Basis of Financial Statement Presentation	3 Months Ended
Mar. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Financial Statement Presentation	Basis of Financial Statement Presentation General The accompanying unaudited interim condensed consolidated financial statements of Alamo Group Inc. and its subsidiaries (the “Company”) have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulations S-X. Accordingly, they do not include all of the information and footnotes required by U.S. GAAP for complete financial statements. In the opinion of management, all adjustments (consisting of normal recurring accruals) considered necessary for a fair presentation have been included. Operating results for the periods presented are not necessarily indicative of the results that may be expected for the year ending December 31, 2018. The balance sheet at December 31, 2017 has been derived from the audited financial statements at that date but does not include all of the information and footnotes required by U.S. GAAP for complete financial statements. For further information, refer to the consolidated financial statements and footnotes thereto included in the Company’s annual report on Form 10-K for the year ended December 31, 2017 (the "2017 10-K"). Reclassifications Certain amounts reported for the three months ended March 31, 2017 have been reclassified in order to conform to the 2018 presentation. Accounting Pronouncements Adopted on January 1, 2018 In May 2014, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2014-09, “Revenue from Contracts with Customers (Topic 606),” which supersedes the revenue recognition requirements in Accounting Standards Codification ("ASC") Topic 605. “Revenue Recognition,” and most industry-specific guidance. Effective January 1, 2018 the Company adopted the provisions of Topic 606 using the modified retrospective method of adoption. There was no impact to our financial position or results of operations as of and for the three months ended March 31, 2018 as a result of adopting Topic 606. Therefore, there was no cumulative-effect adjustment to retained earnings as of January 1, 2018 for the impact of the adoption of Topic 606. See “Revenue Recognition” below for our accounting policy affected by our adoption of Topic 606. In March 2017, the FASB issued ASU No. 2017-07, “Compensation-Retirement Benefits (Topic 715),” which requires employers to report the service cost component of net periodic pension cost and net periodic postretirement benefit cost in the same line item as other compensation costs arising from services rendered by the pertinent employees during the period. It also requires the other components of net periodic pension cost and net periodic postretirement benefit cost (non-service cost components) to be presented in the income statement separately from the service cost component and outside a subtotal of income from operations. This ASU is to be applied retrospectively for income statement items and prospectively for any capitalized benefit costs. The adoption of this ASU effective January 1, 2018 did not affect our financial position or results of operations. Accordingly, for the three months ended March 31, 2018 and 2017, we reclassified the non-service cost components out of selling, general and administrative expenses of $62,000 and $150,000, respectively, and into other income (expense), net. In March 2018, the FASB issued ASU No. 2018-05, “Income Taxes (Topic 740)-Amendments to SEC Paragraphs Pursuant to SEC Staff Accounting Bulletin No. 118,” which amends certain SEC material in Topic 740 for the income tax accounting implications of the recently issued Tax Reform. This guidance clarifies the application of Topic 740 in situations where a registrant does not have the necessary information available, prepared, or analyzed in reasonable detail to complete the accounting under ASC Topic 740 for certain income tax effects of Tax Reform for the reporting period in which the Tax Reform was enacted. We are currently evaluating the effects of Tax Reform, and in the absence of clarifying guidance in the application of certain provisions of Tax Reform, we used reasonable estimates to determine our provisional tax amounts and are awaiting guidance for those items for which a reasonable estimate cannot be made. Accounting Pronouncements Not Yet Adopted In February 2016, the FASB issued ASU No. 2016-02, “Leases.” This update requires that a lessee recognize in the statement of financial position a liability to make lease payments and a right-of-use asset representing its right to use the underlying asset for the lease term. For leases with a term of 12 months or less, a lessee is permitted to make an accounting policy election by class of underlying asset not to recognize lease assets and lease liabilities. Similar to current guidance, the update continues to differentiate between finance leases and operating leases, however this distinction now primarily relates to differences in the manner of expense recognition over time and in the classification of lease payments in the statement of cash flows. The updated guidance leaves the accounting for leases by lessors largely unchanged from existing GAAP. Entities are required to use a modified retrospective adoption, with certain relief provisions, for leases that exist or are entered into after the beginning of the earliest comparative period in the financial statements when adopted. The guidance will become effective for us on January 1, 2019. The impacts that adoption of the ASU is expected to have on our consolidated financial statements and related disclosures are being evaluated. Additionally, we have not yet determined the effect of the ASU on our internal control over financial reporting or other changes in business practices and processes. In February 2018, the FASB issued ASU 2018-02, “Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income,” to allow reclassification from accumulated other comprehensive income to retained earnings for stranded tax effects resulting from the Tax Cuts and Jobs Act ("TCJA"). Upon adoption of the ASU, entities will be required to disclose a description of the accounting policy for releasing income tax effects from accumulated other comprehensive income. The standard is required to be adopted for periods beginning after December 15, 2018, with early adoption available for any set of financial statements that have yet to be issued or made available for issuance including retrospectively for any period in which the effect of the change is the U.S. corporate income tax rate in the TCJA is recognized.

Basis of Financial Statement Presentation

General

The accompanying unaudited interim condensed consolidated financial statements of Alamo Group Inc. and its subsidiaries (the “Company”) have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulations S-X. Accordingly, they do not include all of the information and footnotes required by U.S. GAAP for complete financial statements. In the opinion of management, all adjustments (consisting of normal recurring accruals) considered necessary for a fair presentation have been included. Operating results for the periods presented are not necessarily indicative of the results that may be expected for the year ending December 31, 2018. The balance sheet at December 31, 2017 has been derived from the audited financial statements at that date but does not include all of the information and footnotes required by U.S. GAAP for complete financial statements. For further information, refer to the consolidated financial statements and footnotes thereto included in the Company’s annual report on Form 10-K for the year ended December 31, 2017 (the "2017 10-K").

Reclassifications

Certain amounts reported for the three months ended March 31, 2017 have been reclassified in order to conform to the 2018 presentation.

Accounting Pronouncements Adopted on January 1, 2018

In May 2014, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2014-09, “Revenue from Contracts with Customers (Topic 606),” which supersedes the revenue recognition requirements in Accounting Standards Codification ("ASC") Topic 605. “Revenue Recognition,” and most industry-specific guidance. Effective January 1, 2018 the Company adopted the provisions of Topic 606 using the modified retrospective method of adoption. There was no impact to our financial position or results of operations as of and for the three months ended March 31, 2018 as a result of adopting Topic 606. Therefore, there was no cumulative-effect adjustment to retained earnings as of January 1, 2018 for the impact of the adoption of Topic 606. See “Revenue Recognition” below for our accounting policy affected by our adoption of Topic 606.

In March 2017, the FASB issued ASU No. 2017-07, “Compensation-Retirement Benefits (Topic 715),” which requires employers to report the service cost component of net periodic pension cost and net periodic postretirement benefit cost in the same line item as other compensation costs arising from services rendered by the pertinent employees during the period. It also requires the other components of net periodic pension cost and net periodic postretirement benefit cost (non-service cost components) to be presented in the income statement separately from the service cost component and outside a subtotal of income from operations. This ASU is to be applied retrospectively for income statement items and prospectively for any capitalized benefit costs. The adoption of this ASU effective January 1, 2018 did not affect our financial position or results of operations. Accordingly, for the three months ended March 31, 2018 and 2017, we reclassified the non-service cost components out of selling, general and administrative expenses of $62,000 and $150,000, respectively, and into other income (expense), net.

In March 2018, the FASB issued ASU No. 2018-05, “Income Taxes (Topic 740)-Amendments to SEC Paragraphs Pursuant to SEC Staff Accounting Bulletin No. 118,” which amends certain SEC material in Topic 740 for the income tax accounting implications of the recently issued Tax Reform. This guidance clarifies the application of Topic 740 in situations where a registrant does not have the necessary information available, prepared, or analyzed in reasonable detail to complete the accounting under ASC Topic 740 for certain income tax effects of Tax Reform for the reporting period in which the Tax Reform was enacted. We are currently evaluating the effects of Tax Reform, and in the absence of clarifying guidance in the application of certain provisions of Tax Reform, we used reasonable estimates to determine our provisional tax amounts and are awaiting guidance for those items for which a reasonable estimate cannot be made.

Accounting Pronouncements Not Yet Adopted

In February 2016, the FASB issued ASU No. 2016-02, “Leases.” This update requires that a lessee recognize in the statement of financial position a liability to make lease payments and a right-of-use asset representing its right to use the underlying asset for the lease term. For leases with a term of 12 months or less, a lessee is permitted to make an accounting policy election by class of underlying asset not to recognize lease assets and lease liabilities. Similar to current guidance, the update continues to differentiate between finance leases and operating leases, however this distinction now primarily relates to differences in the manner of expense recognition over time and in the classification of lease payments in the statement of cash flows. The updated guidance leaves the accounting for leases by lessors largely unchanged from existing GAAP. Entities are required to use a modified retrospective adoption, with certain relief provisions, for leases that exist or are entered into after the beginning of the earliest comparative period in the financial statements when adopted. The guidance will become effective for us on January 1, 2019. The impacts that adoption of the ASU is expected to have on our consolidated financial statements and related disclosures are being evaluated. Additionally, we have not yet determined the effect of the ASU on our internal control over financial reporting or other changes in business practices and processes.

In February 2018, the FASB issued ASU 2018-02, “Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income,” to allow reclassification from accumulated other comprehensive income to retained earnings for stranded tax effects resulting from the Tax Cuts and Jobs Act ("TCJA"). Upon adoption of the ASU, entities will be required to disclose a description of the accounting policy for releasing income tax effects from accumulated other comprehensive income. The standard is required to be adopted for periods beginning after December 15, 2018, with early adoption available for any set of financial statements that have yet to be issued or made available for issuance including retrospectively for any period in which the effect of the change is the U.S. corporate income tax rate in the TCJA is recognized.