices at its Cote Blanche, Louisiana, mine. This matter arises out of a labor dispute between the Company and the United Steelworkers Union over the terms of a new contract for certain employees at the mine. These employees initiated a strike that began on April 7, 2010, and ended on June 15, 2010. In September 2012, the U.S. National Labor Relations Board issued a decision finding that the Company had committed unfair labor practices in connection with the labor dispute. Under the ruling, the Company is responsible for back pay to affected employees as a result of changes made in union work rules and past practices beginning April 1, 2010. Any requirement for the Company to pay back wages will be offset by any wages earned at other places of employment during this period. In the fourth quarter of 2013, this ruling was upheld by an appeals court and the Company recorded a reserve of $5.0 million in its consolidated financial statements related to expected payments required to resolve the dispute. In the first quarter of 2015, additional information became available and the Company recorded an additional $2.0 million reserve for this matter in its consolidated financial statements. Both parties are currently negotiating in an effort to reach a settlement. If the Company is unable to come to terms with the union, the parties may agree to arbitration and any decisions reached in arbitration would be binding. The Company is currently accrued at the minimum of its estimated range and may need to record additional losses in its financial statements as a result of future developments. The Wisconsin Department of Agriculture, Trade and Consumer Protection ("DATCP") has information indicating that agricultural chemicals are present within the subsurface area of the Kenosha, Wisconsin plant. The agricultural chemicals were used by previous owners and operators of the site. None of the identified chemicals have been used in association with Compass Minerals’ operations since it acquired the property in 2002. DATCP directed the Company to conduct further investigations into the possible presence of agricultural chemicals in soil and ground water at the Kenosha plant. The Company has completed such investigations of the soils and ground water and has provided the findings to DATCP. The Company is presently proceeding with select remediation activities to mitigate agricultural chemical impact to soils and ground water at the site. All investigations and mitigation activities to date, and any potential future remediation work, are being conducted under the Wisconsin Agricultural Chemical Cleanup Program ("ACCP"), which would provide for reimbursement of some of the costs. The Company may seek participation by, or cost reimbursement from, other parties responsible for the presence of any agricultural chemicals found in soil and ground water at this site if the Company does not receive an acknowledgment of no further action and is required to conduct further investigation or remedial work that may not be eligible for reimbursement under the ACCP. The Company is also involved in legal and administrative proceedings and claims of various types from normal Company activities. The Company does not believe that these actions will have a material adverse financial effect on the Company. Furthermore, while any litigation contains an element of uncertainty, management presently believes that the outcome of each such proceeding or claim, which is pending or known to be threatened, or all of them combined, will not have a material adverse effect on the Company’s results of operations, cash flows or financial position. Approximately 30% of the Company’s U.S. workforce and approximately 50% of its global workforce is represented by labor unions. Of the Company’s 12 material collective bargaining agreements, three will expire in 2016 (representing approximately 6% of its total workforce), four will expire in 2017, four will expire in 2018 and one will expire in 2019. Approximately 10% of the Company’s workforce is employed in Europe where trade union membership is common. The Company considers its overall labor relations to be good. Commitments: Leases: The Company leases certain property and equipment under non-cancelable operating leases for varying periods. The aggregate future minimum annual rentals under lease arrangements as of December 31, 2015 , are as follows (in millions): Operating Leases 2016 $ 15.7 2017 9.7 2018 4.1 2019 3.6 2020 1.9 Thereafter 5.0 Total $ 40.0 Rental expense, net of sublease income, was $20.7 million , $18.6 million and $17.1 million for the years ended December 31, 2015 , 2014 and 2013 , respectively. Royalties: The Company has various private, state and Canadian provincial leases associated with the salt and specialty potash businesses, most of which are renewable by the Company. Many of these leases provide for a royalty payment to the lessor based on a specific amount per ton of mineral extracted or as a percentage of revenue. Royalty expense related to these leases was $14.0 million , $17.8 million and $14.7 million for the years ended December 31, 2015 , 2014 and 2013 . Sales Contracts: The Company has various salt and other deicing product sales contracts that include performance provisions governing delivery and product quality. These sales contracts either require the Company to maintain performance bonds for stipulated amounts or contain contractual penalty provisions in the event of non-performance. For the three years ended December 31, 2015 , the Company has had no material penalties related to these sales contracts. At December 31, 2015 , the Company had approximately $106.7 million of outstanding performance bonds, which includes the bonds outstanding for the Company’s tax reassessments, and approximately $44.1 million for bank letter guarantees. Purchase Commitments: In connection with the operations of the Company’s facilities, the Company purchases electricity, other raw materials and services from third parties under contracts extending, in some cases, for multiple years. Purchases under these contracts are generally based on prevailing market prices. The Company has purchase contracts with suppliers for salt and KCl. Additionally, the Company has minimum throughput contracts with some of its depots. The purchase commitments for these contracts are estimated to be approximately $57.6 million for 2016 and between $32.5 million and $35.0 million annually from 2017 through 2020.

STOCKHOLDERS' EQUITY AND EQUITY

STOCKHOLDERS' EQUITY AND EQUITY INSTRUMENTS	12 Months Ended
	Dec. 31, 2015
Stockholders' Equity and Equity Instruments [Abstract]
STOCKHOLDERS' EQUITY AND EQUITY INSTRUMENTS	STOCKHOLDERS’ EQUITY AND EQUITY INSTRUMENTS The Company paid dividends of $2.64 per share in 2015 and currently intends to continue paying quarterly cash dividends. The declaration and payment of future dividends to holders of the Company’s common stock will be at the discretion of its board of directors and will depend upon many factors, including the Company’s financial condition, earnings, legal requirements, restrictions in its debt agreements (see Note 10) and other factors its board of directors deems relevant. Under the Compass Minerals International, Inc. Directors' Deferred Compensation Plan as amended, adopted effective October 1, 2004, the prior equity compensation plan ("2005 Plan") and the current incentive compensation plan ("2015 Plan"), non-employee directors may defer all or a portion of the fees payable for their service, which deferred fees are converted into units equivalent to the value of the Company's common stock. Additionally, as dividends are declared on the Company’s common stock, these units are entitled to accrete dividends in the form of additional units based on the stock price on the dividend payment date. Accumulated deferred units are distributed in the form of Company common stock at a future specified date or following resignation from the board of directors, based upon the member’s annual election. During the years ended December 31, 2015 , 2014 and 2013 , members of the board were credited with 12,542 , 14,340 and 16,331 deferred stock units, respectively. During the years ended December 31, 2015 , 2014 and 2013 , 31,954 , 976 and 1,259 shares of common stock, respectively, were issued from treasury shares for director compensation. Preferred stock The Company is authorized to issue up to 10,000,000 shares of preferred stock, of which no shares are currently issued or outstanding. Of those, 200,000 shares of preferred stock were designated as series A junior participating preferred stock in connection with the Company’s now expired rights agreement. Equity Compensation Awards In 2005, the Company adopted the 2005 Plan for executive officers, other key employees and directors allowing grants of equity instruments, including restricted stock units ("RSUs"), performance stock units ("PSUs") and stock options, with respect to 3,240,000 shares of CMP common stock. In May 2015, the Company’s shareholders approved the 2015 Plan, which authorizes the issuance of 3,000,000 shares. Since the date the 2015 Plan was approved, the Company ceased issuing equity awards under the 2005 Incentive Award Plan. The 2005 and 2015 Plans allow for grants of equity awards to executive officers, other key employees and directors. The grants occur following formal approval by the board of directors or on the date of hire if granted to a new employee, with the amount and terms communicated to employees shortly thereafter. The strike price of options is equal to the closing stock price on the day of grant. In 2015, no options or PSUs were granted under the 2015 Plan. Substantially all of the RSUs granted under both the 2005 and 2015 Plans vest after three years of service entitling the holders to one share of common stock for each vested RSU. The unvested RSUs do not have voting rights but are entitled to receive non-forfeitable dividends (after a performance hurdle has been satisfied in the year of the grant) or other distributions that may be declared on the Company’s common stock equal to the per-share dividend declared. PSUs granted under the 2005 Plan vest after three years of service. The PSUs granted in 2015 have a three -year performance period beginning in 2015 and ending in 2017 and earn between 0% and 200% based upon the attainment of certain performance conditions. The Company granted two types of PSUs in 2015 under the 2005 Plan. The total shareholder return PSU ("TSR PSU") is earned by determining the Company’s total shareholder return, compared to the total shareholder return for each company comprising the Russell 3000 Index over the three -year performance period. The return on invested capital PSU ("ROIC PSU") is earned by averaging the Company’s annual return on invested capital over the three -year performance period. The PSUs granted entitle the holders to receive non-forfeitable dividends or other distributions equal to those declared on the Company’s common stock from the grant date through the vest date for PSUs earned. Stock options granted under the 2005 Plan generally vest ratably, in tranches, over a four -year service period. Unexercised options expire after seven years. Upon vesting, each option can be exercised to purchase one share of the Company’s common stock. The options granted do not participate in dividends and have no voting rights. The exercise price of options is equal to the closing stock price on the day of grant. The following is a summary of CMP’s stock option, RSU and PSU activity and related information for the following periods: Stock Options RSUs PSUs Number Weighted-average exercise price Number Weighted-average fair value Number Weighted-average fair value Outstanding at December 31, 2012 435,721 $ 67.46 77,749 $ 78.46 49,932 $ 83.58 Granted 124,370 76.84 65,521 74.99 29,134 78.01 Exercised (a) (174,149 ) 60.71 — — — — Released from restriction (a) — — (22,658 ) 78.46 (6,341 ) 86.51 Cancelled/Expired (57,578 ) 77.19 (24,894 ) 78.42 (17,576 ) 81.72 Outstanding at December 31, 2013 328,364 $ 72.88 95,718 $ 76.09 55,149 $ 80.89 Granted 95,610 87.18 20,268 86.74 27,574 105.77 Exercised (a) (112,005 ) 67.35 — — — — Released from restriction (a) — — (15,636 ) 86.48 (3,998 ) 93.82 Cancelled/Expired (33,540 ) 79.81 (11,818 ) 76.95 (19,098 ) 89.77 Outstanding at December 31, 2014 278,429 $ 79.23 88,532 $ 76.58 59,627 $ 88.69 Granted 120,956 91.76 21,317 90.94 35,584 100.49 Exercised (a) (33,906 ) 72.53 — — — — Released from restriction (a) — — (15,952 ) 71.69 (10,454 ) 74.49 Cancelled/Expired (b) (12,392 ) 84.71 (2,889 ) 81.43 (7,392 ) 82.46 Outstanding at December 31, 2015 353,087 $ 83.94 91,008 $ 80.65 77,365 $ 96.63 (a) Common stock issued for exercised options and RSUs and PSUs released from restriction were issued from treasury shares. (b) The performance period for the 2013 PSU grant was completed in 2015 . The Company expects to issue 9,914 shares in March 2016 when the 2013 PSU grant vests. The Company generally expenses the fair value of its awards over the vesting period using the straight line method. To estimate the fair value of performance stock units on the grant date, the Company uses a Monte-Carlo simulation model , which simulates the Company’s future stock prices as well as the companies comprising the Russell 3000 Index. This model uses historical stock prices to estimate expected volatility and the Company’s correlation to the applicable index. The risk free rate was determined using the same methodology as the option valuations as discussed below. To estimate the fair value of options on the day of grant, the Company uses the Black-Scholes option valuation model . Award recipients are grouped according to expected exercise behavior. Unless better information is available to estimate the expected term of the options, the estimate is based on historical exercise experience. The risk-free rate, using U.S. Treasury yield curves in effect at the time of grant, is selected based on the expected term of each group. CMP’s historical stock price is used to estimate expected volatility. The weighted average assumptions and fair values for options granted for each of the years ended December 31 is included in the following table. 2015 2014 2013 Fair value of options granted $ 14.78 $ 15.25 $ 19.06 Expected term (years) 4.8 4.8 4.7 Expected volatility 24.9 % 27.8 % 38.0 % Dividend yield 3.1 % 3.4 % 3.0 % Risk-free interest rates 1.6 % 1.5 % 0.9 % As of December 31, 2014 , there were 278,429 options outstanding of which 99,425 were exercisable. The following table summarizes information about options outstanding and exercisable at December 31, 2015 . Options Outstanding Options Exercisable Range of exercise prices Options outstanding Weighted-average remaining contractual life (years) Weighted-average exercise price of options outstanding Options exercisable Weighted-average remaining contractual life (years) Weighted-average exercise price of exercisable options $58.99 - $77.75 114,116 3.7 $ 74.16 63,633 3.3 $ 72.74 $77.76 - $86.99 42,130 1.7 82.51 42,130 1.7 82.51 $87.00 - $89.47 79,717 5.2 87.18 18,445 5.2 87.18 $89.48 - $93.26 117,124 6.2 91.77 74 6.2 91.75 Totals 353,087 4.6 $ 83.94 124,282 3.1 $ 78.21 During the years ended December 31, 2015 , 2014 and 2013 , the Company recorded compensation expense of $6.1 million , $4.9 million and $5.1 million , respectively, related to its stock-based compensation awards that are expected to vest. No amounts have been capitalized. The fair value of options vested was approximately $1.1 million , $1.3 million and $1.6 million in 2015 , 2014 and 2013 , respectively. As of December 31, 2015 , unrecorded compensation cost related to non-vested awards of $6.6 million is expected to be recognized from 2016 through 2019, with a weighted average period of 2.0 years. The intrinsic value of stock options exercised during the twelve months ended December 31, 2015 , 2014 and 2013 totaled approximately $0.6 million , $2.3 million and $4.5 million , respectively. As of December 31, 2015 , the intrinsic value of options outstanding totaled approximately $0.2 million , of which 124,282 options with an intrinsic value of $0.2 million were exercisable. The number of shares held in treasury is sufficient to cover all outstanding equity awards as of December 31, 2015 . Accumulated Other Comprehensive Income (Loss) The Company’s comprehensive income (loss) is comprised of net earnings, net amortization of the unrealized loss of the pension obligation, the change in the unrealized gain (loss) on natural gas cash flow hedges and foreign currency translation adjustments. The components of and changes in accumulated other comprehensive income (loss) ("AOCI") for the twelve months ended December 31, 2015 and 2014 are as follows (in millions): Twelve Months Ended December 31, 2015 (a) Gains and (Losses) on Cash Flow Hedges Defined Benefit Pension Foreign Currency Total Beginning balance $ (2.0 ) $ (9.0 ) $ (4.5 ) $ (15.5 ) Other comprehensive income (loss) before reclassifications (1.5 ) 4.1 (98.4 ) (95.8 ) Amounts reclassified from accumulated other comprehensive loss 1.9 1.1 — 3.0 Net current period other comprehensive income (loss) 0.4 5.2 (98.4 ) (92.8 ) Ending balance $ (1.6 ) $ (3.8 ) $ (102.9 ) $ (108.3 ) (a) With the exception of the cumulative foreign currency translation adjustment, for which no tax effect is recorded, the changes in the components of accumulated other comprehensive gain (loss) presented in the table are reflected net of applicable income taxes. Twelve Months Ended December 31, 2014 (a) Gains and (Losses) on Cash Flow Hedges Defined Benefit Pension Foreign Currency Total Beginning balance $ 0.3 $ (9.3 ) $ 43.5 $ 34.5 Other comprehensive income (loss) before reclassifications (1.7 ) (1.0 ) (48.0 ) (50.7 ) Amounts reclassified from accumulated other comprehensive loss (0.6 ) 1.3 — 0.7 Net current period other comprehensive income (loss) (2.3 ) 0.3 (48.0 ) (50.0 ) Ending balance $ (2.0 ) $ (9.0 ) $ (4.5 ) $ (15.5 ) (a) With the exception of the cumulative foreign currency translation adjustment, for which no tax effect is recorded, the changes in the components of accumulated other comprehensive gain (loss) presented in the table are reflected net of applicable income taxes. Amount Reclassified from AOCI Twelve Months Ended December 31, 2015 Line Item Impacted in the Consolidated Statement of Operations Gains and (losses) on cash flow hedges: Natural gas instruments $ 3.1 Product cost (1.2 ) Income tax expense (benefit) 1.9 Amortization of defined benefit pension: Amortization of loss $ 1.4 Product cost (0.3 ) Income tax expense (benefit) 1.1 Total reclassifications, net of income taxes $ 3.0 Amount Reclassified from AOCI Twelve Months Ended December 31, 2014 Line Item Impacted in the Consolidated Statement of Operations Gains and (losses) on cash flow hedges: Natural gas instruments $ (1.0 ) Product cost 0.4 Income tax expense (benefit) (0.6 ) Amortization of defined benefit pension: Amortization of loss $ 1.6 Product cost (0.3 ) Income tax expense (benefit) 1.3 Total reclassifications, net of income taxes $ 0.7

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS	12 Months Ended
	Dec. 31, 2015
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS	FAIR VALUE MEASUREMENTS As required, the Company’s financial instruments are measured and reported at their estimated fair value. Fair value is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction. When available, the Company uses quoted prices in active markets to determine the fair values for its financial instruments (level one inputs), or absent quoted market prices, observable market-corroborated inputs over the term of the financial instruments (level two inputs). The Company does not have any unobservable inputs that are not corroborated by market inputs (level three inputs) except as stated in Note 9. The Company holds marketable securities associated with its non-qualified savings plan, which are valued based on readily available quoted market prices. The Company utilizes derivative instruments to manage its risk of changes in natural gas prices (see Note 11). The fair value of the natural gas derivative instruments are determined using market data of forward prices for all of the Company’s contracts. The estimated fair values for each type of instrument are presented below (in millions). December 31, 2015 Level One Level Two Level Three Asset Class: Mutual fund investments in a non-qualified savings plan (a) $ 1.6 $ 1.6 $ — $ — Total Assets $ 1.6 $ 1.6 $ — $ — Liability Class: Liabilities related to non-qualified savings plan $ (1.6 ) $ (1.6 ) $ — $ — Derivatives – natural gas instruments (2.6 ) — (2.6 ) — Total Liabilities $ (4.2 ) $ (1.6 ) $ (2.6 ) $ — (a) Includes mutual fund investments of approximately 20% in the common stock of large-cap U.S. companies, approximately 5% in the common stock of small to mid-cap U.S. companies, approximately 5% in the common stock of international companies, approximately 5% in bond funds, approximately 35% in short-term investments and approximately 30% in blended funds. December 31, 2014 Level One Level Two Level Three Asset Class: Mutual fund investments in a non-qualified savings plan (a) $ 1.9 $ 1.9 $ — $ — Total Assets $ 1.9 $ 1.9 $ — $ — Liability Class: Liabilities related to non-qualified savings plan $ (1.9 ) $ (1.9 ) $ — $ — Derivatives – natural gas instruments (3.4 ) — (3.4 ) — Total Liabilities $ (5.3 ) $ (1.9 ) $ (3.4 ) $ — (a) Includes mutual fund investments of approximately 15% in the common stock of large-cap U.S. companies, approximately 5% in the common stock of international companies, approximately 5% in bond funds, approximately 35% in short-term investments and approximately 40% in blended funds. Cash and cash equivalents, accounts receivable (net of reserve for bad debts) and payables are carried at cost, which approximates fair value due to their liquid and short-term nature. The Company’s investments related to its nonqualified retirement plan of $1.6 million and $1.9 million as of December 31, 2015 and December 31, 2014 , respectively, are stated at fair value based on quoted market prices. As of December 31, 2015 , the estimated fair value of the fixed-rate 4.875% Senior Notes, based on available trading information, totaled $237.7 million (level 2) compared with the aggregate principal amount at maturity of $250.0 million . The fair value at December 31, 2015 of amounts outstanding under the Credit Agreement, based upon available bid information received from the Company’s lender, totaled approximately $472.2 million (level 2), compared with the aggregate principal amount at maturity of $477.0 million . The fair value of the Company’s natural gas contracts is based on prices for notional amounts maturing in each respective timeframe.

OPERATING SEGMENTS

OPERATING SEGMENTS	12 Months Ended
	Dec. 31, 2015
Segment Reporting [Abstract]
OPERATING SEGMENTS	OPERATING SEGMENTS The Company’s reportable segments are strategic business units that offer different products and services. They are managed separately because each business requires different technology and marketing strategies. The Company has two reportable segments: salt and plant nutrition. The salt segment produces and markets salt and magnesium chloride for use in road deicing and dust control, food processing, water softeners, and agricultural and industrial applications. SOP crop nutrients, industrial-grade SOP, micronutrients and magnesium chloride for agricultural purposes are produced and marketed through the plant nutrition segment. The accounting policies of the segments are the same as those described in the summary of significant accounting policies. All intersegment sales prices are market-based. The Company evaluates performance based on the operating earnings of the respective segments. Segment information as of and for the years ended December 31, is as follows (in millions): 2015 Salt Plant Nutrition Corporate & Other (a) Total Sales to external customers $ 849.0 $ 238.4 $ 11.3 $ 1,098.7 Intersegment sales 0.1 7.7 (7.8 ) — Shipping and handling cost 239.1 22.4 — 261.5 Operating earnings (loss) 215.2 57.9 (51.7 ) 221.4 Depreciation, depletion and amortization 43.9 29.8 4.6 78.3 Total assets (b) 896.5 679.7 52.7 1,628.9 Capital expenditures 106.5 92.8 18.3 217.6 2014 Salt Plant Nutrition Corporate & Other (a) Total Sales to external customers $ 1,002.6 $ 270.2 $ 9.7 $ 1,282.5 Intersegment sales 0.9 7.1 (8.0 ) — Shipping and handling cost 309.3 28.4 — 337.7 Operating earnings (loss) (c) 291.4 74.8 (55.2 ) 311.0 Depreciation, depletion and amortization 44.8 27.3 5.9 78.0 Total assets 1,045.2 536.2 55.8 1,637.2 Capital expenditures 67.9 42.1 15.2 125.2 2013 Salt Plant Nutrition Corporate & Other (a) Total Sales to external customers $ 920.5 $ 198.6 $ 10.5 $ 1,129.6 Intersegment sales 0.9 7.2 (8.1 ) — Shipping and handling cost 280.7 21.0 — 301.7 Operating earnings (loss) (b) 181.3 58.7 (54.4 ) 185.6 Depreciation, depletion and amortization 45.1 23.8 4.1 73.0 Total assets 942.2 386.8 75.8 1,404.8 Capital expenditures (d) 79.8 38.8 4.1 122.7 (a) Corporate and Other includes corporate entities, records management operations and other incidental operations and eliminations. Operating earnings (loss) for corporate and other includes indirect corporate overhead including costs for general corporate governance and oversight, as well as costs for the human resources, information technology and finance functions. In 2014 , the operating earnings loss includes costs of approximately $4.2 million to consolidate its records management locations by closing one location in London, England. (b) In 2015, the Company's equity investment in Produquímica is included in total assets for its plant nutrition segment. In addition, the Company's assets held for sale have been presented in corporate and other. Total assets in 2015 for both operating segments were negatively impacted by the impact of translating our foreign-denominated assets into U.S. dollars. (c) In 2014 , the Company recorded a gain of $82.3 million in the salt segment and $1.0 million in corporate and other resulting from an insurance settlement related to a tornado at its salt facilities in Goderich, Ontario in August 2011. In the fourth quarter of 2013 , the Company recognized a gain of $9 million in its plant nutrition segment from the settlement of an insurance claim resulting from a loss of mineral-concentrated brine due to an asset failure at its solar evaporation ponds in 2010 and a charge of $4.7 million in its salt segment from a ruling against the Company related to a labor matter. (d) The salt segment includes approximately $15 million of capital expenditures during 2013 to replace and, in some instances, improve property, plant and equipment damaged or destroyed by the tornado at the Company’s Goderich, Ontario facilities in 2011. Financial information relating to the Company’s operations by geographic area for the years ended December 31 is as follows (in millions): Sales 2015 2014 2013 United States (a) $ 834.6 $ 975.2 $ 774.3 Canada 198.4 260.0 256.7 United Kingdom 56.8 41.2 87.1 Other 8.9 6.1 11.5 Total sales $ 1,098.7 $ 1,282.5 $ 1,129.6 (a) United States sales exclude product sold to foreign customers at U.S. ports. Financial information relating to the Company’s long-lived assets, including deferred financing costs and other long-lived assets but excluding the investments related to the nonqualified retirement plan, by geographic area as of December 31 (in millions): Long-Lived Assets 2015 2014 United States $ 502.1 $ 420.0 Canada 394.3 413.7 United Kingdom 95.7 92.3 Brazil 116.4 — Other 6.5 6.6 Total long-lived assets $ 1,115.0 $ 932.6

EARNINGS PER SHARE

EARNINGS PER SHARE	12 Months Ended
	Dec. 31, 2015
Earnings Per Share [Abstract]
EARNINGS PER SHARE	EARNINGS PER SHARE The two-class method requires allocating the Company’s net earnings to both common shares and participating securities. The following table sets forth the computation of basic and diluted earnings per common share (in millions, except for share and per share data): Year ended December 31, 2015 2014 2013 Numerator: Net earnings $ 159.2 $ 217.9 $ 130.8 Less: Net earnings allocated to participating securities (a) (1.0 ) (1.5 ) (1.0 ) Net earnings available to common shareholders $ 158.2 $ 216.4 $ 129.8 Denominator (in thousands): Weighted average common shares outstanding, shares for basic earnings per share (b) 33,677 33,557 33,403 Weighted average equity awards outstanding 15 24 17 Shares for diluted earnings per share 33,692 33,581 33,420 Net earnings per common share, basic $ 4.70 $ 6.45 $ 3.89 Net earnings per common share, diluted $ 4.69 $ 6.44 $ 3.88 (a) Participating securities include options, PSUs and RSUs that receive non-forfeitable dividends. Net earnings were allocated to participating securities of 198,000 , 227,000 and 250,000 for 2015 , 2014 and 2013 , respectively. (b) For the calculation of diluted earnings per share, the Company uses the more dilutive of either the treasury stock method or the two-class method, to determine the weighted average number of outstanding common shares. In addition, the Company had 432,000 , 381,000 and 455,000 weighted options outstanding for 2015 , 2014 and 2013 , respectively, which were anti-dilutive and therefore not included in the diluted earnings per share calculation.

QUARTERLY RESULTS (Unaudited)

QUARTERLY RESULTS (Unaudited)	12 Months Ended
	Dec. 31, 2015
Quarterly Financial Data [Abstract]
QUARTERLY RESULTS (Unaudited)	QUARTERLY RESULTS (Unaudited) (in millions, except share and per share data) Quarter First Second Third Fourth 2015 Sales $ 393.0 $ 183.7 $ 232.7 $ 289.3 Gross profit 113.2 50.6 68.0 98.3 Net earnings 60.6 13.2 27.0 58.4 Net earnings per share, basic 1.79 0.39 0.80 1.72 Net earnings per share, diluted 1.79 0.39 0.80 1.72 Basic weighted-average shares outstanding (in thousands) 33,626 33,682 33,696 33,701 Diluted weighted-average shares outstanding (in thousands) 33,649 33,701 33,708 33,714 2014 Sales $ 422.0 $ 186.6 $ 240.5 $ 433.4 Gross profit (a) 92.3 37.5 149.8 141.8 Net earnings (loss) (a) 50.2 (0.7 ) 87.9 80.5 Net earnings (loss) per share, basic 1.49 (0.02 ) 2.60 2.38 Net earnings (loss) per share, diluted 1.49 (0.02 ) 2.60 2.38 Basic weighted-average shares outstanding (in thousands) 33,502 33,549 33,575 33,600 Diluted weighted-average shares outstanding (in thousands) 33,520 33,549 33,601 33,617 (a) In the third quarter of 2014 , the Company recognized a gain of $83.3 million ( $60.6 million , net of taxes) from an insurance settlement relating to damage it sustained as a result of a tornado that struck its rock salt mine and evaporation plan in Goderich, Ontario, in 2011. The Company recognized $82.3 million of the gain in product cost and $1.0 million of the gain in selling, general and administrative expenses in the consolidated statements of operations. In the second quarter of 2014 , the Company incurred costs of $6.9 million ( $5.1 million , net of taxes) related to the refinancing of its 8% Senior Notes with 4.875% Senior Notes.

SUBSEQUENT EVENT

SUBSEQUENT EVENT	12 Months Ended
	Dec. 31, 2015
Subsequent Events [Abstract]
SUBSEQUENT EVENT	SUBSEQUENT EVENT Dividend Declared: On February 4, 2016 , the board of directors declared a quarterly cash dividend of $0.695 per share on the Company’s outstanding common stock, an increase of 5% from the quarterly cash dividends paid in 2015 of $0.66 per share. The dividend will be paid on March 15, 2016 , to stockholders of record as of the close of business on February 29, 2016 . Restructuring: In February 2016, the Company announced steps to align its inventories with market demand and is undergoing a thorough review of its cost structure. This effort is expected to result in a restructuring charge in the first quarter of 2016 of approximately $4 million , or $0.07 per diluted share, related to a workforce reduction of 150 positions. A significant portion of this total results from the Company's investment in continuous mining at its Goderich, Ontario location. The Company expects that the majority of the workforce reduction to be completed by the end of 2016.

Schedule II Valuation Reserves

Schedule II Valuation Reserves	12 Months Ended
	Dec. 31, 2015
Valuation and Qualifying Accounts [Abstract]
Schedule II - Valuation Reserves	Schedule II — Valuation Reserves Compass Minerals International, Inc. December 31, 2015, 2014 and 2013 Description (in millions) Balance at the Beginning of the Year Additions (Deductions) Charged to Expense Deductions (1) Balance at the End of the Year Deducted from Receivables — Allowance for Doubtful Accounts 2015 $ 1.4 $ 0.6 $ (0.7 ) $ 1.3 2014 1.6 0.3 (0.5 ) 1.4 2013 2.4 0.7 (1.5 ) 1.6 Deducted from Deferred Income Taxes — Valuation Allowance 2015 $ 1.0 $ 0.1 $ (0.2 ) $ 0.9 2014 1.1 0.2 (0.3 ) 1.0 2013 1.3 — (0.2 ) 1.1 (1) Deduction for purposes for which reserve was created.

SUMMARY OF SIGNIFICANT ACCOUN28

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	12 Months Ended
	Dec. 31, 2015
Accounting Policies [Abstract]
Management Estimates	Management Estimates: The preparation of financial statements in conformity with U.S. generally accepted accounting principles ("GAAP") as included in the Accounting Standards Codification requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Actual results could differ from those estimates.
Basis of Consolidation	Basis of Consolidation: The Company’s consolidated financial statements include the accounts of Compass Minerals International, Inc. and its wholly owned domestic and foreign subsidiaries. All significant intercompany balances and transactions have been eliminated in consolidation.
Foreign Currency	Foreign Currency: Assets and liabilities are translated into U.S. dollars at end of period exchange rates. Revenues and expenses are translated using the monthly average rates of exchange during the year. Adjustments resulting from the translation of foreign-currency financial statements into the reporting currency, U.S. dollars, are included in accumulated other comprehensive income (loss). The Company recorded foreign exchange losses of approximately $(33.7) million , $(18.4) million and $(15.0) million in 2015 , 2014 and 2013 , respectively, in accumulated other comprehensive income (loss) related to intercompany notes which were deemed to be of long-term investment nature. Aggregate exchange gains (losses) from transactions denominated in a currency other than the functional currency, which are included in other income, for the years ended December 31, 2015 , 2014 and 2013 , were $13.9 million , $6.6 million and $4.9 million , respectively.
Revenue Recognition	Revenue Recognition: The Company typically recognizes revenue at the time of shipment to the customer, which coincides with the transfer of title and risk of ownership to the customer. Sales represent billings to customers net of sales taxes charged for the sale of the product. Sales include amounts charged to customers for shipping and handling costs, which are expensed when the related product is sold.
Cash and Cash Equivalents	Cash and Cash Equivalents: The Company considers all investments with original maturities of three months or less to be cash equivalents. The Company maintains the majority of its cash in bank deposit accounts with several commercial banks with high credit ratings in the U.S., Canada and Europe. Typically, the Company has bank deposits in excess of federally insured limits. Currently, the Company does not believe it is exposed to significant credit risk on its cash and cash equivalents.
Accounts Receivable and Allowance for Doubtful Accounts	Accounts Receivable and Allowance for Doubtful Accounts: Receivables consist almost entirely of trade accounts receivable. Trade accounts receivable are recorded at the invoiced amount and do not bear interest. The allowance for doubtful accounts is the Company’s best estimate of the amount of probable credit losses in its existing accounts receivable. The Company determines the allowance based on historical write-off experience by business line and a current assessment of its portfolio. The Company reviews its past due account balances for collectability and adjusts its allowance for doubtful accounts accordingly. Account balances are charged off against the allowance when the Company believes it is probable that the receivable will not be recovered.
Inventories	Inventories: Inventories are stated at the lower of cost or market. Finished goods and raw material and supply costs are valued using the average cost method. Raw materials and supplies primarily consist of raw materials purchased to aid in the production of mineral products, maintenance materials and packaging materials. Finished goods are primarily comprised of salt, magnesium chloride and plant nutrition products readily available for sale. Substantially all costs associated with the production of finished goods at the Company’s producing locations are captured as inventory costs. As required by U.S. GAAP, a portion of the fixed costs at a location are not included in inventory and are expensed as a product cost if production at that location is determined to be abnormally low in any period. Additionally, since the Company’s products are often stored at third-party warehousing locations, the Company includes in the cost of inventory the freight and handling costs necessary to move the product to storage until the product is sold to a customer.
Other Current Assets	Other Current Assets: In the fourth quarter of 2015, the Company began marketing assets it held which were used for farming. The Company intends to sell these assets in 2016. The Company has performed an impairment analysis and concluded that the fair market value of these assets exceeds their carrying value. These assets have been recorded at the lower of cost or market less selling costs in other current assets as of December 31, 2015. The amounts classified as held for sale include inventory of approximately $2.7 million , property, plant and equipment of approximately $2.8 million and water rights of approximately $5.2 million . The remaining amounts as of December 31, 2015, and the amounts recorded as of December 31, 2014, consist principally of prepaid expenses.
Property, Plant and Equipment	Property, Plant and Equipment: Property, plant and equipment is stated at cost and includes capitalized interest. The costs of replacements or renewals, which improve or extend the life of existing property, are capitalized. Maintenance and repairs are expensed as incurred. Upon retirement or disposition of an asset, any resulting gain or loss is included in the Company’s operating results. Property, plant and equipment also includes mineral interests. The mineral interests for the Company’s Winsford U.K. mine are owned. The Company leases probable mineral reserves at its Cote Blanche and Goderich mines, its Ogden facility and several of its other facilities. These leases have varying terms, and many provide for a royalty payment to the lessor based on a specific amount per ton of mineral extracted or as a percentage of revenue. The Company’s rights to extract minerals are contractually limited by time. The Cote Blanche mine is operated under land and mineral leases. The mineral lease for the Cote Blanche mine expires in 2060 with two additional 25 -year renewal periods. The Goderich mine mineral reserve lease expires in 2022 with our option to renew until 2043 after demonstrating to the lessor that the mine’s useful life is greater than the lease’s term. The Ogden facility mineral reserve lease renews annually. The Company believes it will be able to continue to extend lease agreements as it has in the past, at commercially reasonable terms, without incurring substantial costs or material modifications to the existing lease terms and conditions, and therefore, management believes that assigned lives are appropriate. The Company’s leased mineral interests are primarily depleted on a units-of-production basis over the respective estimated lives of mineral deposits not to exceed 99 years. The weighted average amortization period for these probable mineral reserves is 81 years as of December 31, 2015 . The Company also owns other mineral properties. The weighted average life for these probable owned mineral reserves is 42 years as of December 31, 2015 based upon current annual capacities. Buildings and structures are depreciated on a straight line basis over lives generally ranging from 10 to 30 years. Portable buildings generally have shorter lives than permanent structures. Leasehold and building improvements typically have shorter estimated lives of 5 to 20 years or lower based on the life of the lease to which the improvement relates. The Company’s other fixed assets are amortized on a straight-line basis over their respective lives. The following table summarizes the estimated useful lives of the Company’s different classes of property, plant and equipment: Years Land improvements 10 to 25 Buildings and structures 10 to 30 Leasehold and building improvements 5 to 40 Machinery and equipment – vehicles 3 to 10 Machinery and equipment – other mining and production 3 to 50 Office furniture and equipment 3 to 10 Mineral interests 20 to 99 The Company has capitalized computer software costs of $28.0 million and $16.9 million as of December 31, 2015 and 2014 , respectively, recorded in property, plant and equipment. The capitalized costs are being amortized over 5 years. The Company recorded $2.2 million , $1.6 million and $1.3 million of amortization expense for 2015 , 2014 and 2013 , respectively. The Company recognizes and measures obligations related to the retirement of tangible long-lived assets in accordance with applicable U.S. GAAP. Asset retirement obligations are not material to the Company’s financial position, results of operations or cash flows. The Company reviews its long-lived assets and the related mineral reserves for impairment whenever events or changes in circumstances indicate the carrying amounts of such assets may not be recoverable. If an indication of a potential impairment exists, recoverability of the respective assets is determined by comparing the forecasted undiscounted net cash flows of the operation to which the assets relate, to the carrying amount, including associated intangible assets, of such operation. If the operation is determined to be unable to recover the carrying amount of its assets, then intangible assets are written down first, followed by the other long-lived assets of the operation, to fair value. Fair value is determined based on discounted cash flows or appraised values, depending upon the nature of the assets.
Goodwill and Intangible Assets	Goodwill and Intangible Assets: The Company amortizes its intangible assets deemed to have finite lives on a straight-line basis over their estimated useful lives which, for Compass Minerals, range from 5 to 50 years. The Company reviews goodwill and other indefinite-lived intangible assets annually for impairment. In addition, goodwill and other intangible assets are reviewed when an event or change in circumstances indicates the carrying amounts of such assets may not be recoverable. During the fourth quarter of 2015, the Company voluntarily changed the date of its annual goodwill and indefinite-lived intangible assets impairment testing from December 1, to the first day of the fourth quarter, October 1. This voluntary change is preferable under the circumstances as it provides the Company with additional time to complete its annual goodwill and indefinite-lived intangible asset impairment testing in advance of its year-end reporting and results in better alignment with the Company’s strategic forecasting and budgeting process. The voluntary change in accounting principle related to the annual testing date will not delay, accelerate or avoid an impairment charge. This change is not applied retrospectively as it is impracticable to do so because retrospective application would require application of significant estimates and assumptions with the use of hindsight. Accordingly, the change will be applied prospectively.
Investments	Investment Our investment in a Brazilian manufacturer and distributor of specialty plant nutrients (see Note 3) is accounted for using the equity method, as our ownership interest is 50% or less and allows us to exercise significant influence over the operating and financial policies of the investee. In accordance with the equity method, our original investment was recorded at cost (including certain capitalized transaction costs) and will be adjusted by our share of the investee’s undistributed earnings and losses.
Other Noncurrent Assets	Other Noncurrent Assets: Other noncurrent assets include deferred financing costs of $8.5 million as of December 31, 2015 and 2014 with accumulated amortization of $3.9 million and $2.7 million as of December 31, 2015 and 2014 , respectively. In connection with the debt refinancing in June 2014, the Company incurred approximately $8.1 million of costs, including $4.1 million of fees that were capitalized as deferred financing costs related to the $250.0 million senior notes (" 4.875% Senior Notes") and $4.0 million in call premiums. The $4.0 million paid for call premiums along with the write-off of $1.4 million of the Company’s unamortized deferred financing costs and approximately $1.5 million of original issue discount, each related to the $100.0 million senior notes (" 8% Senior Notes"), were recorded in other expense in the consolidated statements of operations for 2014 . In December 2013, the Company amended and extended to August 2017 (previously October 2015) its existing revolving credit facility. In connection with this transaction, the Company paid and capitalized approximately $0.6 million of deferred financing costs. Deferred financing costs are being amortized to interest expense over the terms of the debt to which the costs relate. Certain inventories of spare parts and related inventory, net of reserve, of approximately $11.0 million and $13.7 million at December 31, 2015 and 2014 , respectively, which will be utilized with respect to long-lived assets, have been classified in the consolidated balance sheets as other noncurrent assets. The Company sponsors a non-qualified defined contribution plan for certain of its executive officers and key employees as described in Note 9. As of December 31, 2015 and 2014 , investments in marketable securities representing amounts deferred by employees, Company contributions and unrealized gains or losses totaling $1.6 million and $1.9 million , respectively, were included in other noncurrent assets in the consolidated balance sheets. The marketable securities are classified as trading securities and accordingly, gains and losses are recorded as a component of other (income) expense, net in the consolidated statements of operations.
Income Taxes	Income Taxes: The Company accounts for income taxes using the liability method in accordance with the provisions of U.S. GAAP. Under the liability method, deferred taxes are determined based on the differences between the financial statement and the tax basis of assets and liabilities using enacted tax rates in effect in the years in which the differences are expected to reverse. The Company’s foreign subsidiaries file separate company returns in their respective jurisdictions. The Company recognizes potential liabilities in accordance with applicable U.S. GAAP for anticipated tax issues in the U.S. and other tax jurisdictions based on its estimate of whether, and the extent to which, additional taxes will be due. If payment of these amounts ultimately proves to be unnecessary, the reversal of the liabilities would result in tax benefits being recognized in the period when the Company determines the liabilities are no longer necessary. If the Company’s estimate of tax liabilities proves to be less than the ultimate assessment, a further charge to expense would result. Any penalties and interest that are accrued on the Company’s uncertain tax positions are included as a component of income tax expense. In evaluating the Company’s ability to realize deferred tax assets, the Company considers the sources and timing of taxable income, including the reversal of existing temporary differences, the ability to carryback tax attributes to prior periods, qualifying tax-planning strategies, and estimates of future taxable income exclusive of reversing temporary differences. In determining future taxable income, the Company’s assumptions include the amount of pre-tax operating income according to different state, federal and international taxing jurisdictions, the origination of future temporary differences, and the implementation of feasible and prudent tax-planning strategies. If the Company determines that a portion of its deferred tax assets will not be realized, a valuation allowance is recorded in the period that such determination is made. In the future, if the Company determines, based on the existence of sufficient evidence, that more or less of the deferred tax assets are more likely than not to be realized, an adjustment to the valuation allowance will be made in the period such a determination is made.
Environmental Costs	Environmental Costs: Environmental costs, other than those of a capital nature, are accrued at the time the exposure becomes known and costs can be reasonably estimated. Costs are accrued based upon management’s estimates of all direct costs. The Company’s environmental accrual was $1.4 million and $1.5 million at December 31, 2015 and 2014 , respectively.
Equity Compensation Plans	Equity Compensation Plans: The Company has equity compensation plans under the oversight of the board of directors of Compass Minerals, whereby stock options, restricted stock units, deferred stock units and performance stock units are granted to employees or directors of the Company.
Earnings per Share	Earnings per Share: The Company’s participating securities are accounted for in accordance with guidance related to the computation of earnings per share under the two-class method. The two-class method requires allocating the Company’s net earnings to both common shares and participating securities based upon their rights to receive dividends. Basic earnings per share is computed by dividing net earnings available to common shareholders by the weighted-average number of outstanding common shares during the period. Diluted earnings per share reflects the potential dilution that could occur under the more dilutive of either the treasury stock method or the two-class method for calculating the weighted-average number of outstanding common shares. The treasury stock method is calculated assuming unrecognized compensation expense, income tax benefits and proceeds from the potential exercise of employee stock options are used to repurchase common stock.
Derivatives	Derivatives: The Company is exposed to the impact of fluctuations in the purchase price of natural gas consumed in operations. The Company hedges portions of its risk of changes in natural gas prices through the use of derivative agreements. The Company accounts for derivative financial instruments in accordance with applicable U.S. GAAP, which requires companies to record derivative financial instruments as assets or liabilities measured at fair value. Accounting for the changes in the fair value of a derivative depends on its designation and effectiveness. Derivatives qualify for treatment as hedges when there is a high correlation between the change in fair value of the derivative instrument and the related change in value of the underlying hedged item. For qualifying hedges, the effective portion of the change in fair value is recognized through earnings when the underlying transaction being hedged affects earnings, allowing a derivative’s gains and losses to offset related results from the hedged item in the statements of operations. For derivative instruments that are not accounted for as hedges, or for the ineffective portions of qualifying hedges, the change in fair value is recorded through earnings in the period of change. The Company formally documents, designates, and assesses the effectiveness of transactions that receive hedge accounting treatment initially and on an ongoing basis. The Company does not engage in trading activities with its financial instruments.
Concentration of Credit Risk	Concentration of Credit Risk: The Company sells its salt and magnesium chloride products to various governmental agencies, manufacturers, distributors and retailers primarily in the Midwestern U.S., and throughout Canada and the U.K. The Company’s plant nutrition products are sold across North America and internationally.
Recent Accounting Pronouncements	Recent Accounting Pronouncements: In November 2015, the Financial Accounting Standards Board ("FASB") issued guidance which simplifies the presentation of deferred income taxes by eliminating the requirement that an entity separate deferred income tax assets and liabilities into current and noncurrent in a classified statement of financial position. Under this guidance, deferred tax assets and liabilities are required to be classified as noncurrent. The amendments are effective for financial statements issued for annual periods beginning after December 15, 2016, and interim periods within those annual periods. Early adoption is permitted for all entities as of the beginning of an interim or annual reporting period. The Company has elected to prospectively adopt the accounting standard as of the beginning of the Company's fourth quarter of 2015. Prior periods in our Consolidated Financial Statements were not retrospectively adjusted. In July 2015, the FASB issued guidance that requires entities to measure inventory within the scope of the standard at the lower of cost or net realizable value. "Net realizable value" is defined as the estimated selling prices in the ordinary course of business, less reasonably predictable costs of completion, disposal and transportation. The guidance is effective for fiscal years, and interim periods within those years, beginning after December 15, 2016. Early adoption is permitted. The Company does not expect that this guidance will have a material impact on its consolidated financial statements. In April 2015, the FASB issued guidance about whether fees paid by customers in cloud computing arrangements include a software license. If a cloud computing arrangement includes a software license, a customer should account for the software license element in a manner consistent with previously issued guidance for software licenses. If the arrangement does not include a software license, a customer should account for the arrangement as a service contract. The guidance is effective for fiscal years, and interim periods within those years, beginning after December 15, 2015. An entity can adopt the guidance prospectively or retrospectively and early adoption is permitted. The Company does not expect that this guidance will have a material impact on its consolidated financial statements. In April 2015, the FASB issued guidance which requires debt issuance costs to be presented in the balance sheet as a direct deduction from the related debt liability rather than an asset. The recognition and measurement guidance for debt issuance costs are not affected by this guidance. This new guidance is effective retrospectively for fiscal years, and interim periods within those years, beginning after December 15, 2015. Early adoption is permitted. The Company will adopt this guidance in the first quarter of 2016. The Company does not expect that this guidance will have a material impact on its consolidated financial statements. In August 2014, the FASB issued guidance which requires management to evaluate whether there is substantial doubt about an entity’s ability to continue as a going concern and to provide disclosure in the footnotes under certain circumstances. This guidance is effective for fiscal years ending after December 15, 2016 with early adoption permitted. The Company does not expect that this guidance will have a material impact on its consolidated financial statements. In May 2014, the FASB issued guidance to provide a single, comprehensive revenue recognition model for all contracts with customers. The new revenue recognition model supersedes existing revenue recognition guidance and requires revenue recognition to depict the transfer of promised goods or services to customers in an amount that reflects the consideration an entity expects to receive in exchange for those goods or services. This guidance is effective for fiscal years and interim periods with those years beginning after December 15, 2017 and early adoption is not permitted. The guidance permits the use of either a full or modified retrospective or cumulative effect transition method. The Company is currently evaluating the impact that the implementation of this standard will have on its consolidated financial statements.

SUMMARY OF SIGNIFICANT ACCOUN29

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)	12 Months Ended
	Dec. 31, 2015
Accounting Policies [Abstract]
Estimated useful lives of property, plant and equipment	The following table summarizes the estimated useful lives of the Company’s different classes of property, plant and equipment: Years Land improvements 10 to 25 Buildings and structures 10 to 30 Leasehold and building improvements 5 to 40 Machinery and equipment – vehicles 3 to 10 Machinery and equipment – other mining and production 3 to 50 Office furniture and equipment 3 to 10 Mineral interests 20 to 99

INVENTORIES (Tables)

INVENTORIES (Tables)	12 Months Ended
	Dec. 31, 2015
Inventory Disclosure [Abstract]
Inventories	Inventories consist of the following at December 31 (in millions): 2015 2014 Finished goods $ 223.1 $ 148.5 Raw materials and supplies 52.2 50.5 Total inventories $ 275.3 $ 199.0

PROPERTY PLANT AND EQUIPMENT (T

PROPERTY PLANT AND EQUIPMENT (Tables)	12 Months Ended
	Dec. 31, 2015
Property, Plant and Equipment [Abstract]
Property, plant and equipment	Property, plant and equipment consists of the following at December 31 (in millions): 2015 2014 Land, buildings and structures and leasehold improvements $ 347.3 $ 352.2 Machinery and equipment 701.5 669.1 Office furniture and equipment 25.4 17.5 Mineral interests 169.6 179.6 Construction in progress 191.5 108.9 1,435.3 1,327.3 Less accumulated depreciation and depletion (634.6 ) (626.4 ) Property, plant and equipment, net $ 800.7 $ 700.9

GOODWILL AND OTHER INTANGIBLE32

GOODWILL AND OTHER INTANGIBLE ASSETS (Tables)	12 Months Ended
	Dec. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of finite-lived intangible assets	The asset value and accumulated amortization as of December 31, 2015 and December 31, 2014 for the finite-lived intangibles assets are as follows (in millions): Supply Agreement SOP Production Rights Customer/ Distributor Relationships Lease Rights Patents Other Total December 31, 2015 Gross intangible asset $ 26.1 $ 24.3 $ 7.0 $ 1.6 $ 14.9 $ 3.9 $ 77.8 Accumulated amortization (2.6 ) (11.7 ) (2.5 ) (0.2 ) (2.3 ) (1.2 ) (20.5 ) Net intangible assets $ 23.5 $ 12.6 $ 4.5 $ 1.4 $ 12.6 $ 2.7 $ 57.3 Supply Agreement SOP Production Rights Customer Relationships Lease Rights Patents Other Total December 31, 2014 Gross intangible asset $ 31.3 $ 24.3 $ 8.1 $ 1.9 $ 17.9 $ 4.6 $ 88.1 Accumulated amortization (2.5 ) (10.8 ) (2.0 ) (0.2 ) (1.2 ) (0.6 ) (17.3 ) Net intangible assets $ 28.8 $ 13.5 $ 6.1 $ 1.7 $ 16.7 $ 4.0 $ 70.8
Estimated lives of intangible assets	The estimated lives of the Company’s intangible assets are as follows: Intangible asset Estimated Lives Supply agreement 50 years SOP production rights 25 years Patents 10-20 years Developed technology 5 years Lease rights 25 years Customer and distributor relationships 10 years Trademarks 10 years Noncompete agreements 5 years Trade names Indefinite Water rights Indefinite

INCOME TAXES (Tables)

INCOME TAXES (Tables)	12 Months Ended
	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Income tax provision (benefit) related to earnings	The following table summarizes the Company’s income tax provision (benefit) related to earnings for the years ended December 31 (in millions): 2015 2014 2013 Current: Federal $ 31.7 $ 37.4 $ 23.2 State 7.3 9.5 5.7 Foreign 16.4 23.4 14.6 Total current 55.4 70.3 43.5 Deferred: Federal (0.2 ) (3.6 ) (2.5 ) State — (0.9 ) (0.6 ) Foreign 0.1 8.1 2.9 Total deferred (0.1 ) 3.6 (0.2 ) Total provision for income taxes $ 55.3 $ 73.9 $ 43.3
Income tax expense reconciliation	The following table summarizes components of earnings before taxes and shows the tax effects of significant adjustments from the expected tax expense computed at the federal statutory rate for the years ended December 31 (in millions): 2015 2014 2013 Domestic income $ 170.6 $ 184.3 $ 112.3 Foreign income 43.9 107.5 61.8 Earnings before income taxes 214.5 291.8 174.1 Computed tax at the U.S. federal statutory rate of 35% 75.1 102.1 60.9 Foreign income rate differential, mining, and withholding taxes, net of U.S. federal deduction (1.2 ) (9.3 ) (2.6 ) Percentage depletion in excess of basis (11.2 ) (11.8 ) (9.0 ) Other domestic tax reserves, net of reversals (4.5 ) (3.9 ) (0.9 ) Domestic manufacturers deduction (2.4 ) (2.5 ) (1.3 ) State income taxes, net of federal income tax benefit 5.1 5.5 3.4 Interest expense recognition differences (6.1 ) (7.1 ) (7.0 ) Other, net 0.5 0.9 (0.2 ) Provision for income taxes $ 55.3 $ 73.9 $ 43.3 Effective tax rate 26 % 25 % 25 %
Significant components of deferred tax assets and liabilities	The significant components of the Company’s deferred tax assets and liabilities were as follows at December 31 (in millions): 2015 2014 Current deferred tax assets (a) : Accrued expenses $ — $ 3.5 Other, net — 6.2 Current deferred tax assets — 9.7 Current deferred tax liabilities (a) : Other, net — 0.4 Current deferred tax liabilities — 0.4 Noncurrent deferred taxes: Property, plant and equipment 73.0 77.6 Intangible asset 13.9 17.7 Other, net 3.3 2.7 Total noncurrent deferred tax liabilities 90.2 98.0 Deferred tax assets: Net operating loss carryforwards 2.6 0.8 Stock-based compensation 4.7 3.7 Other, net 12.5 5.6 Subtotal 19.8 10.1 Valuation allowance (0.9 ) (1.0 ) Total noncurrent deferred tax assets 18.9 9.1 Net noncurrent deferred tax liabilities $ 71.3 $ 88.9 (a) The Company elected to prospectively adopt guidance from the FASB which requires deferred tax assets and liabilities to be presented as noncurrent in its consolidated balance sheets. This guidance was elected prospectively and the prior period was not retrospectively adjusted (see Recent Accounting Pronouncements in Note 2).
Reconciliation of unrecognized tax benefits	The following table shows a reconciliation of the beginning and ending amount of unrecognized tax benefits (in millions): 2015 2014 2013 Unrecognized tax benefits: Balance at January 1 $ 21.8 $ 24.6 $ 25.3 Additions resulting from current year tax positions 1.6 1.0 1.0 Additions relating to tax positions taken in prior years 0.8 1.1 — Reductions due to cash payments (0.8 ) (0.3 ) (0.8 ) Reductions relating to tax positions taken in prior years (2.4 ) (1.2 ) (0.9 ) Reductions due to expiration of tax years (2.7 ) (3.4 ) — Balance at December 31 $ 18.3 $ 21.8 $ 24.6

PENSION PLANS AND OTHER BENEF34

PENSION PLANS AND OTHER BENEFITS (Tables)	12 Months Ended
	Dec. 31, 2015
Compensation and Retirement Disclosure [Abstract]
Weighted-average asset allocations	The weighted-average asset allocations by asset category are as follows: Plan Assets at December 31, Asset Category 2015 2014 Cash and cash equivalents 1 % 1 % Equity funds — % 53 % Blended funds 32 % — % Bond funds 45 % 46 % Insurance policy 22 % — % Total 100 % 100 %
Fair value of pension plan assets	The fair value of the Company’s pension plan assets at December 31, 2015 , and 2014 by asset category (see Note 14 for a discussion regarding fair value measurements) are as follows (in millions): Market Value at December 31, 2015 Level One Level Two Level Three Asset category: Cash and cash equivalents (a) $ 0.9 $ 0.9 $ — $ — Equity funds — — — — Blended funds (b) 21.1 — 21.1 — Bond funds (c) : Treasuries 30.3 — 30.3 — Insurance policy (d) 14.6 — — 14.6 Total Pension Assets $ 66.9 $ 0.9 $ 51.4 $ 14.6 (a) The fair value of cash and cash equivalents is its carrying value. (b) The Company is invested in a diversified growth fund. The diversified growth fund is valued at the last traded or official close for the underlying equities and bid or mid for the underlying fixed income securities depending on the portfolio benchmark. Where representative prices are unavailable, underlying fixed income investments are valued based on other observable market-based inputs. (c) This category includes investments in investment-grade fixed-income instruments and funds linked to U.K. treasury notes. The funds are valued using the bid amounts for each fund. All of the Company’s bond fund pension assets are invested in U.K.-linked treasuries as of December 31, 2015 . (d) The insurance policy has been written by an insurance company with an A+ rating from Standard and Poors. The policy derives its value primarily from its underlying investments which consists of separate funds also managed by the underwriter. The policy’s holdings consist primarily of a unit trust fund, which is valued based on its underlying holdings of equities, fixed income securities, cash, and derivative instruments. Those underlying investments are valued at bid price on the last business day of the period when available. Other investments use the last available authorized price of the last business day of the period. Unquoted investments are valued based upon the fund manager’s opinion of fair value based primarily on other observable market-based inputs. Open positions in derivative contracts or foreign currency transactions are included at their mark to market value. Money market instruments are valued based upon amortized cost. Term deposits are valued at their nominal value. Market Value at December 31, 2014 Level One Level Two Level Three Asset category: Cash and cash equivalents (a) $ 1.0 $ 1.0 $ — $ — Equity funds 37.0 — 37.0 — Bond funds (b) : Treasuries 32.3 — 32.3 — Total Pension Assets $ 70.3 $ 1.0 $ 69.3 $ — (a) The fair value of cash and cash equivalents is its carrying value. (b) This category includes investments in investment-grade fixed-income instruments and funds linked to U.K. treasury notes. The funds are valued using the bid amounts for each fund. All of the Company’s bond fund pension assets are invested in U.K.-linked treasuries as of December 31, 2014 .
Changes in level 3 pension plan assets	The changes in Level 3 pension plan assets for the year ended December 31, 2015 were as follows (in millions): Year Ended December 31, 2015 Value of Insurance Policy Beginning balance as of January 1, 2015 $ — Purchase 15.4 Unrealized loss (0.1 ) Currency fluctuation adjustment (0.7 ) Ending balance as of December 31, 2015 $ 14.6
Assumptions used in determining pension information	The assumptions used in determining pension information for the plans for the years ended December 31 were as follows: 2015 2014 2013 Discount rate 3.40 % 4.40 % 4.40 % Expected return on plan assets 4.30 % 5.30 % 4.60 %
Future expected benefit payments	The Company expects to pay the following benefit payments (in millions): Calendar Year Future Expected Benefit Payments 2016 $ 2.8 2017 2.9 2018 3.0 2019 3.1 2020 3.2 2021 – 2025 17.4
Pension obligations, plan assets and net funded status	The following table sets forth pension obligations and plan assets for the Company’s defined benefit plan, as of December 31 (in millions): 2015 2014 Change in benefit obligation: Benefit obligation as of January 1 $ 76.8 $ 73.6 Interest cost 2.5 3.2 Actuarial (gain) loss (5.5 ) 7.6 Benefits paid (2.9 ) (2.9 ) Currency fluctuation adjustment (4.0 ) (4.7 ) Benefit obligation as of December 31 66.9 76.8 Change in plan assets: Fair value as of January 1 70.3 66.7 Actual return 1.9 9.2 Company contributions 1.5 1.6 Currency fluctuation adjustment (3.9 ) (4.3 ) Benefits paid (2.9 ) (2.9 ) Fair value of plan assets as of December 31 66.9 70.3 Underfunded status of the plan $ — $ (6.5 )
Components of net pension expense	The components of net pension expense were as follows for the years ended December 31 (in millions): 2015 2014 2013 Interest cost on projected benefit obligation $ 2.5 $ 3.2 $ 3.0 Prior service cost (0.1 ) (0.1 ) (0.1 ) Expected return on plan assets (2.9 ) (3.5 ) (2.8 ) Net amortization 1.5 1.7 1.8 Net pension expense $ 1.0 $ 1.3 $ 1.9

LONG TERM DEBT (Tables)

LONG TERM DEBT (Tables)	12 Months Ended
	Dec. 31, 2015
Debt Disclosure [Abstract]
Long-term debt	Third-party long-term debt consists of the following at December 31 (in millions): 2015 2014 Term Loan due May 2017 $ 472.5 $ 376.4 Revolving Credit Facility due August 2017 4.5 — 4.875% Senior Notes due July 2024 250.0 250.0 727.0 626.4 Less current portion (4.9 ) (3.9 ) Long-term debt $ 722.1 $ 622.5
Future maturities of long-term debt	Future maturities of long-term debt for the years ending December 31, are as follows (in millions): Debt Maturity 2016 $ 4.9 2017 472.1 2018 — 2019 — 2020 — Thereafter 250.0 Total $ 727.0

DERIVATIVES AND FAIR VALUES O36

DERIVATIVES AND FAIR VALUES OF FINANCIAL INSTRUMENTS (Tables)	12 Months Ended
	Dec. 31, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Fair value of hedged items	The following tables present the fair value of the Company’s hedged items as of December 31, 2015 , and December 31, 2014 (in millions): Asset Derivatives Liability Derivatives Derivatives designated as hedging instruments (a) : Balance Sheet Location December 31, 2015 Balance Sheet Location December 31, 2015 Commodity contracts (b) Other current assets $ 0.1 Accrued expenses $ 2.6 Commodity contracts Other assets — Other noncurrent liabilities 0.1 Total derivatives designated as hedging instruments $ 0.1 $ 2.7 (a) The Company has commodity hedge agreements with two counterparties. Amounts recorded as liabilities for the Company’s commodity contracts are payable to both counterparties. (b) The Company has master netting agreements with its counterparties and accordingly has netted in its consolidated balance sheets approximately $0.1 million of its commodity contracts that are in a receivable position against its contracts in payable positions. Asset Derivatives Liability Derivatives Derivatives designated as hedging instruments (a) : Balance Sheet Location December 31, 2014 Balance Sheet Location December 31, 2014 Commodity contracts (b) Other current assets $ 0.1 Accrued expenses $ 2.5 Commodity contracts Other assets — Other noncurrent liabilities 1.0 Total derivatives designated as hedging instruments $ 0.1 $ 3.5 (a) The Company has commodity hedge agreements with four counterparties. Amounts recorded as liabilities for the Company’s commodity contracts are payable to all counterparties. The amount recorded as an asset is due from two counterparties. (b) The Company has master netting agreements with its counterparties and accordingly has netted in its consolidated balance sheets approximately $0.1 million of its commodity contracts that are in a receivable position against its contracts in payable positions.
Other comprehensive income attributable to derivatives	The following tables present activity related to the Company’s other comprehensive income for the twelve months ended December 31, 2015 and December 31, 2014 (in millions): Twelve Months Ended December 31, 2015 Derivatives in Cash Flow Hedging Relationships Location of Gain (Loss) Reclassified from Accumulated OCI Into Income (Effective Portion) Amount of (Gain) Loss Recognized in OCI on Derivative (Effective Portion) Amount of Gain (Loss) Reclassified from Accumulated OCI Into Income (Effective Portion) Commodity contracts Product cost $ 2.4 $ (3.1 ) Total $ 2.4 $ (3.1 ) Twelve Months Ended December 31, 2014 Derivatives in Cash Flow Hedging Relationships Location of Gain (Loss) Reclassified from Accumulated OCI Into Income (Effective Portion) Amount of (Gain) Loss Recognized in OCI on Derivative (Effective Portion) Amount of Gain (Loss) Reclassified from Accumulated OCI Into Income (Effective Portion) Commodity contracts Product cost $ 2.8 $ 1.0 Total $ 2.8 $ 1.0

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Tables)	12 Months Ended
	Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Aggregate future minimum annual rentals under lease arrangements	The aggregate future minimum annual rentals under lease arrangements as of December 31, 2015 , are as follows (in millions): Operating Leases 2016 $ 15.7 2017 9.7 2018 4.1 2019 3.6 2020 1.9 Thereafter 5.0 Total $ 40.0

STOCKHOLDERS' EQUITY AND EQUI38

STOCKHOLDERS' EQUITY AND EQUITY INSTRUMENTS (Tables)	12 Months Ended
	Dec. 31, 2015
Stockholders' Equity and Equity Instruments [Abstract]
Stock-based compensation activity	The following is a summary of CMP’s stock option, RSU and PSU activity and related information for the following periods: Stock Options RSUs PSUs Number Weighted-average exercise price Number Weighted-average fair value Number Weighted-average fair value Outstanding at December 31, 2012 435,721 $ 67.46 77,749 $ 78.46 49,932 $ 83.58 Granted 124,370 76.84 65,521 74.99 29,134 78.01 Exercised (a) (174,149 ) 60.71 — — — — Released from restriction (a) — — (22,658 ) 78.46 (6,341 ) 86.51 Cancelled/Expired (57,578 ) 77.19 (24,894 ) 78.42 (17,576 ) 81.72 Outstanding at December 31, 2013 328,364 $ 72.88 95,718 $ 76.09 55,149 $ 80.89 Granted 95,610 87.18 20,268 86.74 27,574 105.77 Exercised (a) (112,005 ) 67.35 — — — — Released from restriction (a) — — (15,636 ) 86.48 (3,998 ) 93.82 Cancelled/Expired (33,540 ) 79.81 (11,818 ) 76.95 (19,098 ) 89.77 Outstanding at December 31, 2014 278,429 $ 79.23 88,532 $ 76.58 59,627 $ 88.69 Granted 120,956 91.76 21,317 90.94 35,584 100.49 Exercised (a) (33,906 ) 72.53 — — — — Released from restriction (a) — — (15,952 ) 71.69 (10,454 ) 74.49 Cancelled/Expired (b) (12,392 ) 84.71 (2,889 ) 81.43 (7,392 ) 82.46 Outstanding at December 31, 2015 353,087 $ 83.94 91,008 $ 80.65 77,365 $ 96.63 (a) Common stock issued for exercised options and RSUs and PSUs released from restriction were issued from treasury shares. (b) The performance period for the 2013 PSU grant was completed in 2015 . The Company expects to issue 9,914 shares in March 2016 when the 2013 PSU grant vests.
Weighted average assumptions and fair value for options granted	The weighted average assumptions and fair values for options granted for each of the years ended December 31 is included in the following table. 2015 2014 2013 Fair value of options granted $ 14.78 $ 15.25 $ 19.06 Expected term (years) 4.8 4.8 4.7 Expected volatility 24.9 % 27.8 % 38.0 % Dividend yield 3.1 % 3.4 % 3.0 % Risk-free interest rates 1.6 % 1.5 % 0.9 %
Summary of information about options outstanding and exercisable	The following table summarizes information about options outstanding and exercisable at December 31, 2015 . Options Outstanding Options Exercisable Range of exercise prices Options outstanding Weighted-average remaining contractual life (years) Weighted-average exercise price of options outstanding Options exercisable Weighted-average remaining contractual life (years) Weighted-average exercise price of exercisable options $58.99 - $77.75 114,116 3.7 $ 74.16 63,633 3.3 $ 72.74 $77.76 - $86.99 42,130 1.7 82.51 42,130 1.7 82.51 $87.00 - $89.47 79,717 5.2 87.18 18,445 5.2 87.18 $89.48 - $93.26 117,124 6.2 91.77 74 6.2 91.75 Totals 353,087 4.6 $ 83.94 124,282 3.1 $ 78.21
Components of and changes in accumulated other comprehensive income (loss)	The components of and changes in accumulated other comprehensive income (loss) ("AOCI") for the twelve months ended December 31, 2015 and 2014 are as follows (in millions): Twelve Months Ended December 31, 2015 (a) Gains and (Losses) on Cash Flow Hedges Defined Benefit Pension Foreign Currency Total Beginning balance $ (2.0 ) $ (9.0 ) $ (4.5 ) $ (15.5 ) Other comprehensive income (loss) before reclassifications (1.5 ) 4.1 (98.4 ) (95.8 ) Amounts reclassified from accumulated other comprehensive loss 1.9 1.1 — 3.0 Net current period other comprehensive income (loss) 0.4 5.2 (98.4 ) (92.8 ) Ending balance $ (1.6 ) $ (3.8 ) $ (102.9 ) $ (108.3 ) (a) With the exception of the cumulative foreign currency translation adjustment, for which no tax effect is recorded, the changes in the components of accumulated other comprehensive gain (loss) presented in the table are reflected net of applicable income taxes. Twelve Months Ended December 31, 2014 (a) Gains and (Losses) on Cash Flow Hedges Defined Benefit Pension Foreign Currency Total Beginning balance $ 0.3 $ (9.3 ) $ 43.5 $ 34.5 Other comprehensive income (loss) before reclassifications (1.7 ) (1.0 ) (48.0 ) (50.7 ) Amounts reclassified from accumulated other comprehensive loss (0.6 ) 1.3 — 0.7 Net current period other comprehensive income (loss) (2.3 ) 0.3 (48.0 ) (50.0 ) Ending balance $ (2.0 ) $ (9.0 ) $ (4.5 ) $ (15.5 ) (a) With the exception of the cumulative foreign currency translation adjustment, for which no tax effect is recorded, the changes in the components of accumulated other comprehensive gain (loss) presented in the table are reflected net of applicable income taxes.
Changes in the components of accumulated other comprehensive gain (loss)	Amount Reclassified from AOCI Twelve Months Ended December 31, 2015 Line Item Impacted in the Consolidated Statement of Operations Gains and (losses) on cash flow hedges: Natural gas instruments $ 3.1 Product cost (1.2 ) Income tax expense (benefit) 1.9 Amortization of defined benefit pension: Amortization of loss $ 1.4 Product cost (0.3 ) Income tax expense (benefit) 1.1 Total reclassifications, net of income taxes $ 3.0 Amount Reclassified from AOCI Twelve Months Ended December 31, 2014 Line Item Impacted in the Consolidated Statement of Operations Gains and (losses) on cash flow hedges: Natural gas instruments $ (1.0 ) Product cost 0.4 Income tax expense (benefit) (0.6 ) Amortization of defined benefit pension: Amortization of loss $ 1.6 Product cost (0.3 ) Income tax expense (benefit) 1.3 Total reclassifications, net of income taxes $ 0.7

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	12 Months Ended
	Dec. 31, 2015
Fair Value Disclosures [Abstract]
Estimated fair values for each type of instrument	The estimated fair values for each type of instrument are presented below (in millions). December 31, 2015 Level One Level Two Level Three Asset Class: Mutual fund investments in a non-qualified savings plan (a) $ 1.6 $ 1.6 $ — $ — Total Assets $ 1.6 $ 1.6 $ — $ — Liability Class: Liabilities related to non-qualified savings plan $ (1.6 ) $ (1.6 ) $ — $ — Derivatives – natural gas instruments (2.6 ) — (2.6 ) — Total Liabilities $ (4.2 ) $ (1.6 ) $ (2.6 ) $ — (a) Includes mutual fund investments of approximately 20% in the common stock of large-cap U.S. companies, approximately 5% in the common stock of small to mid-cap U.S. companies, approximately 5% in the common stock of international companies, approximately 5% in bond funds, approximately 35% in short-term investments and approximately 30% in blended funds. December 31, 2014 Level One Level Two Level Three Asset Class: Mutual fund investments in a non-qualified savings plan (a) $ 1.9 $ 1.9 $ — $ — Total Assets $ 1.9 $ 1.9 $ — $ — Liability Class: Liabilities related to non-qualified savings plan $ (1.9 ) $ (1.9 ) $ — $ — Derivatives – natural gas instruments (3.4 ) — (3.4 ) — Total Liabilities $ (5.3 ) $ (1.9 ) $ (3.4 ) $ — (a) Includes mutual fund investments of approximately 15% in the common stock of large-cap U.S. companies, approximately 5% in the common stock of international companies, approximately 5% in bond funds, approximately 35% in short-term investments and approximately 40% in blended funds.

OPERATING SEGMENTS (Tables)

OPERATING SEGMENTS (Tables)	12 Months Ended
	Dec. 31, 2015
Segment Reporting [Abstract]
Segment information	Segment information as of and for the years ended December 31, is as follows (in millions): 2015 Salt Plant Nutrition Corporate & Other (a) Total Sales to external customers $ 849.0 $ 238.4 $ 11.3 $ 1,098.7 Intersegment sales 0.1 7.7 (7.8 ) — Shipping and handling cost 239.1 22.4 — 261.5 Operating earnings (loss) 215.2 57.9 (51.7 ) 221.4 Depreciation, depletion and amortization 43.9 29.8 4.6 78.3 Total assets (b) 896.5 679.7 52.7 1,628.9 Capital expenditures 106.5 92.8 18.3 217.6 2014 Salt Plant Nutrition Corporate & Other (a) Total Sales to external customers $ 1,002.6 $ 270.2 $ 9.7 $ 1,282.5 Intersegment sales 0.9 7.1 (8.0 ) — Shipping and handling cost 309.3 28.4 — 337.7 Operating earnings (loss) (c) 291.4 74.8 (55.2 ) 311.0 Depreciation, depletion and amortization 44.8 27.3 5.9 78.0 Total assets 1,045.2 536.2 55.8 1,637.2 Capital expenditures 67.9 42.1 15.2 125.2 2013 Salt Plant Nutrition Corporate & Other (a) Total Sales to external customers $ 920.5 $ 198.6 $ 10.5 $ 1,129.6 Intersegment sales 0.9 7.2 (8.1 ) — Shipping and handling cost 280.7 21.0 — 301.7 Operating earnings (loss) (b) 181.3 58.7 (54.4 ) 185.6 Depreciation, depletion and amortization 45.1 23.8 4.1 73.0 Total assets 942.2 386.8 75.8 1,404.8 Capital expenditures (d) 79.8 38.8 4.1 122.7 (a) Corporate and Other includes corporate entities, records management operations and other incidental operations and eliminations. Operating earnings (loss) for corporate and other includes indirect corporate overhead including costs for general corporate governance and oversight, as well as costs for the human resources, information technology and finance functions. In 2014 , the operating earnings loss includes costs of approximately $4.2 million to consolidate its records management locations by closing one location in London, England. (b) In 2015, the Company's equity investment in Produquímica is included in total assets for its plant nutrition segment. In addition, the Company's assets held for sale have been presented in corporate and other. Total assets in 2015 for both operating segments were negatively impacted by the impact of translating our foreign-denominated assets into U.S. dollars. (c) In 2014 , the Company recorded a gain of $82.3 million in the salt segment and $1.0 million in corporate and other resulting from an insurance settlement related to a tornado at its salt facilities in Goderich, Ontario in August 2011. In the fourth quarter of 2013 , the Company recognized a gain of $9 million in its plant nutrition segment from the settlement of an insurance claim resulting from a loss of mineral-concentrated brine due to an asset failure at its solar evaporation ponds in 2010 and a charge of $4.7 million in its salt segment from a ruling against the Company related to a labor matter. (d) The salt segment includes approximately $15 million of capital expenditures during 2013 to replace and, in some instances, improve property, plant and equipment damaged or destroyed by the tornado at the Company’s Goderich, Ontario facilities in 2011.
Schedule of revenue from external customers and long-lived assets	Financial information relating to the Company’s operations by geographic area for the years ended December 31 is as follows (in millions): Sales 2015 2014 2013 United States (a) $ 834.6 $ 975.2 $ 774.3 Canada 198.4 260.0 256.7 United Kingdom 56.8 41.2 87.1 Other 8.9 6.1 11.5 Total sales $ 1,098.7 $ 1,282.5 $ 1,129.6 (a) United States sales exclude product sold to foreign customers at U.S. ports. Financial information relating to the Company’s long-lived assets, including deferred financing costs and other long-lived assets but excluding the investments related to the nonqualified retirement plan, by geographic area as of December 31 (in millions): Long-Lived Assets 2015 2014 United States $ 502.1 $ 420.0 Canada 394.3 413.7 United Kingdom 95.7 92.3 Brazil 116.4 — Other 6.5 6.6 Total long-lived assets $ 1,115.0 $ 932.6

EARNINGS PER SHARE (Tables)

EARNINGS PER SHARE (Tables)	12 Months Ended
	Dec. 31, 2015
Earnings Per Share [Abstract]
Earnings per share	The following table sets forth the computation of basic and diluted earnings per common share (in millions, except for share and per share data): Year ended December 31, 2015 2014 2013 Numerator: Net earnings $ 159.2 $ 217.9 $ 130.8 Less: Net earnings allocated to participating securities (a) (1.0 ) (1.5 ) (1.0 ) Net earnings available to common shareholders $ 158.2 $ 216.4 $ 129.8 Denominator (in thousands): Weighted average common shares outstanding, shares for basic earnings per share (b) 33,677 33,557 33,403 Weighted average equity awards outstanding 15 24 17 Shares for diluted earnings per share 33,692 33,581 33,420 Net earnings per common share, basic $ 4.70 $ 6.45 $ 3.89 Net earnings per common share, diluted $ 4.69 $ 6.44 $ 3.88 (a) Participating securities include options, PSUs and RSUs that receive non-forfeitable dividends. Net earnings were allocated to participating securities of 198,000 , 227,000 and 250,000 for 2015 , 2014 and 2013 , respectively. (b) For the calculation of diluted earnings per share, the Company uses the more dilutive of either the treasury stock method or the two-class method, to determine the weighted average number of outstanding common shares. In addition, the Company had 432,000 , 381,000 and 455,000 weighted options outstanding for 2015 , 2014 and 2013 , respectively, which were anti-dilutive and therefore not included in the diluted earnings per share calculation.

QUARTERLY RESULTS (Unaudited) (

QUARTERLY RESULTS (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2015
Quarterly Financial Data [Abstract]
Quarterly information	Quarter First Second Third Fourth 2015 Sales $ 393.0 $ 183.7 $ 232.7 $ 289.3 Gross profit 113.2 50.6 68.0 98.3 Net earnings 60.6 13.2 27.0 58.4 Net earnings per share, basic 1.79 0.39 0.80 1.72 Net earnings per share, diluted 1.79 0.39 0.80 1.72 Basic weighted-average shares outstanding (in thousands) 33,626 33,682 33,696 33,701 Diluted weighted-average shares outstanding (in thousands) 33,649 33,701 33,708 33,714 2014 Sales $ 422.0 $ 186.6 $ 240.5 $ 433.4 Gross profit (a) 92.3 37.5 149.8 141.8 Net earnings (loss) (a) 50.2 (0.7 ) 87.9 80.5 Net earnings (loss) per share, basic 1.49 (0.02 ) 2.60 2.38 Net earnings (loss) per share, diluted 1.49 (0.02 ) 2.60 2.38 Basic weighted-average shares outstanding (in thousands) 33,502 33,549 33,575 33,600 Diluted weighted-average shares outstanding (in thousands) 33,520 33,549 33,601 33,617 (a) In the third quarter of 2014 , the Company recognized a gain of $83.3 million ( $60.6 million , net of taxes) from an insurance settlement relating to damage it sustained as a result of a tornado that struck its rock salt mine and evaporation plan in Goderich, Ontario, in 2011. The Company recognized $82.3 million of the gain in product cost and $1.0 million of the gain in selling, general and administrative expenses in the consolidated statements of operations. In the second quarter of 2014 , the Company incurred costs of $6.9 million ( $5.1 million , net of taxes) related to the refinancing of its 8% Senior Notes with 4.875% Senior Notes.

SUMMARY OF SIGNIFICANT ACCOUN43

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Additional Information) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Foreign Currency [Abstract]
Loss on foreign exchange of intercompany notes of long-term nature	$ (33.7)	$ (18.4)	$ (15)
Foreign currency exchange income	13.9	6.6	$ 4.9
Environmental Costs [Abstract]
Environmental accrual	$ 1.4	$ 1.5
Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful lives of intangible assets	5 years
Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful lives of intangible assets	50 years

SUMMARY OF SIGNIFICANT ACCOUN44

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Property, Plant, & Equipment) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2015USD ($)extension_period	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)
Property, Plant and Equipment [Line Items]
Capitalized computer software costs	$ 28	$ 16.9
Period of amortization of capitalized computer software costs	5 years
Amortization of capitalized computer software costs	$ 2.2	$ 1.6	$ 1.3
Land Improvements [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	10 years
Land Improvements [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	25 years
Buildings and Structures [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	10 years
Buildings and Structures [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	30 years
Leasehold and Building Improvements [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	5 years
Leasehold and Building Improvements [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	40 years
Machinery and Equipment - Vehicles [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	3 years
Machinery and Equipment - Vehicles [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	10 years
Machinery and Equipment - Other Mining and Production [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	3 years
Machinery and Equipment - Other Mining and Production [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	50 years
Office Furniture and Equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	3 years
Office Furniture and Equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	10 years
Mineral Interests [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	81 years
Mineral Interests [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	20 years
Mineral Interests [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	99 years
Cote Blanche Mine [Member]
Property, Plant and Equipment [Line Items]
Lease expiration date	Dec. 31, 2060
Number of renewal periods | extension_period	2
Lease renewal period	25 years
Goderich Mine [Member]
Property, Plant and Equipment [Line Items]
Lease expiration date	Dec. 31, 2022
Lease renew date	Dec. 31, 2043
Other Mineral Properties [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	42 years
Typical Maximum Life Leasehold and Building Improvements [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	5 years
Typical Maximum Life Leasehold and Building Improvements [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	20 years
Inventories [Member] | Other Current Assets [Member]
Property, Plant and Equipment [Line Items]
Assets held-for-sale	$ 2.7
Property, Plant and Equipment [Member] | Other Current Assets [Member]
Property, Plant and Equipment [Line Items]
Assets held-for-sale	2.8
Water Rights [Member] | Other Current Assets [Member]
Property, Plant and Equipment [Line Items]
Assets held-for-sale	$ 5.2

SUMMARY OF SIGNIFICANT ACCOUN45

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Other Noncurrent Assets) (Details) - USD ($)	1 Months Ended		12 Months Ended
	Jun. 30, 2014	Dec. 31, 2013	Dec. 31, 2014	Dec. 31, 2015
Other Noncurrent Assets [Abstract]
Deferred financing costs			$ 8,500,000	$ 8,500,000
Accumulated amortization of deferred financing costs			2,700,000	3,900,000
Total charges related to refinancing	$ 8,100,000
Deferred financing costs related to refinancing fees	4,100,000	$ 600,000
Debt Instrument [Line Items]
Write off of deferred financing costs, due to refinancing	1,400,000
Write-off of debt issuance discount	1,500,000
Inventories of spare parts related to long term assets			13,700,000	11,000,000
Investments in marketable securities relating to deferred compensation arrangement			$ 1,900,000	1,600,000
4.875% Senior Notes [Member]
Debt Instrument [Line Items]
Face amount	250,000,000			$ 250,000,000
Stated interest rate			4.875%	4.875%
Write off of deferred financing costs, due to refinancing	1,400,000
Write-off of debt issuance discount	1,500,000
8% Senior Notes [Member]
Debt Instrument [Line Items]
Face amount				$ 100,000,000
Stated interest rate				8.00%
Call premium related to refinancing	$ 4,000,000		$ 4,000,000

EQUITY INVESTMENT (Details)

EQUITY INVESTMENT (Details) BRL in Millions, $ in Millions	1 Months Ended		12 Months Ended
	Dec. 31, 2015USD ($)	Dec. 31, 2015BRL	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)
Schedule of Equity Method Investments [Line Items]
Aggregate purchase price			$ 116.4	$ 0	$ 0
Investment in equity investee	$ 116.4		116.4	$ 0
Term Loan [Member] | Term Loan E Due May 2017 [Member]
Schedule of Equity Method Investments [Line Items]
Face amount	$ 100		100
Produquímica [Member]
Schedule of Equity Method Investments [Line Items]
Percentage of interest acquired	35.00%	35.00%
Aggregate purchase price	$ 114.1	BRL 452.4
Investment in equity investee	116.4		116.4
Transaction costs	2.3		2.3
Produquímica [Member] | Term Loan [Member] | Term Loan E Due May 2017 [Member]
Schedule of Equity Method Investments [Line Items]
Face amount	$ 100		$ 100
Produquímica [Member] | Common Stock [Member]
Schedule of Equity Method Investments [Line Items]
Percentage of interest acquired	6.00%	6.00%
Produquímica [Member] | Preferred Stock [Member]
Schedule of Equity Method Investments [Line Items]
Percentage of interest acquired	29.00%	29.00%

GODERICH TORNADO (Details)

GODERICH TORNADO (Details) - USD ($) $ in Millions	3 Months Ended	41 Months Ended
	Sep. 30, 2014	Dec. 31, 2014
Goderich Tornado [Abstract]
Total insurance advances		$ 114.9
Deferred revenue released in connection with settlement	$ 83.3
Gain recorded as reduction to production cost	82.3
Gain recorded as reduction to selling, general and administrative expenses	$ 1

INVENTORIES (Details)

INVENTORIES (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Inventory Disclosure [Abstract]
Finished goods	$ 223.1	$ 148.5
Raw materials and supplies	52.2	50.5
Total inventories	$ 275.3	$ 199

PROPERTY PLANT AND EQUIPMENT (D

PROPERTY PLANT AND EQUIPMENT (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 1,435.3	$ 1,327.3
Less accumulated depreciation and depletion	(634.6)	(626.4)
Property, plant and equipment, net	800.7	700.9
Land, Buildings and Structures and Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	347.3	352.2
Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	701.5	669.1
Office Furniture and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	25.4	17.5
Mineral Interests [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	169.6	179.6
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 191.5	$ 108.9

GOODWILL AND OTHER INTANGIBLE50

GOODWILL AND OTHER INTANGIBLE ASSETS (Schedule of Finite-Lived Intangible Assets) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Gross intangible asset	$ 77.8	$ 88.1
Accumulated amortization	(20.5)	(17.3)
Net intangible assets	57.3	70.8
Supply Agreement [Member]
Finite-Lived Intangible Assets [Line Items]
Gross intangible asset	26.1	31.3
Accumulated amortization	(2.6)	(2.5)
Net intangible assets	23.5	28.8
SOP Production Rights [Member]
Finite-Lived Intangible Assets [Line Items]
Gross intangible asset	24.3	24.3
Accumulated amortization	(11.7)	(10.8)
Net intangible assets	12.6	13.5
Customer and Distributor Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross intangible asset	7	8.1
Accumulated amortization	(2.5)	(2)
Net intangible assets	4.5	6.1
Lease Rights [Member]
Finite-Lived Intangible Assets [Line Items]
Gross intangible asset	1.6	1.9
Accumulated amortization	(0.2)	(0.2)
Net intangible assets	1.4	1.7
Patents [Member]
Finite-Lived Intangible Assets [Line Items]
Gross intangible asset	14.9	17.9
Accumulated amortization	(2.3)	(1.2)
Net intangible assets	12.6	16.7
Other [Member]
Finite-Lived Intangible Assets [Line Items]
Gross intangible asset	3.9	4.6
Accumulated amortization	(1.2)	(0.6)
Net intangible assets	$ 2.7	$ 4

GOODWILL AND OTHER INTANGIBLE51

GOODWILL AND OTHER INTANGIBLE ASSETS (Schedule of Estimated Useful Life) (Details)	12 Months Ended
	Dec. 31, 2015
Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful lives of intangible assets	5 years
Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful lives of intangible assets	50 years
Supply Agreement [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful lives of intangible assets	50 years
SOP Production Rights [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful lives of intangible assets	25 years
Patents [Member] | Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful lives of intangible assets	10 years
Patents [Member] | Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful lives of intangible assets	20 years
Developed Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful lives of intangible assets	5 years
Lease Rights [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful lives of intangible assets	25 years
Customer and Distributor Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful lives of intangible assets	10 years
Trademarks [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful lives of intangible assets	10 years
Noncompete Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful lives of intangible assets	5 years

GOODWILL AND OTHER INTANGIBLE52

GOODWILL AND OTHER INTANGIBLE ASSETS (Additional Information) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Finite-Lived Intangible Assets [Line Items]
Amortization expense	$ 4.4	$ 4.3	$ 2
Projected amortization expense over the next 5 years [Abstract]
Projected amortization expense, minimum	3.5
Projected amortization expense, maximum	$ 4.1
Weighted average amortization period	29 years
Acquired Indefinite-lived Intangible Assets [Line Items]
Goodwill	$ 58.1	68.5
Plant Nutrition [Member]
Acquired Indefinite-lived Intangible Assets [Line Items]
Goodwill	51.7	62
Water Rights [Member]
Acquired Indefinite-lived Intangible Assets [Line Items]
Indefinite-lived intangible assets	17.7	22.9
Trade Name [Member]
Acquired Indefinite-lived Intangible Assets [Line Items]
Indefinite-lived intangible assets	$ 10.3	$ 12.4
Minimum [Member]
Projected amortization expense over the next 5 years [Abstract]
Remaining amortization period	5 years
Other Current Assets [Member] | Water Rights [Member]
Acquired Indefinite-lived Intangible Assets [Line Items]
Assets held-for-sale	$ 5.2

INCOME TAXES (Additional Inform

INCOME TAXES (Additional Information) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating Loss Carryforwards [Line Items]
Valuation allowance	$ 0.9	$ 0.9	$ 1
Unrecognized tax benefits that would impact the effective tax rate	9.3	9.3
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Reductions due to expiration of tax years	2.7	2.7	$ 3.4	$ 0
Resolution with Various Taxing Authorities [Member]
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Significant decrease in unrecognized Tax Benefits	(0.8)	$ (0.8)
U.S. Federal [Member]
Income Tax Contingency [Line Items]
Years open and subject to examination		2,012
State [Member]
Income Tax Contingency [Line Items]
Years open and subject to examination		2,003
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	0.2	$ 0.2
Expiration dates		Dec. 31, 2033
Foreign Country, Expire 2033 [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	1.7	$ 1.7
Expiration dates		Dec. 31, 2033
Foreign [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	$ 3.6	$ 3.6

INCOME TAXES INCOME TAXES (Inco

INCOME TAXES INCOME TAXES (Income Tax Provision (Benefit)) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current:
Federal	$ 31.7	$ 37.4	$ 23.2
State	7.3	9.5	5.7
Foreign	16.4	23.4	14.6
Total current	55.4	70.3	43.5
Deferred:
Federal	(0.2)	(3.6)	(2.5)
State	0	(0.9)	(0.6)
Foreign	0.1	8.1	2.9
Total deferred	(0.1)	3.6	(0.2)
Total provision for income taxes	$ 55.3	$ 73.9	$ 43.3

INCOME TAXES INCOME TAXES (Comp

INCOME TAXES INCOME TAXES (Components of Earnings Before Taxes and Tax Effect) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Domestic income	$ 170.6	$ 184.3	$ 112.3
Foreign income	43.9	107.5	61.8
Earnings before income taxes	214.5	291.8	174.1
Computed tax at the U.S. federal statutory rate of 35%	75.1	102.1	60.9
Foreign income rate differential, mining, and withholding taxes, net of U.S. federal deduction	(1.2)	(9.3)	(2.6)
Percentage depletion in excess of basis	(11.2)	(11.8)	(9)
Other domestic tax reserves, net of reversals	(4.5)	(3.9)	(0.9)
Domestic manufacturers deduction	(2.4)	(2.5)	(1.3)
State income taxes, net of federal income tax benefit	5.1	5.5	3.4
Interest expense recognition differences	(6.1)	(7.1)	(7)
Other, net	0.5	0.9	(0.2)
Total provision for income taxes	$ 55.3	$ 73.9	$ 43.3
Effective tax rate	26.00%	25.00%	25.00%
Federal statutory tax rate	35.00%	35.00%	35.00%

INCOME TAXES INCOME TAXES (Co56

INCOME TAXES INCOME TAXES (Components of Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Current deferred tax assets:
Accrued expenses	$ 0	$ 3.5
Other, net	0	6.2
Current deferred tax assets	0	9.7
Current deferred tax liabilities:
Other, net	0	0.4
Current deferred tax liabilities	0	0.4
Noncurrent deferred taxes:
Property, plant and equipment	73	77.6
Intangible asset	13.9	17.7
Other, net	3.3	2.7
Total noncurrent deferred tax liabilities	90.2	98
Deferred tax assets:
Net operating loss carryforwards	2.6	0.8
Stock-based compensation	4.7	3.7
Other, net	12.5	5.6
Subtotal	19.8	10.1
Valuation allowance	(0.9)	(1)
Total noncurrent deferred tax assets	18.9	9.1
Net noncurrent deferred tax liabilities	$ 71.3	$ 88.9

INCOME TAXES INCOME TAXES (Unre

INCOME TAXES INCOME TAXES (Unrecognized Tax Benefits) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Unrecognized tax benefits [Roll forward]
Balance at January 1		$ 21.8	$ 24.6	$ 25.3
Additions resulting from current year tax positions		1.6	1	1
Additions relating to tax positions taken in prior years		0.8	1.1	0
Reductions due to cash payments		(0.8)	(0.3)	(0.8)
Reductions relating to tax positions taken in prior years		(2.4)	(1.2)	(0.9)
Reductions due to expiration of tax years	$ (2.7)	(2.7)	(3.4)	0
Balance at December 31	$ 18.3	$ 18.3	$ 21.8	$ 24.6

INCOME TAXES INCOME TAXES (In58

INCOME TAXES INCOME TAXES (Income Tax Examination Additional Information) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Examination [Line Items]
Accruals of interest and penalties, net of reversals	$ 0.2	$ 0.6	$ 0.4
Accrued interest and penalties	4.2	$ 4.1
Total undistributed earnings on which no U.S. federal income tax has been provided	401
Cash and cash equivalents in foreign subsidiaries	54.4
Amount of security in the form of bank letter guarantees	44.1
Canadian Provincial [Member]
Income Tax Examination [Line Items]
Total reassessments including interest	77.7
Amount of security posted in the form of a performance bond	49.2
Amount of security posted in the form of cash	$ 27.3
Canadian Provincial [Member] | Minimum [Member]
Income Tax Examination [Line Items]
Year under examination	2,002
Canadian Provincial [Member] | Maximum [Member]
Income Tax Examination [Line Items]
Year under examination	2,010
Canadian Federal [Member]
Income Tax Examination [Line Items]
Amount of security posted in the form of a performance bond	$ 19.3
Total reassessment amount including penalty	87.1
Amount of security in the form of bank letter guarantees	$ 34.7
Canadian Federal [Member] | Minimum [Member]
Income Tax Examination [Line Items]
Year under examination	2,004
Canadian Federal [Member] | Maximum [Member]
Income Tax Examination [Line Items]
Year under examination	2,006
Canadian and Provincial [Member] | Tax Year 2007 Through 2008 [Member]
Income Tax Examination [Line Items]
Amount of security posted in the form of a performance bond	$ 8.6
Amount of security in the form of bank letter guarantees	9.4
Total amount of reassessment including penalties and interest	$ 30.8
Canadian and Provincial [Member] | Minimum [Member] | Tax Year 2007 Through 2008 [Member]
Income Tax Examination [Line Items]
Year under examination	2,007
Canadian and Provincial [Member] | Maximum [Member] | Tax Year 2007 Through 2008 [Member]
Income Tax Examination [Line Items]
Year under examination	2,008

PENSION PLANS AND OTHER BENEF59

PENSION PLANS AND OTHER BENEFITS (Additional Information) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Amounts recognized in accumulated other comprehensive income, net of tax [Abstract]
Other comprehensive income (loss) related to actuarial gains (losses), net of tax	$ 5.2	$ 0.3	$ 0.3
Other comprehensive income (loss) related to foreign exchange	(98.4)	(48)	(24.4)
Defined contribution and pre-tax savings plans [Abstract]
Expense attributable to all Savings Plans	$ 8.9	11.5	7.6
U.K. Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, year the plan closed to new participants	1,992
Defined Benefit Plan, date future benefits cease to accrue for remaining active employee participants	Dec. 1, 2008
Amounts recognized in accumulated other comprehensive income, net of tax [Abstract]
Actuarial net losses recognized in accumulated other comprehensive income, net of tax	$ 3.8	8.9
Accumulated other comprehensive income (loss) before adjustment of prior service costs	5.6	10.9
Accumulated other comprehensive income (loss) related to prior service cost net of tax	1.8	2
Other comprehensive income (loss) related to actuarial gains (losses), net of tax	3.7	(1.6)	(0.8)
Other comprehensive income (loss) related to amortization of loss, net of tax	1.2	1.4	1.5
Other comprehensive income (loss) related to prior service cost, net of tax	(0.1)	(0.1)	(0.1)
Other comprehensive income (loss) related to foreign exchange	0.4	0.6	(0.2)
Expected losses to be recognized in net periodic benefit costs in next fiscal year	0.3
Expected amortization of gain (losses) in next fiscal year	0.4
Expected amortization of prior service cost in next fiscal year	0.1
Net periodic (benefit) cost expected in next fiscal year	(0.2)
Estimated employer contributions, next fiscal year [Abstract]
Estimated employer contributions, next fiscal year	1.5
Amounts recognized in balance sheet [Abstract]
Underfunded plan status recorded in accrued expenses		1.6
Underfunded plan status recorded in noncurrent liabilities		4.9
Accumulated benefit obligation	$ 66.9	76.8
Period of amortization of pension benefit obligations	5 years
Defined contribution and pre-tax savings plans [Abstract]
Investments in marketable securities relating to deferred compensation arrangement	$ 1.6	1.9
Compensation expense (reduction) recorded for deferred compensation arrangement	$ 0.1	0.1	0.5
Investment income on deferred compensation arrangement		$ 0.1	$ 0.4
U.K. Pension Plan [Member] | Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Target allocation (in hundredths)	75.00%
U.K. Pension Plan [Member] | Bond Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Target allocation (in hundredths)	25.00%

PENSION PLANS AND OTHER BENEF60

PENSION PLANS AND OTHER BENEFITS (Weighted-Average Asset Allocations and Fair Value of Plan Assets) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Weighted-average asset allocation	100.00%	100.00%
Fair value of pension plan assets [Abstract]
Total Pension Assets	$ 66.9	$ 70.3
Level One [Member]
Fair value of pension plan assets [Abstract]
Total Pension Assets	0.9	1
Level Two [Member]
Fair value of pension plan assets [Abstract]
Total Pension Assets	51.4	69.3
Level Three [Member]
Fair value of pension plan assets [Abstract]
Total Pension Assets	$ 14.6	$ 0
Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted-average asset allocation	1.00%	1.00%
Fair value of pension plan assets [Abstract]
Total Pension Assets	$ 0.9	$ 1
Cash and Cash Equivalents [Member] | Level One [Member]
Fair value of pension plan assets [Abstract]
Total Pension Assets	0.9	1
Cash and Cash Equivalents [Member] | Level Two [Member]
Fair value of pension plan assets [Abstract]
Total Pension Assets	0	0
Cash and Cash Equivalents [Member] | Level Three [Member]
Fair value of pension plan assets [Abstract]
Total Pension Assets	$ 0	$ 0
Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted-average asset allocation	0.00%	53.00%
Fair value of pension plan assets [Abstract]
Total Pension Assets	$ 0	$ 37
Equity Funds [Member] | Level One [Member]
Fair value of pension plan assets [Abstract]
Total Pension Assets	0	0
Equity Funds [Member] | Level Two [Member]
Fair value of pension plan assets [Abstract]
Total Pension Assets	0	37
Equity Funds [Member] | Level Three [Member]
Fair value of pension plan assets [Abstract]
Total Pension Assets	$ 0	$ 0
Blended Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted-average asset allocation	32.00%	0.00%
Fair value of pension plan assets [Abstract]
Total Pension Assets	$ 21.1
Blended Funds [Member] | Level One [Member]
Fair value of pension plan assets [Abstract]
Total Pension Assets	0
Blended Funds [Member] | Level Two [Member]
Fair value of pension plan assets [Abstract]
Total Pension Assets	21.1
Blended Funds [Member] | Level Three [Member]
Fair value of pension plan assets [Abstract]
Total Pension Assets	$ 0
Bond Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted-average asset allocation	45.00%	46.00%
Bond Funds: Treasuries [Member]
Fair value of pension plan assets [Abstract]
Total Pension Assets	$ 30.3	$ 32.3
Bond Funds: Treasuries [Member] | Level One [Member]
Fair value of pension plan assets [Abstract]
Total Pension Assets	0	0
Bond Funds: Treasuries [Member] | Level Two [Member]
Fair value of pension plan assets [Abstract]
Total Pension Assets	30.3	32.3
Bond Funds: Treasuries [Member] | Level Three [Member]
Fair value of pension plan assets [Abstract]
Total Pension Assets	$ 0	$ 0
Insurance Policy [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted-average asset allocation	22.00%	0.00%
Fair value of pension plan assets [Abstract]
Total Pension Assets	$ 14.6
Insurance Policy [Member] | Level One [Member]
Fair value of pension plan assets [Abstract]
Total Pension Assets	0
Insurance Policy [Member] | Level Two [Member]
Fair value of pension plan assets [Abstract]
Total Pension Assets	0
Insurance Policy [Member] | Level Three [Member]
Fair value of pension plan assets [Abstract]
Total Pension Assets	$ 14.6

PENSION PLANS AND OTHER BENEF61

PENSION PLANS AND OTHER BENEFITS (Summary of Changes in Level 3 Pension Plan Assets) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan, Change In Fair Value Of Plan Assets, Level 3 Reconciliation [Roll Forward]
Fair value as of January 1	$ 70.3	$ 66.7
Currency fluctuation adjustment	(3.9)	(4.3)
Fair value of plan assets as of December 31	66.9	70.3
Pension Plan [Member] | Level Three [Member]
Defined Benefit Plan, Change In Fair Value Of Plan Assets, Level 3 Reconciliation [Roll Forward]
Fair value as of January 1	0
Purchase	15.4
Unrealized loss	(0.1)
Currency fluctuation adjustment	(0.7)
Fair value of plan assets as of December 31	$ 14.6	$ 0

PENSION PLANS AND OTHER BENEF62

PENSION PLANS AND OTHER BENEFITS (Summary of Assumptions Used in Calculating Net Periodic Benefit Costs) (Details)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Assumptions used in calculating net periodic benefit cost [Abstract]
Discount rate	3.40%	4.40%	4.40%
Expected return on plan assets	4.30%	5.30%	4.60%

PENSION PLANS AND OTHER BENEF63

PENSION PLANS AND OTHER BENEFITS (Summary of Future Expected Benefit Payments) (Details) $ in Millions	Dec. 31, 2015USD ($)
Future expected benefit payments [Abstract]
2,016	$ 2.8
2,017	2.9
2,018	3
2,019	3.1
2,020	3.2
2021-2025	$ 17.4

PENSION PLANS AND OTHER BENEF64

PENSION PLANS AND OTHER BENEFITS (Summary of Changes in Benefit Obligation and Plan Assets) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Change in benefit obligation:
Benefit obligation as of January 1	$ 76.8	$ 73.6
Interest cost	2.5	3.2	$ 3
Actuarial (gain) loss	(5.5)	7.6
Benefits paid	(2.9)	(2.9)
Currency fluctuation adjustment	(4)	(4.7)
Benefit obligation as of December 31	66.9	76.8	73.6
Change in plan assets:
Fair value as of January 1	70.3	66.7
Actual return	1.9	9.2
Company contributions	1.5	1.6
Currency fluctuation adjustment	(3.9)	(4.3)
Benefits paid	(2.9)	(2.9)
Fair value of plan assets as of December 31	66.9	70.3	$ 66.7
Underfunded status of the plan	$ 0	$ (6.5)

PENSION PLANS AND OTHER BENEF65

PENSION PLANS AND OTHER BENEFITS (Summary of Components of Net Pension Expense) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Components of net pension expense [Abstract]
Interest cost on projected benefit obligation	$ 2.5	$ 3.2	$ 3
Prior service cost	(0.1)	(0.1)	(0.1)
Expected return on plan assets	(2.9)	(3.5)	(2.8)
Net amortization	1.5	1.7	1.8
Net pension expense	$ 1	$ 1.3	$ 1.9

LONG TERM DEBT (Additional Info

LONG TERM DEBT (Additional Information) (Details) - USD ($)	1 Months Ended			3 Months Ended	12 Months Ended
	Dec. 31, 2015	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2014	Dec. 31, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Debt issuance costs				$ 6,900,000
Long-term Debt	$ 727,000,000				$ 727,000,000	$ 626,400,000
Write-off of deferred financing fees		$ 1,400,000
Write-off of debt issuance discount		1,500,000
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity			$ 125,000,000
Deferred financing costs			$ 600,000
Amount of facility that may be drawn in Canadian dollars	40,000,000				40,000,000
Amount of facility that may be drawn in British pounds sterling	10,000,000				10,000,000
Sub-limit for short-term letters of credit	50,000,000				50,000,000
Long-term Debt	4,500,000				4,500,000	0
Outstanding letters of credit	5,600,000				5,600,000
Available borrowing capacity	114,900,000				114,900,000
Credit Agreement [Member]
Debt Instrument [Line Items]
Face amount	$ 477,000,000				$ 477,000,000
Description of variable rate basis					Either the Eurodollar rate ("LIBOR") or a base rate (defined as the greater of a specified U.S. or Canadian prime lending rate or the federal funds effective rate, increased by 0.5%) plus a margin
Interest spread over base rate (in hundredths)			0.50%
Weighted average interest rate on all borrowings outstanding (in hundredths)	2.10%				2.10%
Senior Notes [Member]
Debt Instrument [Line Items]
Face amount	$ 100,000,000				$ 100,000,000
Stated interest rate	8.00%				8.00%
Call premium related to refinancing		4,000,000				4,000,000
Term Loan E Due May 2017 [Member] | Term Loan [Member]
Debt Instrument [Line Items]
Face amount	$ 100,000,000				$ 100,000,000
Term Loan E Due May 2017 [Member] | Term Loan [Member] | Other Expense [Member]
Debt Instrument [Line Items]
Debt issuance costs					300,000
4.875% Senior Notes [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Deferred financing costs		4,100,000		4,100,000
Long-term Debt	$ 250,000,000	$ 250,000,000		$ 250,000,000	$ 250,000,000	$ 250,000,000
Stated interest rate	4.875%	4.875%		4.875%	4.875%	4.875%
Refinancing fees		$ 8,100,000
8% Senior Notes July 2019 [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Outstanding principal amount redeemed		$ 100,000,000
Produquímica [Member]
Debt Instrument [Line Items]
Percentage of interest acquired	35.00%
Produquímica [Member] | Term Loan E Due May 2017 [Member] | Term Loan [Member]
Debt Instrument [Line Items]
Face amount	$ 100,000,000				$ 100,000,000
LIBOR [Member] | Credit Agreement [Member]
Debt Instrument [Line Items]
Interest spread over base rate (in hundredths)					1.75%
LIBOR [Member] | Term Loan E Due May 2017 [Member] | Term Loan [Member] | Line of Credit [Member]
Debt Instrument [Line Items]
Interest spread over base rate (in hundredths)					1.75%

LONG TERM DEBT (Summary of Long

LONG TERM DEBT (Summary of Long-Term Debt) (Details) - USD ($)	Dec. 31, 2015	Dec. 31, 2014	Jun. 30, 2014
Debt Instrument [Line Items]
Long-term debt, total	$ 727,000,000	$ 626,400,000
Less current portion	(4,900,000)	(3,900,000)
Long-term debt	722,100,000	622,500,000
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Long-term debt, total	4,500,000	0
Term Loan [Member] | Term Loan due May 2017 [Member]
Debt Instrument [Line Items]
Long-term debt, total	$ 472,500,000	376,400,000
Senior Notes [Member]
Debt Instrument [Line Items]
Stated interest rate	8.00%
Senior Notes [Member] | 4.875% Senior Notes due July 2024 [Member]
Debt Instrument [Line Items]
Long-term debt, total	$ 250,000,000	$ 250,000,000	$ 250,000,000
Stated interest rate	4.875%	4.875%	4.875%

LONG TERM DEBT (Future Maturiti

LONG TERM DEBT (Future Maturities of Long-Term Debt) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Future maturities of long-term debt [Abstract]
2,016	$ 4.9
2,017	472.1
2,018	0
2,019	0
2,020	0
Thereafter	250
Long-term debt, total	$ 727	$ 626.4

DERIVATIVES AND FAIR VALUES O69

DERIVATIVES AND FAIR VALUES OF FINANCIAL INSTRUMENTS (Details) - Commodity Contract [Member] MMBTU in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2015USD ($)MMBTU	Dec. 31, 2014MMBTU
Derivatives, Fair Value [Line Items]
Underlying risk	change in natural gas prices
Period through which natural gas is hedged	Dec. 1, 2017
Percent of forecasted usage to be hedged (in hundredths)	90.00%
Maximum period which the Company hedges in advance of forecasted purchase (in months)	36 months
Notional amount (in MMBtus) | MMBTU	2.8	3.4
Net gain (loss) to be reclassified from accumulated other comprehensive income to earnings during the next 12 months | $	$ (2.5)

DERIVATIVES AND FAIR VALUES O70

DERIVATIVES AND FAIR VALUES OF FINANCIAL INSTRUMENTS (Fair Value of Hedged Items) (Details) $ in Millions	Dec. 31, 2015USD ($)counterparty	Dec. 31, 2014USD ($)counterparty
Derivatives, Fair Value [Line Items]
Number of counterparties | counterparty	2	4
Number of counterparties for amounts recorded as assets | counterparty		2
Commodity Contract [Member]
Derivatives, Fair Value [Line Items]
Netting of contracts in a receivable position against contracts in payable position	$ 0.1	$ 0.1
Derivatives Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives	0.1	0.1
Liability Derivatives	2.7	3.5
Derivatives Designated as Hedging Instruments [Member] | Commodity Contract [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives	0.1	0.1
Derivatives Designated as Hedging Instruments [Member] | Commodity Contract [Member] | Accrued Expenses [Member]
Derivatives, Fair Value [Line Items]
Liability Derivatives	2.6	2.5
Derivatives Designated as Hedging Instruments [Member] | Commodity Contract [Member] | Other Assets [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives	0	0
Derivatives Designated as Hedging Instruments [Member] | Commodity Contract [Member] | Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Liability Derivatives	$ 0.1	$ 1

DERIVATIVES AND FAIR VALUES O71

DERIVATIVES AND FAIR VALUES OF FINANCIAL INSTRUMENTS (Activity Related to Other Comprehensive Income) (Details) - Derivatives in Cash Flow Hedging Relationships [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (Gain) Loss Recognized in OCI on Derivative (Effective Portion)	$ 2.4	$ 2.8
Amount of Gain (Loss) Reclassified from Accumulated OCI Into Income (Effective Portion)	(3.1)	1
Commodity Contract [Member] | Product Cost [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (Gain) Loss Recognized in OCI on Derivative (Effective Portion)	2.4	2.8
Amount of Gain (Loss) Reclassified from Accumulated OCI Into Income (Effective Portion)	$ (3.1)	$ 1

COMMITMENTS AND CONTINGENCIES72

COMMITMENTS AND CONTINGENCIES (Additional Information) (Details) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2015USD ($)	Dec. 31, 2013USD ($)	Dec. 31, 2015USD ($)agreement	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)
Unions [Abstract]
Percentage of company's U.S. workforce represented by labor unions (in hundredths)			30.00%
Percentage of company's global workforce represented by labor unions (in hundredths)			50.00%
Number of collective bargaining agreements | agreement			12
Number of collective bargaining agreements expiring in 2016 | agreement			3
Percentage of company's global workforce with collective bargaining agreements expiring in 2015 (in hundredths)			6.00%
Number of collective bargaining agreements expiring in 2017 | agreement			4
Number of collective bargaining agreements expiring in year 2018 | agreement			4
Number of collective bargaining agreements expiring in year 2019 | agreement			1
Percentage of workforce employed in Europe (in hundredths)			10.00%
Royalties [Abstract]
Royalty expense			$ 14	$ 17.8	$ 14.7
Sales contracts [Abstract]
Guarantor obligations, performance bonds outstanding			106.7
Amount of security in the form of bank letter guarantees			44.1
Purchase commitments [Abstract]
Purchase commitments for 2016			57.6
Annual purchase commitments for 2017 through 2020, minimum			32.5
Annual purchase commitments for 2017 through 2020, maximum			$ 35
Labor Dispute [Member]
Loss Contingencies [Line Items]
Contingency reserve		$ 5
Increase in contingency reserve	$ 2

COMMITMENTS AND CONTINGENCIES C

COMMITMENTS AND CONTINGENCIES COMMITMENTS AND CONTINGENCIES (Schedule of Operating Leases) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Commitments and Contingencies Disclosure [Abstract]
2,016	$ 15.7
2,017	9.7
2,018	4.1
2,019	3.6
2,020	1.9
Thereafter	5
Total	40
Rental expense, net of sublease income	$ 20.7	$ 18.6	$ 17.1

STOCKHOLDERS' EQUITY AND EQUI74

STOCKHOLDERS' EQUITY AND EQUITY INSTRUMENTS (Summary of Plan Information) (Details)	3 Months Ended				12 Months Ended
	Dec. 31, 2015$ / sharesshares	Sep. 30, 2014$ / shares	Jun. 30, 2014$ / shares	Mar. 31, 2014$ / shares	Dec. 31, 2015award_type$ / sharesshares	Dec. 31, 2014$ / sharesshares	Dec. 31, 2013$ / sharesshares	May. 31, 2015shares	Dec. 31, 2005shares
Stockholders' Equity and Equity Instruments [Abstract]
Dividends paid (in dollars per share) | $ / shares	$ 0.66	$ 0.66	$ 0.66	$ 0.66	$ 2.64	$ 2.40	$ 2.18
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of PSU types granted | award_type					2
RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)					21,317	20,268	65,521
PSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)					35,584	27,574	29,134
Performance period					3 years
Deferred Compensation Arrangement [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Deferred stock units credited in period (in shares)					12,542	14,340	16,331
Deferred Compensation Arrangement [Member] | Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reissued from treasury stock (in shares)					31,954	976	1,259
2005 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Authorized shares (in shares)									3,240,000
2005 Plan [Member] | Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award expiration description					Unexercised options expire after seven years.
Service period					4 years
Terms of award					Upon vesting, each option can be exercised to purchase one share of the Company’s common stock.
2005 Plan [Member] | Stock Options [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award expiration period					7 years
2005 Plan [Member] | RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period					3 years
Service period					3 years
Number of shares available for each vested RSU	1				1
Terms of award					One share of common stock for each vested RSU.
2005 Plan [Member] | PSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period					3 years
Service period					3 years
Performance period					3 years
Minimum percentage of earnings (in hundredths)					0.00%
Maximum percentage of earnings (in hundredths)					200.00%
2015 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Authorized shares (in shares)								3,000,000
Options granted					0
2015 Plan [Member] | RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period					3 years
Service period					3 years
2015 Plan [Member] | PSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)					0

STOCKHOLDERS' EQUITY AND EQUI75

STOCKHOLDERS' EQUITY AND EQUITY INSTRUMENTS (Summary of Activity) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Stock Options [Member]
Stock option activity
Outstanding at beginning of period (in shares)	278,429	328,364	435,721
Granted (in shares)	120,956	95,610	124,370
Exercised (in shares)	(33,906)	(112,005)	(174,149)
Cancelled/Expired (in shares)	(12,392)	(33,540)	(57,578)
Outstanding at end of period (in shares)	353,087	278,429	328,364
Stock option weighted-average exercise price
Outstanding at beginning of period (in dollars per share)	$ 79.23	$ 72.88	$ 67.46
Granted (in dollars per share)	91.76	87.18	76.84
Exercised (in dollars per share)	72.53	67.35	60.71
Cancelled/Expired (in dollars per share)	84.71	79.81	77.19
Outstanding at end of period (in dollars per share)	$ 83.94	$ 79.23	$ 72.88
RSUs [Member]
RSU and PSU activity
Outstanding at beginning of period (in shares)	88,532	95,718	77,749
Granted (in shares)	21,317	20,268	65,521
Released from restriction (in shares)	(15,952)	(15,636)	(22,658)
Cancelled/Expired (in shares)	(2,889)	(11,818)	(24,894)
Outstanding at end of period (in shares)	91,008	88,532	95,718
RSU and PSU weighted-average fair value
Outstanding at beginning of period (in dollars per share)	$ 76.58	$ 76.09	$ 78.46
Granted (in dollars per share)	90.94	86.74	74.99
Released from restriction (in dollars per share)	71.69	86.48	78.46
Cancelled/Expired (in dollars per share)	81.43	76.95	78.42
Outstanding at end of period (in dollars per share)	$ 80.65	$ 76.58	$ 76.09
PSUs [Member]
RSU and PSU activity
Outstanding at beginning of period (in shares)	59,627	55,149	49,932
Granted (in shares)	35,584	27,574	29,134
Released from restriction (in shares)	(10,454)	(3,998)	(6,341)
Cancelled/Expired (in shares)	(7,392)	(19,098)	(17,576)
Outstanding at end of period (in shares)	77,365	59,627	55,149
RSU and PSU weighted-average fair value
Outstanding at beginning of period (in dollars per share)	$ 88.69	$ 80.89	$ 83.58
Granted (in dollars per share)	100.49	105.77	78.01
Released from restriction (in dollars per share)	74.49	93.82	86.51
Cancelled/Expired (in dollars per share)	82.46	89.77	81.72
Outstanding at end of period (in dollars per share)	$ 96.63	$ 88.69	$ 80.89
Shares expected to be issued in the next fiscal quarter (in shares)	9,914

STOCKHOLDERS' EQUITY AND EQUI76

STOCKHOLDERS' EQUITY AND EQUITY INSTRUMENTS (Summary of Preferred Stock) (Details)	Dec. 31, 2015shares
Preferred Stocks [Abstract]
Preferred stock, shares authorized (in shares)	10,000,000
Preferred stock, shares issued (in shares)	0
Preferred stock, shares outstanding (in shares)	0
Series A Preferred Stock [Member]
Preferred Stocks [Abstract]
Shares designated as series A junior participating preferred stock (in shares)	200,000

STOCKHOLDERS' EQUITY AND EQUI77

STOCKHOLDERS' EQUITY AND EQUITY INSTRUMENTS (Summary of Fair Value Assumptions and Methodology) (Details) - Stock Options [Member] - $ / shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of options granted (in dollars per share)	$ 14.78	$ 15.25	$ 19.06
Expected term (years)	4 years 9 months 18 days	4 years 9 months 18 days	4 years 8 months 12 days
Expected volatility	24.90%	27.80%	38.00%
Dividend yield	3.10%	3.40%	3.00%
Risk-free interest rates	1.60%	1.50%	0.90%

STOCKHOLDERS' EQUITY AND EQUI78

STOCKHOLDERS' EQUITY AND EQUITY INSTRUMENTS STOCKHOLDERS' EQUITY AND EQUITY INSTRUMENTS (Summary of Exercise Price Range) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options outstanding (in shares)	353,087	278,429
Weighted-average remaining contractual life of options outstanding	4 years 7 months 6 days
Weighted-average exercise price of options outstanding (in dollars per share)	$ 83.94
Options exercisable (in shares)	124,282
Weighted-average remaining contractual life of exercisable options	3 years 1 month 6 days
Weighted-average exercise price of exercisable options (in dollars per share)	$ 78.21
$52.84 - $76.10 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price range, lower range limit (in dollars per share)	58.99
Exercise price range, upper range limit (in dollars per share)	$ 77.75
Options outstanding (in shares)	114,116
Weighted-average remaining contractual life of options outstanding	3 years 8 months 12 days
Weighted-average exercise price of options outstanding (in dollars per share)	$ 74.16
Options exercisable (in shares)	63,633
Weighted-average remaining contractual life of exercisable options	3 years 4 months
Weighted-average exercise price of exercisable options (in dollars per share)	$ 72.74
$76.11 - $77.75 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price range, lower range limit (in dollars per share)	77.76
Exercise price range, upper range limit (in dollars per share)	$ 86.99
Options outstanding (in shares)	42,130
Weighted-average remaining contractual life of options outstanding	1 year 8 months 12 days
Weighted-average exercise price of options outstanding (in dollars per share)	$ 82.51
Options exercisable (in shares)	42,130
Weighted-average remaining contractual life of exercisable options	1 year 8 months 12 days
Weighted-average exercise price of exercisable options (in dollars per share)	$ 82.51
$77.76 - $86.99 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price range, lower range limit (in dollars per share)	87
Exercise price range, upper range limit (in dollars per share)	$ 89.47
Options outstanding (in shares)	79,717
Weighted-average remaining contractual life of options outstanding	5 years 2 months 12 days
Weighted-average exercise price of options outstanding (in dollars per share)	$ 87.18
Options exercisable (in shares)	18,445
Weighted-average remaining contractual life of exercisable options	5 years 2 months 12 days
Weighted-average exercise price of exercisable options (in dollars per share)	$ 87.18
$87.00 - $87.18 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price range, lower range limit (in dollars per share)	89.48
Exercise price range, upper range limit (in dollars per share)	$ 93.26
Options outstanding (in shares)	117,124
Weighted-average remaining contractual life of options outstanding	6 years 2 months 12 days
Weighted-average exercise price of options outstanding (in dollars per share)	$ 91.77
Options exercisable (in shares)	74
Weighted-average remaining contractual life of exercisable options	6 years 2 months 12 days
Weighted-average exercise price of exercisable options (in dollars per share)	$ 91.75

STOCKHOLDERS' EQUITY AND EQUI79

STOCKHOLDERS' EQUITY AND EQUITY INSTRUMENTS (Additional Information) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Equity compensation, additional general disclosures [Abstract]
Options outstanding (in shares)	353,087	278,429
Number of options outstanding that are exercisable (in shares)		99,425
Compensation expense related to stock-based compensation awards	$ 6.1	$ 4.9	$ 5.1
Unrecorded compensation cost related to non-vested awards	$ 6.6
Unrecorded compensation cost, weighted average period of recognition	2 years
Stock Options [Member]
Equity compensation, additional general disclosures [Abstract]
Number of options outstanding that are exercisable (in shares)	124,282
Fair value of options vested	$ 1.1	1.3	1.6
Intrinsic value of stock options exercised during the period	0.6	$ 2.3	$ 4.5
Intrinsic value of options outstanding	0.2
Intrinsic value of options exercisable	$ 0.2

STOCKHOLDERS' EQUITY AND EQUI80

STOCKHOLDERS' EQUITY AND EQUITY INSTRUMENTS (Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	$ (15.5)	$ 34.5
Other comprehensive income (loss) before reclassifications	(95.8)	(50.7)
Amounts reclassified from accumulated other comprehensive loss	3	0.7
Net current period other comprehensive income (loss)	(92.8)	(50)
Ending balance	(108.3)	(15.5)
Gains and (Losses) on Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(2)	0.3
Other comprehensive income (loss) before reclassifications	(1.5)	(1.7)
Amounts reclassified from accumulated other comprehensive loss	1.9	(0.6)
Net current period other comprehensive income (loss)	0.4	(2.3)
Ending balance	(1.6)	(2)
Defined Benefit Pension [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(9)	(9.3)
Other comprehensive income (loss) before reclassifications	4.1	(1)
Amounts reclassified from accumulated other comprehensive loss	1.1	1.3
Net current period other comprehensive income (loss)	5.2	0.3
Ending balance	(3.8)	(9)
Foreign Currency [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(4.5)	43.5
Other comprehensive income (loss) before reclassifications	(98.4)	(48)
Amounts reclassified from accumulated other comprehensive loss	0	0
Net current period other comprehensive income (loss)	(98.4)	(48)
Ending balance	$ (102.9)	$ (4.5)

STOCKHOLDERS' EQUITY AND EQUI81

STOCKHOLDERS' EQUITY AND EQUITY INSTRUMENTS (Amount Reclassified from AOCI) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Product cost									$ (507.1)	$ (523.4)	$ (541.9)
Income tax expense (benefit)									55.3	73.9	43.3
Total reclassifications, net of income taxes	$ 58.4	$ 27	$ 13.2	$ 60.6	$ 80.5	$ 87.9	$ (0.7)	$ 50.2	159.2	217.9	$ 130.8
Reclassifications, net of income taxes [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total reclassifications, net of income taxes									3	0.7
Reclassifications, net of income taxes [Member] | Gain and (losses) on cash flow hedges [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Product cost									3.1	(1)
Income tax expense (benefit)									(1.2)	0.4
Total reclassifications, net of income taxes									1.9	(0.6)
Reclassifications, net of income taxes [Member] | Amortization of defined benefit pension [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Product cost									1.4	1.6
Income tax expense (benefit)									(0.3)	(0.3)
Total reclassifications, net of income taxes									$ 1.1	$ 1.3

FAIR VALUE MEASUREMENTS (Summar

FAIR VALUE MEASUREMENTS (Summary of Estimated Fair Values) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Liability Class:
Mutual fund investments percentage of fund invested in common stock of large-cap U.S. (in hundredths)	20.00%	15.00%
Mutual fund investments percentage of fund invested in common stock of small cap To mid-cap U.S. (in hundredths)	5.00%
Mutual fund investments percentage of fund invested in common stock of international companies (in hundredths)	5.00%	5.00%
Mutual fund investments percentage of fund invested in debt securities (in hundredths)	5.00%	5.00%
Mutual fund investments percentage of fund invested in short-term investments (in hundredths)	35.00%	35.00%
Mutual fund investments percentage of fund invested in blended funds (in hundredths)	30.00%	40.00%
Fair Value, Measurements, Recurring [Member]
Asset Class:
Mutual fund investments in a non-qualified savings plan	$ 1.6	$ 1.9
Total Assets	1.6	1.9
Liability Class:
Liabilities related to non-qualified savings plan	(1.6)	(1.9)
Derivatives – natural gas instruments	(2.6)	(3.4)
Total Liabilities	(4.2)	(5.3)
Fair Value, Measurements, Recurring [Member] | Level One [Member]
Asset Class:
Mutual fund investments in a non-qualified savings plan	1.6	1.9
Total Assets	1.6	1.9
Liability Class:
Liabilities related to non-qualified savings plan	(1.6)	(1.9)
Derivatives – natural gas instruments	0	0
Total Liabilities	(1.6)	(1.9)
Fair Value, Measurements, Recurring [Member] | Level Two [Member]
Asset Class:
Mutual fund investments in a non-qualified savings plan	0	0
Total Assets	0	0
Liability Class:
Liabilities related to non-qualified savings plan	0	0
Derivatives – natural gas instruments	(2.6)	(3.4)
Total Liabilities	(2.6)	(3.4)
Fair Value, Measurements, Recurring [Member] | Level Three [Member]
Asset Class:
Mutual fund investments in a non-qualified savings plan	0	0
Total Assets	0	0
Liability Class:
Liabilities related to non-qualified savings plan	0	0
Derivatives – natural gas instruments	0	0
Total Liabilities	$ 0	$ 0

FAIR VALUE MEASUREMENTS (Additi

FAIR VALUE MEASUREMENTS (Additional Information) (Details) - USD ($)	Dec. 31, 2015	Dec. 31, 2014	Jun. 30, 2014
4.875% Senior Notes [Member]
Debt Instrument [Line Items]
Stated interest rate	4.875%	4.875%
Fair value of senior notes	$ 237,700,000
Aggregate principal amount due at maturity	250,000,000		$ 250,000,000
Credit Agreement [Member]
Debt Instrument [Line Items]
Aggregate principal amount due at maturity	477,000,000
Fair value of credit agreement debt	472,200,000
Fair Value, Measurements, Recurring [Member]
Debt Instrument [Line Items]
Mutual fund investments in a non-qualified savings plan	$ 1,600,000	$ 1,900,000

OPERATING SEGMENTS (Segment Inf

OPERATING SEGMENTS (Segment Information) (Details) $ in Millions	3 Months Ended									12 Months Ended
	Dec. 31, 2015USD ($)	Sep. 30, 2015USD ($)	Jun. 30, 2015USD ($)	Mar. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Sep. 30, 2014USD ($)	Jun. 30, 2014USD ($)	Mar. 31, 2014USD ($)	Dec. 31, 2013USD ($)	Dec. 31, 2015USD ($)segment	Dec. 31, 2014USD ($)facility	Dec. 31, 2013USD ($)
Segment Reporting [Abstract]
Number of reportable segments | segment										2
Segment Reporting Information [Line Items]
Sales	$ 289.3	$ 232.7	$ 183.7	$ 393	$ 433.4	$ 240.5	$ 186.6	$ 422		$ 1,098.7	$ 1,282.5	$ 1,129.6
Shipping and handling cost										261.5	337.7	301.7
Operating earnings (loss)										221.4	311	185.6
Depreciation, depletion and amortization										78.3	78	73
Total assets	1,628.9				1,637.2				$ 1,404.8	1,628.9	1,637.2	1,404.8
Capital expenditures										217.6	$ 125.2	122.7
Number of locations closed | facility											1
Gain from the settlement of an insurance claim						$ 83.3				0	$ 83.3	0
Reportable Segments [Member] | Salt [Member]
Segment Reporting Information [Line Items]
Sales										849	1,002.6	920.5
Shipping and handling cost										239.1	309.3	280.7
Operating earnings (loss)										215.2	291.4	181.3
Depreciation, depletion and amortization										43.9	44.8	45.1
Total assets	896.5				1,045.2				942.2	896.5	1,045.2	942.2
Capital expenditures										106.5	67.9	79.8
Gain from the settlement of an insurance claim											82.3
Charges incurred resulting from a court decision									4.7
Capital expenditures related to the replacement of property, plant and equipment due to tornado												15
Reportable Segments [Member] | Plant Nutrition [Member]
Segment Reporting Information [Line Items]
Sales										238.4	270.2	198.6
Shipping and handling cost										22.4	28.4	21
Operating earnings (loss)										57.9	74.8	58.7
Depreciation, depletion and amortization										29.8	27.3	23.8
Total assets	679.7				536.2				386.8	679.7	536.2	386.8
Capital expenditures										92.8	42.1	38.8
Gain from the settlement of an insurance claim									9
Corporate & Other [Member]
Segment Reporting Information [Line Items]
Sales										11.3	9.7	10.5
Shipping and handling cost										0	0	0
Operating earnings (loss)										(51.7)	(55.2)	(54.4)
Depreciation, depletion and amortization										4.6	5.9	4.1
Total assets	$ 52.7				$ 55.8				$ 75.8	52.7	55.8	75.8
Capital expenditures										18.3	15.2	4.1
Costs incurred to consolidate management records											4.2
Gain from the settlement of an insurance claim											1
Intersegment Sales [Member]
Segment Reporting Information [Line Items]
Sales										(7.8)	(8)	(8.1)
Intersegment Sales [Member] | Salt [Member]
Segment Reporting Information [Line Items]
Sales										0.1	0.9	0.9
Intersegment Sales [Member] | Plant Nutrition [Member]
Segment Reporting Information [Line Items]
Sales										$ 7.7	$ 7.1	$ 7.2

OPERATING SEGMENTS (Information

OPERATING SEGMENTS (Information by Geographic Area) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales	$ 289.3	$ 232.7	$ 183.7	$ 393	$ 433.4	$ 240.5	$ 186.6	$ 422	$ 1,098.7	$ 1,282.5	$ 1,129.6
Long-lived assets	1,115				932.6				1,115	932.6
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales									834.6	975.2	774.3
Long-lived assets	502.1				420				502.1	420
Canada [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales									198.4	260	256.7
Long-lived assets	394.3				413.7				394.3	413.7
United Kingdom [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales									56.8	41.2	87.1
Long-lived assets	95.7				92.3				95.7	92.3
Brazil [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	116.4				0				116.4	0
Other [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales									8.9	6.1	$ 11.5
Long-lived assets	$ 6.5				$ 6.6				$ 6.5	$ 6.6

EARNINGS PER SHARE (Details)

EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Numerator:
Net earnings	$ 58.4	$ 27	$ 13.2	$ 60.6	$ 80.5	$ 87.9	$ (0.7)	$ 50.2	$ 159.2	$ 217.9	$ 130.8
Less: net earnings allocated to participating securities									(1)	(1.5)	(1)
Net earnings available to common shareholders									$ 158.2	$ 216.4	$ 129.8
Denominator:
Weighted-average common shares outstanding, shares for basic earnings per share (in shares)	33,701	33,696	33,682	33,626	33,600	33,575	33,549	33,502	33,677	33,557	33,403
Weighted average equity awards outstanding									15	24	17
Shares for diluted earnings per share	33,714	33,708	33,701	33,649	33,617	33,601	33,549	33,520	33,692	33,581	33,420
Basic net earnings per common share (in dollars per share)	$ 1.72	$ 0.80	$ 0.39	$ 1.79	$ 2.38	$ 2.60	$ (0.02)	$ 1.49	$ 4.70	$ 6.45	$ 3.89
Diluted net earnings per common share (in dollars per share)	$ 1.72	$ 0.80	$ 0.39	$ 1.79	$ 2.38	$ 2.60	$ (0.02)	$ 1.49	$ 4.69	$ 6.44	$ 3.88
Net earnings allocated to participating securities (in shares)									198	227	250
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive weighted options outstanding (in shares)									432	381	455

QUARTERLY RESULTS (Unaudited)87

QUARTERLY RESULTS (Unaudited) (Schedule of Quarterly Results) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Quarterly Financial Data [Abstract]
Sales	$ 289.3	$ 232.7	$ 183.7	$ 393	$ 433.4	$ 240.5	$ 186.6	$ 422	$ 1,098.7	$ 1,282.5	$ 1,129.6
Gross profit	98.3	68	50.6	113.2	141.8	149.8	37.5	92.3	330.1	421.4	286
Net earnings	$ 58.4	$ 27	$ 13.2	$ 60.6	$ 80.5	$ 87.9	$ (0.7)	$ 50.2	$ 159.2	$ 217.9	$ 130.8
Net earnings (loss) per share, basic (in dollars per share)	$ 1.72	$ 0.80	$ 0.39	$ 1.79	$ 2.38	$ 2.60	$ (0.02)	$ 1.49	$ 4.70	$ 6.45	$ 3.89
Net earnings (loss) per share, diluted (in dollars per share)	$ 1.72	$ 0.80	$ 0.39	$ 1.79	$ 2.38	$ 2.60	$ (0.02)	$ 1.49	$ 4.69	$ 6.44	$ 3.88
Basic weighted-average shares outstanding (in shares)	33,701	33,696	33,682	33,626	33,600	33,575	33,549	33,502	33,677	33,557	33,403
Diluted weighted-average shares outstanding (in shares)	33,714	33,708	33,701	33,649	33,617	33,601	33,549	33,520	33,692	33,581	33,420

QUARTERLY RESULTS QUARTERLY RES

QUARTERLY RESULTS QUARTERLY RESULTS (Unaudited) (Schedule of Quarterly Results Additional Information) (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Sep. 30, 2014	Jun. 30, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Quarterly Financial Information Disclosure [Abstract]
Gain from the settlement of an insurance claim	$ 83.3		$ 0	$ 83.3	$ 0
Gain from the settlement of an insurance claim, net of taxes	60.6
Gain on product cost	82.3
Gain on selling, general and administrative expenses	$ 1
Cost related to refinancing		$ 6.9
Cost related to refinancing, net of tax		$ 5.1
8% Senior Notes [Member]
Debt Instrument [Line Items]
Stated interest rate			8.00%
4.875% Senior Notes [Member]
Debt Instrument [Line Items]
Stated interest rate		4.875%

SUBSEQUENT EVENT (Additional In

SUBSEQUENT EVENT (Additional Information) (Details) $ / shares in Units, $ in Millions	Feb. 04, 2016$ / shares	Feb. 19, 2016USD ($)position$ / shares	Dec. 31, 2015$ / shares	Sep. 30, 2014$ / shares	Jun. 30, 2014$ / shares	Mar. 31, 2014$ / shares	Dec. 31, 2015$ / shares	Dec. 31, 2014$ / shares	Dec. 31, 2013$ / shares
Subsequent Event [Line Items]
Cash dividends per share (in dollars per share)			$ 0.66	$ 0.66	$ 0.66	$ 0.66	$ 2.64	$ 2.40	$ 2.18
Subsequent Event [Member]
Subsequent Event [Line Items]
Dividend declaration date	Feb. 4, 2016
Cash dividend declared (in dollars per share)	$ 0.695
Percentage increase of dividends declared over dividends paid in last fiscal year (in hundredths)	5.00%
Dividend payable date	Mar. 15, 2016
Stockholders of record date	Feb. 29, 2016
Expected restructuring charge | $		$ 4
Expected restructuring costs per diluted share (in dollars per share)		$ 0.07
Expected workforce reduction | position		150

Schedule II Valuation Reserves

Schedule II Valuation Reserves (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Allowance for Doubtful Accounts [Member]
Valuation Reserves [Roll Forward]
Balance at the Beginning of the Year	$ 1.4	$ 1.6	$ 2.4
Additions (Deductions) Charged to Expense	0.6	0.3	0.7
Deductions	(0.7)	(0.5)	(1.5)
Balance at the End of the Year	1.3	1.4	1.6
Valuation Allowance of Deferred Tax Assets [Member]
Valuation Reserves [Roll Forward]
Balance at the Beginning of the Year	1	1.1	1.3
Additions (Deductions) Charged to Expense	0.1	0.2	0
Deductions	(0.2)	(0.3)	(0.2)
Balance at the End of the Year	$ 0.9	$ 1	$ 1.1