Summary of Significant Accounting Policies (Policies)	12 Months Ended
Dec. 31, 2017
Summary of Significant Accounting Policies [Abstract]
Nature of Operations	Nature of Operations – Tennant Company is a world leader in designing, manufacturing and marketing solutions that empower customers to achieve quality cleaning performance, significantly reduce environmental impact and help create a cleaner, safer, healthier world. Tennant offers products and solutions consisting of mechanized cleaning equipment, detergent-free and other sustainable cleaning technologies, aftermarket parts and consumables, equipment maintenance and repair service, specialty surface coatings, and business solutions such as financing, rental and leasing programs, and machine-to-machine asset management solutions. Tennant products are used in many types of environments including: Retail establishments, distribution centers, factories and warehouses, public venues such as arenas and stadiums, office buildings, schools and universities, hospitals and clinics, parking lots and streets, and more. Customers include contract cleaners to whom organizations outsource facilities maintenance, as well as businesses that perform facilities maintenance themselves. The Company reaches these customers through the industry's largest direct sales and service organization and through a strong and well-supported network of authorized distributors worldwide. In April 2017, the Company completed its acquisition of the IPC Group business. IPC manufactures a complete range of commercial cleaning products including mechanized cleaning equipment, wet & dry vacuum cleaners, cleaning tools & carts and high pressure washers. These products are sold into similar vertical market applications as those listed above, but also into office cleaning and hospitality vertical markets through a global direct sales and service organization and network of distributors. IPC markets products and services under the following valued brands: IPC, Gansow, Vaclensa, Portotecnica, Soteco and private-label brands.
Consolidation	Consolidation – The Consolidated Financial Statements include the accounts of Tennant Company and its subsidiaries. All intercompany transactions and balances have been eliminated. In these Notes to the Consolidated Financial Statements, Tennant Company is referred to as “Tennant,” “we,” “us,” or “our.”
Translations of Non-U.S. Currency	Translation of Non-U.S. Currency – Foreign currency-denominated assets and liabilities have been translated to U.S. dollars at year-end exchange rates, while income and expense items are translated at average exchange rates prevailing during the year. Gains or losses resulting from translation are included as a separate component of Accumulated Other Comprehensive Loss. The balance of cumulative foreign currency translation adjustments recorded within Accumulated Other Comprehensive Loss as of December 31, 2017, 2016 and 2015 was a net loss of $15,778, $44,444 and $44,585, respectively. The majority of translation adjustments are not adjusted for income taxes as substantially all translation adjustments relate to permanent investments in non-U.S. subsidiaries. Net Foreign Currency Transaction Losses are included in Other Income (Expense).
Use of Estimates	Use of Estimates – In preparing the consolidated financial statements in conformity with U.S. generally accepted accounting principles ("U.S. GAAP"), management must make decisions that impact the reported amounts of assets, liabilities, revenues, expenses and the related disclosures, including disclosures of contingent assets and liabilities. Such decisions include the selection of the appropriate accounting principles to be applied and the assumptions on which to base accounting estimates. Estimates are used in determining, among other items, sales promotions and incentives accruals, inventory valuation, warranty reserves, allowance for doubtful accounts, pension and postretirement accruals, useful lives for intangible assets, and future cash flows associated with impairment testing for Goodwill and other long-lived assets. These estimates and assumptions are based on management’s best estimates and judgments. Management evaluates its estimates and assumptions on an ongoing basis using historical experience and other factors that management believes to be reasonable under the circumstances. We adjust such estimates and assumptions when facts and circumstances dictate. A number of these factors include, among others, economic conditions, credit markets, foreign currency, commodity cost volatility and consumer spending and confidence, all of which have combined to increase the uncertainty inherent in such estimates and assumptions. As future events and their effects cannot be determined with precision, actual amounts could differ significantly from those estimated at the time the consolidated financial statements are prepared. Changes in those estimates resulting from continuing changes in the economic environment will be reflected in the financial statements in future periods.
Cash and Cash Equivalents	Cash and Cash Equivalents – We consider all highly liquid investments with maturities of three months or less from the date of purchase to be cash equivalents.
Restricted Cash	Restricted Cash – We have a total of $653 as of December 31, 2017 that serves as collateral backing certain bank guarantees and is therefore restricted. This money is invested in time deposits.
Receivables	Receivables – Credit is granted to our customers in the normal course of business. Receivables are recorded at original carrying value less reserves for estimated uncollectible accounts and sales returns. To assess the collectability of these receivables, we perform ongoing credit evaluations of our customers’ financial condition. Through these evaluations, we may become aware of a situation where a customer may not be able to meet its financial obligations due to deterioration of its financial viability, credit ratings or bankruptcy. The reserve requirements are based on the best facts available to us and are reevaluated and adjusted as additional information becomes available. Our reserves are also based on amounts determined by using percentages applied to trade receivables. These percentages are determined by a variety of factors including, but not limited to, current economic trends, historical payment and bad debt write-off experience. An account is considered past-due or delinquent when it has not been paid within the contractual terms. Uncollectible accounts are written off against the reserves when it is deemed that a customer account is uncollectible.
Inventories	Inventories – Inventories are valued at the lower of cost or net realizable value. Cost is determined on a first-in, first-out (“FIFO”) basis except for Inventories in North America, which are determined on a last-in, first-out (“LIFO”) basis.
Property, Plant and Equipment	Property, Plant and Equipment – Property, plant and equipment is carried at cost. Additions and improvements that extend the lives of the assets are capitalized while expenditures for repairs and maintenance are expensed as incurred. We generally depreciate buildings and improvements by the straight-line method over a life of 30 years. Other property, plant and equipment are generally depreciated using the straight-line method based on lives of 3 years to 15 years.
Equity Method Investments	Equity Method Investment – Investments in which we have the ability to exercise significant influence, but do not control, are accounted for under the equity method of accounting and are included in Other Assets on the Consolidated Balance Sheets. Under this method of accounting, our share of the net earnings or losses of the investee are presented as a component of Other Expense, Net on the Consolidated Statements of Operations. The detail regarding our equity method investment in i-team North America B.V., a joint venture that operates as the distributor of the i-mop in North America, are further described in Note 3.
Goodwill	Goodwill – Goodwill represents the excess of cost over the fair value of net assets of businesses acquired. We analyze Goodwill on an annual basis as of year end and when an event occurs or circumstances change that may reduce the fair value of one of our reporting units below its carrying amount. A goodwill impairment occurs if the carrying amount of a reporting unit exceeds its fair value. In assessing the recoverability of Goodwill, we use an analysis of qualitative factors to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount as a basis for determining whether it is necessary to perform the quantitative impairment test.
Intangible Assets	Intangible Assets – Intangible Assets consist of definite lived customer lists, trade names and technology. Generally, intangible assets classified as trade names are amortized on a straight-line basis and intangible assets classified as customer lists or technology are amortized using an accelerated method of amortization.
Impairment of Long-lived Assets and Assets Held for Sale	Impairment of Long-lived Assets and Assets Held for Sale – We periodically review our intangible and long-lived assets for impairment and assess whether events or circumstances indicate that the carrying amount of the assets may not be recoverable. We generally deem an asset group to be impaired if an estimate of undiscounted future operating cash flows is less than its carrying amount. If impaired, an impairment loss is recognized based on the excess of the carrying amount of the individual asset group over its fair value. Assets held for sale are measured at the lower of their carrying value or fair value less costs to sell. Upon retirement or disposition, the asset cost and related accumulated depreciation or amortization are removed from the accounts and a gain or loss is recognized based on the difference between the fair value of proceeds received and carrying value of the assets held for sale. In fiscal 2015, we adopted a plan to sell assets and liabilities of our Green Machines™ outdoor city cleaning line as a result of determining that the product line does not sufficiently complement our core business. The long-lived assets involved were tested for recoverability in 2015; accordingly, a pre-tax impairment loss of $11,199 was recognized, which represents the amount by which the carrying values of the assets exceeded their fair value less costs to sell. The impairment charge is included in the caption "Impairment of Long-Lived Assets" in the accompanying Consolidated Statements of Operations.
Purchase of Common Stock	Purchase of Common Stock – We repurchase our Common Stock under 2016 and 2015 repurchase programs authorized by our Board of Directors. These programs allow us to repurchase up to an aggregate of 1,393,965 shares of our Common Stock. Upon repurchase, the par value is charged to Common Stock and the remaining purchase price is charged to Additional Paid-in Capital. If the amount of the remaining purchase price causes the Additional Paid-in Capital account to be in a debit position, this amount is then reclassified to Retained Earnings. Common Stock repurchased is included in shares authorized but is not included in shares outstanding.
Warranty	Warranty – We record a liability for estimated warranty claims at the time of sale. The amount of the liability is based on the trend in the historical ratio of claims to sales, the historical length of time between the sale and resulting warranty claim, new product introductions and other factors. In the event we determine that our current or future product repair and replacement costs exceed our estimates, an adjustment to these reserves would be charged to earnings in the period such determination is made. Warranty terms on machines range from one to four years. However, the majority of our claims are paid out within the first six to nine months following a sale. The majority of the liability for estimated warranty claims represents amounts to be paid out in the near term for qualified warranty issues, with immaterial amounts reserved to be paid out for older equipment warranty issues.
Debt	Debt Issuance Costs – We record all applicable debt issuance costs related to a recognized debt liability in the Consolidated Balance Sheets as a direct deduction from the carrying amount of the debt liability, if not a line-of-credit arrangement. All debt issuance costs related to line-of-credit arrangements are recorded as part of Other Assets in the Consolidated Balance Sheets and subsequently amortized over the term of the line-of-credit arrangement. We amortize our debt issuance costs using the effective interest method over the term of the debt instrument or line-of-credit arrangement. Amortization of these costs is included as part of Interest Expense in the Consolidated Statements of Operations.
Environmental	Environmental – We record a liability for environmental clean-up on an undiscounted basis when a loss is probable and can be reasonably estimated.
Pension and Profit Sharing Plans	Pension and Profit Sharing Plans – Substantially all U.S. employees are covered by various retirement benefit plans, including postretirement medical plans and defined contribution savings plans. Pension plan costs are accrued based on actuarial estimates with the required pension cost funded annually, as needed. No new participants have entered the defined benefit pension plan since 2000.
Postretirement Benefits	Postretirement Benefits – We accrue and recognize the cost of retiree health benefits over the employees’ period of service based on actuarial estimates. Benefits are only available for U.S. employees hired before January 1, 1999.
Derivative Financial Instruments	Derivative Financial Instruments – In countries outside the U.S., we transact business in U.S. dollars and in various other currencies. We hedge our net recognized foreign currency denominated assets and liabilities with foreign exchange forward contracts to reduce the risk that the value of these assets and liabilities will be adversely affected by changes in exchange rates. We may also use foreign exchange option contracts or forward contracts to hedge certain cash flow exposures resulting from changes in foreign currency exchange rates. We enter into these foreign exchange contracts to hedge a portion of our forecasted currency denominated revenue in the normal course of business, and accordingly, they are not speculative in nature. We account for our foreign currency hedging instruments as either assets or liabilities on the balance sheet and measure them at fair value. Gains and losses resulting from changes in fair value are accounted for depending on the use of the derivative and whether it is designated and qualifies for hedge accounting. Gains and losses from foreign exchange forward contracts that hedge certain balance sheet positions are recorded each period to Net Foreign Currency Transaction Losses in our Consolidated Statements of Operations. Foreign exchange option contracts or forward contracts hedging forecasted foreign currency revenue are designated as cash flow hedges under accounting for derivative instruments and hedging activities, with gains and losses recorded each period to Accumulated Other Comprehensive Loss in our Consolidated Balance Sheets, until the forecasted transaction occurs. When the forecasted transaction occurs, we reclassify the related gain or loss on the cash flow hedge to Net Sales. In the event the underlying forecasted transaction does not occur, or it becomes probable that it will not occur, we reclassify the gain or loss on the related cash flow hedge from Accumulated Other Comprehensive Loss to Net Foreign Currency Transaction Losses in our Consolidated Statements of Operations at that time. If we do not elect hedge accounting, or the contract does not qualify for hedge accounting treatment, the changes in fair value from period to period are recorded in Net Foreign Currency Transaction Losses in our Consolidated Statements of Operations. See Note 11 for additional information regarding our hedging activities.
Revenue Recognition	Revenue Recognition – We recognize revenue when persuasive evidence of an arrangement exists, title and risk of ownership have passed to the customer, the sales price is fixed or determinable and collectability is reasonably assured. Generally, these criteria are met at the time the product is shipped. Provisions for estimated returns, rebates and discounts are provided for at the time the related revenue is recognized. Freight revenue billed to customers is included in Net Sales and the related shipping expense is included in Cost of Sales. Service revenue is recognized in the period the service is performed or ratably over the period of the related service contract. Customers may obtain financing through third-party leasing companies to assist in their acquisition of our equipment products. Certain lease transactions classified as operating leases contain retained ownership provisions or guarantees, which results in recognition of revenue over the lease term. As a result, we defer the sale of these transactions and record the sales proceeds as collateralized borrowings or deferred revenue. The underlying equipment relating to operating leases is depreciated on a straight-line basis, not to exceed the equipment’s estimated useful life. Revenues from contracts with multiple element arrangements are recognized as each element is earned. We offer service contracts in conjunction with equipment sales in addition to selling equipment and service contracts separately. Sales proceeds related to service contracts are deferred if the proceeds are received in advance of the service and recognized ratably over the contract period.
Share-based Compensation	Share-based Compensation – We account for employee share-based compensation using the fair value based method. Our share-based compensation plans are more fully described in Note 17 of the Consolidated Financial Statements.
Research and Development	Research and Development – Research and development costs are expensed as incurred.
Advertising Costs	Advertising Costs – We advertise products, technologies and solutions to customers and prospective customers through a variety of marketing campaign and promotional efforts. These efforts include tradeshows, online advertising, e-mail marketing, mailings, sponsorships and telemarketing. Advertising costs are expensed as incurred. In 2017, 2016 and 2015 such activities amounted to $8,228, $7,269 and $7,418, respectively.
Income Taxes	Income Taxes – Deferred tax assets and liabilities are recognized for the expected future tax consequences of temporary differences between the book and tax bases of existing assets and liabilities. A valuation allowance is provided when, in management’s judgment, it is more likely than not that some portion or all of the deferred tax asset will not be realized. We have established contingent tax liabilities using management’s best judgment. We follow guidance provided by Accounting Standards Codification ("ASC") 740, Income Taxes, regarding uncertainty in income taxes, to record these contingent tax liabilities (refer to Note 16 of the Consolidated Financial Statements for additional information). We adjust these liabilities as facts and circumstances change. Interest Expense is recognized in the first period the interest would begin accruing. Penalties are recognized in the period we claim or expect to claim the position in our tax return. Interest and penalties expenses are classified as an income tax expense.
Sales Tax	Sales Tax – Sales taxes collected from customers and remitted to governmental authorities are presented on a net basis.
Earnings per Share	Earnings per Share – Basic (loss) earnings per share is computed by dividing Net (Loss) Earnings Attributable to Tennant Company by the Weighted Average Shares Outstanding during the period. Diluted earnings per share assumes conversion of potentially dilutive stock options, performance shares, restricted shares and restricted stock units. These conversions are not included in our computation of diluted earnings per share if we have a net loss attributable to Tennant Company in a reporting period, as the effects are anti-dilutive.
New Accounting Pronouncements	New Accounting Pronouncements – In accordance with ASU No. 2016-09, Compensation–Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting, all excess tax benefits and tax deficiencies are recorded as a component of the provision for income taxes in the reporting period in which they occur. Additionally, we present excess tax benefits along with other income tax cash flows on the Consolidated Statements of Cash Flows as an operating activity rather than, as previously required, a financing activity. For further details regarding the implementation of this ASU and the impact on our financial statements, see Note 2.

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2017

Summary of Significant Accounting Policies [Abstract]

Nature of Operations – Tennant Company is a world leader in designing, manufacturing and marketing solutions that empower customers to achieve quality cleaning performance, significantly reduce environmental impact and help create a cleaner, safer, healthier world. Tennant offers products and solutions consisting of mechanized cleaning equipment, detergent-free and other sustainable cleaning technologies, aftermarket parts and consumables, equipment maintenance and repair service, specialty surface coatings, and business solutions such as financing, rental and leasing programs, and machine-to-machine asset management solutions. Tennant products are used in many types of environments including: Retail establishments, distribution centers, factories and warehouses, public venues such as arenas and stadiums, office buildings, schools and universities, hospitals and clinics, parking lots and streets, and more. Customers include contract cleaners to whom organizations outsource facilities maintenance, as well as businesses that perform facilities maintenance themselves. The Company reaches these customers through the industry's largest direct sales and service organization and through a strong and well-supported network of authorized distributors worldwide.

In April 2017, the Company completed its acquisition of the IPC Group business. IPC manufactures a complete range of commercial cleaning products including mechanized cleaning equipment, wet & dry vacuum cleaners, cleaning tools & carts and high pressure washers. These products are sold into similar vertical market applications as those listed above, but also into office cleaning and hospitality vertical markets through a global direct sales and service organization and network of distributors. IPC markets products and services under the following valued brands: IPC, Gansow, Vaclensa, Portotecnica, Soteco and private-label brands.

Consolidation

Consolidation – The Consolidated Financial Statements include the accounts of Tennant Company and its subsidiaries. All intercompany transactions and balances have been eliminated. In these Notes to the Consolidated Financial Statements, Tennant Company is referred to as “Tennant,” “we,” “us,” or “our.”

Translations of Non-U.S. Currency

Translation of Non-U.S. Currency – Foreign currency-denominated assets and liabilities have been translated to U.S. dollars at year-end exchange rates, while income and expense items are translated at average exchange rates prevailing during the year. Gains or losses resulting from translation are included as a separate component of Accumulated Other Comprehensive Loss. The balance of cumulative foreign currency translation adjustments recorded within Accumulated Other Comprehensive Loss as of December 31, 2017, 2016 and 2015 was a net loss of $15,778, $44,444 and $44,585, respectively. The majority of translation adjustments are not adjusted for income taxes as substantially all translation adjustments relate to permanent investments in non-U.S. subsidiaries. Net Foreign Currency Transaction Losses are included in Other Income (Expense).

Use of Estimates

Use of Estimates – In preparing the consolidated financial statements in conformity with U.S. generally accepted accounting principles ("U.S. GAAP"), management must make decisions that impact the reported amounts of assets, liabilities, revenues, expenses and the related disclosures, including disclosures of contingent assets and liabilities. Such decisions include the selection of the appropriate accounting principles to be applied and the assumptions on which to base accounting estimates. Estimates are used in determining, among other items, sales promotions and incentives accruals, inventory valuation, warranty reserves, allowance for doubtful accounts, pension and postretirement accruals, useful lives for intangible assets, and future cash flows associated with impairment testing for Goodwill and other long-lived assets. These estimates and assumptions are based on management’s best estimates and judgments. Management evaluates its estimates and assumptions on an ongoing basis using historical experience and other factors that management believes to be reasonable under the circumstances. We adjust such estimates and assumptions when facts and circumstances dictate. A number of these factors include, among others, economic conditions, credit markets, foreign currency, commodity cost volatility and consumer spending and confidence, all of which have combined to increase the uncertainty inherent in such estimates and assumptions. As future events and their effects cannot be determined with precision, actual amounts could differ significantly from those estimated at the time the consolidated financial statements are prepared. Changes in those estimates resulting from continuing changes in the economic environment will be reflected in the financial statements in future periods.

Cash and Cash Equivalents

Cash and Cash Equivalents – We consider all highly liquid investments with maturities of three months or less from the date of purchase to be cash equivalents.

Restricted Cash

Restricted Cash – We have a total of $653 as of December 31, 2017 that serves as collateral backing certain bank guarantees and is therefore restricted. This money is invested in time deposits.

Receivables

Receivables – Credit is granted to our customers in the normal course of business. Receivables are recorded at original carrying value less reserves for estimated uncollectible accounts and sales returns. To assess the collectability of these receivables, we perform ongoing credit evaluations of our customers’ financial condition. Through these evaluations, we may become aware of a situation where a customer may not be able to meet its financial obligations due to deterioration of its financial viability, credit ratings or bankruptcy. The reserve requirements are based on the best facts available to us and are reevaluated and adjusted as additional information becomes available. Our reserves are also based on amounts determined by using percentages applied to trade receivables. These percentages are determined by a variety of factors including, but not limited to, current economic trends, historical payment and bad debt write-off experience. An account is considered past-due or delinquent when it has not been paid within the contractual terms. Uncollectible accounts are written off against the reserves when it is deemed that a customer account is uncollectible.

Inventories

Inventories – Inventories are valued at the lower of cost or net realizable value. Cost is determined on a first-in, first-out (“FIFO”) basis except for Inventories in North America, which are determined on a last-in, first-out (“LIFO”) basis.

Property, Plant and Equipment

Property, Plant and Equipment – Property, plant and equipment is carried at cost. Additions and improvements that extend the lives of the assets are capitalized while expenditures for repairs and maintenance are expensed as incurred. We generally depreciate buildings and improvements by the straight-line method over a life of 30 years. Other property, plant and equipment are generally depreciated using the straight-line method based on lives of 3 years to 15 years.

Equity Method Investments

Equity Method Investment – Investments in which we have the ability to exercise significant influence, but do not control, are accounted for under the equity method of accounting and are included in Other Assets on the Consolidated Balance Sheets. Under this method of accounting, our share of the net earnings or losses of the investee are presented as a component of Other Expense, Net on the Consolidated Statements of Operations. The detail regarding our equity method investment in i-team North America B.V., a joint venture that operates as the distributor of the i-mop in North America, are further described in Note 3.

Goodwill

Goodwill – Goodwill represents the excess of cost over the fair value of net assets of businesses acquired. We analyze Goodwill on an annual basis as of year end and when an event occurs or circumstances change that may reduce the fair value of one of our reporting units below its carrying amount. A goodwill impairment occurs if the carrying amount of a reporting unit exceeds its fair value. In assessing the recoverability of Goodwill, we use an analysis of qualitative factors to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount as a basis for determining whether it is necessary to perform the quantitative impairment test.

Intangible Assets

Intangible Assets – Intangible Assets consist of definite lived customer lists, trade names and technology. Generally, intangible assets classified as trade names are amortized on a straight-line basis and intangible assets classified as customer lists or technology are amortized using an accelerated method of amortization.

Impairment of Long-lived Assets and Assets Held for Sale

Impairment of Long-lived Assets and Assets Held for Sale – We periodically review our intangible and long-lived assets for impairment and assess whether events or circumstances indicate that the carrying amount of the assets may not be recoverable. We generally deem an asset group to be impaired if an estimate of undiscounted future operating cash flows is less than its carrying amount. If impaired, an impairment loss is recognized based on the excess of the carrying amount of the individual asset group over its fair value.

Assets held for sale are measured at the lower of their carrying value or fair value less costs to sell. Upon retirement or disposition, the asset cost and related accumulated depreciation or amortization are removed from the accounts and a gain or loss is recognized based on the difference between the fair value of proceeds received and carrying value of the assets held for sale. In fiscal 2015, we adopted a plan to sell assets and liabilities of our Green Machines™ outdoor city cleaning line as a result of determining that the product line does not sufficiently complement our core business. The long-lived assets involved were tested for recoverability in 2015; accordingly, a pre-tax impairment loss of $11,199 was recognized, which represents the amount by which the carrying values of the assets exceeded their fair value less costs to sell. The impairment charge is included in the caption "Impairment of Long-Lived Assets" in the accompanying Consolidated Statements of Operations.

Purchase of Common Stock

Purchase of Common Stock – We repurchase our Common Stock under 2016 and 2015 repurchase programs authorized by our Board of Directors. These programs allow us to repurchase up to an aggregate of 1,393,965 shares of our Common Stock. Upon repurchase, the par value is charged to Common Stock and the remaining purchase price is charged to Additional Paid-in Capital. If the amount of the remaining purchase price causes the Additional Paid-in Capital account to be in a debit position, this amount is then reclassified to Retained Earnings. Common Stock repurchased is included in shares authorized but is not included in shares outstanding.

Warranty

Warranty – We record a liability for estimated warranty claims at the time of sale. The amount of the liability is based on the trend in the historical ratio of claims to sales, the historical length of time between the sale and resulting warranty claim, new product introductions and other factors. In the event we determine that our current or future product repair and replacement costs exceed our estimates, an adjustment to these reserves would be charged to earnings in the period such determination is made. Warranty terms on machines range from one to four years. However, the majority of our claims are paid out within the first six to nine months following a sale. The majority of the liability for estimated warranty claims represents amounts to be paid out in the near term for qualified warranty issues, with immaterial amounts reserved to be paid out for older equipment warranty issues.

Debt

Debt Issuance Costs – We record all applicable debt issuance costs related to a recognized debt liability in the Consolidated Balance Sheets as a direct deduction from the carrying amount of the debt liability, if not a line-of-credit arrangement. All debt issuance costs related to line-of-credit arrangements are recorded as part of Other Assets in the Consolidated Balance Sheets and subsequently amortized over the term of the line-of-credit arrangement. We amortize our debt issuance costs using the effective interest method over the term of the debt instrument or line-of-credit arrangement. Amortization of these costs is included as part of Interest Expense in the Consolidated Statements of Operations.

Environmental

Environmental – We record a liability for environmental clean-up on an undiscounted basis when a loss is probable and can be reasonably estimated.

Pension and Profit Sharing Plans

Pension and Profit Sharing Plans – Substantially all U.S. employees are covered by various retirement benefit plans, including postretirement medical plans and defined contribution savings plans. Pension plan costs are accrued based on actuarial estimates with the required pension cost funded annually, as needed. No new participants have entered the defined benefit pension plan since 2000.

Postretirement Benefits

Postretirement Benefits – We accrue and recognize the cost of retiree health benefits over the employees’ period of service based on actuarial estimates. Benefits are only available for U.S. employees hired before January 1, 1999.

Derivative Financial Instruments

Derivative Financial Instruments – In countries outside the U.S., we transact business in U.S. dollars and in various other currencies. We hedge our net recognized foreign currency denominated assets and liabilities with foreign exchange forward contracts to reduce the risk that the value of these assets and liabilities will be adversely affected by changes in exchange rates. We may also use foreign exchange option contracts or forward contracts to hedge certain cash flow exposures resulting from changes in foreign currency exchange rates. We enter into these foreign exchange contracts to hedge a portion of our forecasted currency denominated revenue in the normal course of business, and accordingly, they are not speculative in nature.

We account for our foreign currency hedging instruments as either assets or liabilities on the balance sheet and measure them at fair value. Gains and losses resulting from changes in fair value are accounted for depending on the use of the derivative and whether it is designated and qualifies for hedge accounting. Gains and losses from foreign exchange forward contracts that hedge certain balance sheet positions are recorded each period to Net Foreign Currency Transaction Losses in our Consolidated Statements of Operations. Foreign exchange option contracts or forward contracts hedging forecasted foreign currency revenue are designated as cash flow hedges under accounting for derivative instruments and hedging activities, with gains and losses recorded each period to Accumulated Other Comprehensive Loss in our Consolidated Balance Sheets, until the forecasted transaction occurs. When the forecasted transaction occurs, we reclassify the related gain or loss on the cash flow hedge to Net Sales. In the event the underlying forecasted transaction does not occur, or it becomes probable that it will not occur, we reclassify the gain or loss on the related cash flow hedge from Accumulated Other Comprehensive Loss to Net Foreign Currency Transaction Losses in our Consolidated Statements of Operations at that time. If we do not elect hedge accounting, or the contract does not qualify for hedge accounting treatment, the changes in fair value from period to period are recorded in Net Foreign Currency Transaction Losses in our Consolidated Statements of Operations. See Note 11 for additional information regarding our hedging activities.

Revenue Recognition

Revenue Recognition – We recognize revenue when persuasive evidence of an arrangement exists, title and risk of ownership have passed to the customer, the sales price is fixed or determinable and collectability is reasonably assured. Generally, these criteria are met at the time the product is shipped. Provisions for estimated returns, rebates and discounts are provided for at the time the related revenue is recognized. Freight revenue billed to customers is included in Net Sales and the related shipping expense is included in Cost of Sales. Service revenue is recognized in the period the service is performed or ratably over the period of the related service contract.

Customers may obtain financing through third-party leasing companies to assist in their acquisition of our equipment products. Certain lease transactions classified as operating leases contain retained ownership provisions or guarantees, which results in recognition of revenue over the lease term. As a result, we defer the sale of these transactions and record the sales proceeds as collateralized borrowings or deferred revenue. The underlying equipment relating to operating leases is depreciated on a straight-line basis, not to exceed the equipment’s estimated useful life.

Revenues from contracts with multiple element arrangements are recognized as each element is earned. We offer service contracts in conjunction with equipment sales in addition to selling equipment and service contracts separately. Sales proceeds related to service contracts are deferred if the proceeds are received in advance of the service and recognized ratably over the contract period.

Share-based Compensation

Share-based Compensation – We account for employee share-based compensation using the fair value based method. Our share-based compensation plans are more fully described in Note 17 of the Consolidated Financial Statements.

Research and Development

Research and Development – Research and development costs are expensed as incurred.

Advertising Costs

Advertising Costs – We advertise products, technologies and solutions to customers and prospective customers through a variety of marketing campaign and promotional efforts. These efforts include tradeshows, online advertising, e-mail marketing, mailings, sponsorships and telemarketing. Advertising costs are expensed as incurred. In 2017, 2016 and 2015 such activities amounted to $8,228, $7,269 and $7,418, respectively.

Income Taxes

Income Taxes – Deferred tax assets and liabilities are recognized for the expected future tax consequences of temporary differences between the book and tax bases of existing assets and liabilities. A valuation allowance is provided when, in management’s judgment, it is more likely than not that some portion or all of the deferred tax asset will not be realized. We have established contingent tax liabilities using management’s best judgment. We follow guidance provided by Accounting Standards Codification ("ASC") 740, Income Taxes, regarding uncertainty in income taxes, to record these contingent tax liabilities (refer to Note 16 of the Consolidated Financial Statements for additional information). We adjust these liabilities as facts and circumstances change. Interest Expense is recognized in the first period the interest would begin accruing. Penalties are recognized in the period we claim or expect to claim the position in our tax return. Interest and penalties expenses are classified as an income tax expense.

Sales Tax

Sales Tax – Sales taxes collected from customers and remitted to governmental authorities are presented on a net basis.

Earnings per Share

Earnings per Share – Basic (loss) earnings per share is computed by dividing Net (Loss) Earnings Attributable to Tennant Company by the Weighted Average Shares Outstanding during the period. Diluted earnings per share assumes conversion of potentially dilutive stock options, performance shares, restricted shares and restricted stock units. These conversions are not included in our computation of diluted earnings per share if we have a net loss attributable to Tennant Company in a reporting period, as the effects are anti-dilutive.

New Accounting Pronouncements

New Accounting Pronouncements – In accordance with ASU No. 2016-09, Compensation–Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting, all excess tax benefits and tax deficiencies are recorded as a component of the provision for income taxes in the reporting period in which they occur. Additionally, we present excess tax benefits along with other income tax cash flows on the Consolidated Statements of Cash Flows as an operating activity rather than, as previously required, a financing activity. For further details regarding the implementation of this ASU and the impact on our financial statements, see Note 2.