Basis of presentation (Policies)	6 Months Ended
Basis of presentation (Policies)	Jun. 30, 2020
Accounting Policies [Abstract]
Use of Estimates	We have made a number of estimates and assumptions relating to the reporting of assets and liabilities and the disclosure of contingent assets and liabilities to prepare these condensed consolidated financial statements. Actual results could differ materially from these estimates. The most significant estimates are related to goodwill and other long-lived assets, pension and other retirement benefit obligations, legal contingencies, allowance for doubtful accounts, deferred tax assets, purchase price allocations and foreign currency translation.
Consolidation	Consolidation The condensed consolidated financial statements include our controlled subsidiaries. Control is determined based on ownership rights or, when applicable, based on whether we are considered to be the primary beneficiary of a variable interest entity. See "Venezuela" section below for further information. For controlled subsidiaries that are not wholly-owned, the noncontrolling interests are included in net income and in total equity. Investments in businesses that we do not control, but for which we have the ability to exercise significant influence over operating and financial policies, are accounted for under the equity method and our proportionate share of income or loss is recorded in other operating income (expense). Investments in businesses for which we do not have the ability to exercise significant influence over operating and financial policies are accounted for at fair value, if readily determinable, with changes in fair value recognized in net income. For equity investments that do not have a readily determinable fair value, we measure these investments at cost minus impairment, if any, plus or minus changes from observable price changes. All intercompany accounts and transactions have been eliminated in consolidation.
Foreign Currency Translation	Foreign Currency Translation Our condensed consolidated financial statements are reported in U.S. dollars. Our foreign subsidiaries maintain their records primarily in the currency of the country in which they operate. The method of translating local currency financial information into U.S. dollars depends on whether the economy in which our foreign subsidiary operates has been designated as highly inflationary or not. Economies with a three-year cumulative inflation rate of more than 100% are considered highly inflationary. Assets and liabilities of foreign subsidiaries in non-highly inflationary economies are translated into U.S. dollars using rates of exchange at the balance sheet date. Translation adjustments are recorded in other comprehensive income (loss). Revenues and expenses are translated at rates of exchange in effect during the year. Transaction gains and losses are recorded in net income. Foreign subsidiaries that operate in highly inflationary countries use the U.S. dollar as their functional currency. Local currency monetary assets and liabilities are remeasured into U.S. dollars using rates of exchange as of each balance sheet date, with remeasurement adjustments and other transaction gains and losses recognized in earnings. Other than nonmonetary equity securities, nonmonetary assets and liabilities do not fluctuate with changes in local currency exchange rates to the dollar. For nonmonetary equity securities traded in highly inflationary economies, the fair market value of the equity securities are remeasured at the current exchange rates to determine gain or loss to be recorded in net income. Revenues and expenses are translated at rates of exchange in effect during the year. Argentina We operate in Argentina through wholly owned subsidiaries and a smaller controlled subsidiary (together "Brink's Argentina"). Revenues from Brink's Argentina represented approximately 5% of our consolidated revenues for the first six months of 2020 and 6% of our consolidated revenues for the first six months of 2019. The operating environment in Argentina continues to present business challenges, including ongoing devaluation of the Argentine peso and significant inflation. In the first six months of 2020 and 2019, the Argentine peso declined approximately 15% (from 59.9 to 70.4 pesos to the U.S. dollar) and approximately 12% (from 37.6 to 42.6 pesos to the U.S. dollar), respectively. For the year ended December 31, 2019, the Argentine peso declined approximately 37% (from 37.6 to 59.9 pesos to the U.S. dollar). Beginning July 1, 2018, we designated Argentina's economy as highly inflationary for accounting purposes. As a result, we consolidated Brink's Argentina using our accounting policy for subsidiaries operating in highly inflationary economies beginning with the third quarter of 2018. Argentine peso-denominated monetary assets and liabilities are remeasured at each balance sheet date using the currency exchange rate then in effect, with currency remeasurement gains and losses recognized in earnings. In the first six months of 2020, we recognized a $3.5 million pretax remeasurement loss. In the first six months of 2019, we recognized a $3.4 million pretax remeasurement loss. At June 30, 2020, Argentina's economy remains highly inflationary for accounting purposes. At June 30, 2020, we had net monetary assets denominated in Argentine pesos of $25.0 million (including cash of $21.1 million). At June 30, 2020, we had net nonmonetary assets of $149.2 million (including $99.8 million of goodwill). At June 30, 2020, we had no equity securities denominated in Argentine pesos. During September 2019, the Argentine government announced currency controls on both companies and individuals. The Argentine central bank issued details as to how the exchange control procedures would operate in practice. Under these procedures, central bank approval is required for many transactions, including dividend repatriation abroad. We have in the past and may elect in the future to utilize other market mechanisms to convert Argentine pesos into U.S. dollars. Conversions under these other market mechanisms have settled at rates that are generally less favorable than the rates at which we remeasured the financial statements of Brink's Argentina. We did not have any such conversions losses in the six months ended June 30, 2020. Although the Argentine government has implemented currency controls, Brink’s management continues to provide guidance and strategic oversight, including budgeting and forecasting for Brink’s Argentina. We continue to control our Argentina business for purposes of consolidation of our financial statements and continue to monitor the situation in Argentina. Venezuela Our Venezuelan operations offer transportation and route-based logistics management services for cash and valuables throughout Venezuela. Currency exchange regulations, combined with other government regulations, such as price controls and strict labor laws, significantly limit our ability to make and execute operational decisions at our Venezuelan subsidiaries. As a result of these conditions, we do not meet the accounting criteria for control over our Venezuelan operations and, as a result, we report the results of our investment in our Venezuelan subsidiaries using the cost method of accounting, the basis of which approximates zero. Prior to the imposition of the U.S. government sanctions in 2019, we provided immaterial amounts of financial support to our Venezuela operations. We continue to monitor the situation in Venezuela, including the imposition of sanctions by the U.S. government targeting Venezuela.
New Accounting Standards	New Accounting Standards In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842), which requires the recognition of right-of-use assets and lease liabilities by lessees for certain leases classified as operating leases and also requires expanded disclosures regarding leasing activities. The accounting for financing leases (previously "capital leases") remains substantially unchanged. We adopted the standard effective January 1, 2019 and elected to adopt the new standard at the adoption date through a cumulative-effect adjustment to the opening balance of retained earnings. Under this approach, we will continue to report comparative periods under ASC 840. We elected the package of practical expedients permitted under the transition guidance within the new standard, which among other things, allowed us to carry forward the historical lease classification. We also made an accounting policy election to exclude leases with an initial term of 12 months or less from the condensed consolidated balance sheet. We recognize those lease payments in the condensed consolidated statements of operations on a straight-line basis over the lease term. As part of this adoption, we implemented internal controls and key system functionality to enable the preparation of financial information. The adoption of the standard resulted in recording right-of-use assets of $310.1 million and lease liabilities of $320.3 million as of January 1, 2019. The right-of-use assets are lower than the lease liabilities as existing deferred rent and lease incentive liabilities were recorded as a reduction of the right-of-use assets at adoption in accordance with the standard. The standard did not affect our condensed consolidated statements of operations or our condensed consolidated statements of cash flows and did not result in a cumulative-effect adjustment to the opening balance of retained earnings. The standard had no impact on our debt-covenant compliance under our current agreements. In February 2018, the FASB issued ASU 2018-02, Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income, which allows a reclassification from accumulated other comprehensive income to retained earnings for stranded tax effects resulting from the Tax Cuts and Jobs Act of 2017 (“Tax Reform Act”). We adopted ASU 2018-02 effective January 1, 2019 and elected to recognize a cumulative-effect adjustment increasing retained earnings by $28.8 million related to the change in the U.S. federal corporate tax rate. In August 2018, the FASB issued ASU 2018-13, Disclosure Framework—Changes to the Disclosure Requirements for Fair Value Measurement, which changes the fair value measurement disclosure requirements. The amendments in this ASU eliminate some disclosures that are no longer considered cost beneficial, modify/clarify the specific requirements of certain disclosures and add disclosure requirements for Level 3 fair value measurements. We adopted ASU 2018-13 effective January 1, 2020 and the standard did not have a significant impact on our financial statements. In June 2016, the FASB issued ASU 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, which changes the way entities recognize impairment of many financial assets. This new guidance requires immediate recognition of estimated credit losses expected to occur over the life of the asset and incorporates estimated, forward-looking data when measuring lifetime Estimated Credit Losses (ECL). The standard was designed to provide greater transparency and understanding of credit risk by requiring enhanced financial statement disclosures which fall into three general categories: ECL estimate methodology and assumptions, quantitative information and metrics, and policy and process explanations. We adopted the standard using the modified retrospective transition method. Results for the reporting period beginning January 1, 2020 are presented under ASC 326 while prior period amounts continue to be reported in accordance with previously applicable GAAP. We recognized a cumulative-effect adjustment decreasing retained earnings by $1.7 million on January 1, 2020. The adoption of the standard also resulted in expanded disclosures related to credit losses (see Note 10). In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes, which removes certain exceptions for recognizing deferred taxes for investments, performing intraperiod tax allocations and calculating income taxes in interim periods. The ASU also adds guidance to reduce complexity in certain areas, including recognizing deferred taxes for tax goodwill and allocating taxes to members of a consolidated group. ASU 2019-12 will be effective for us on January 1, 2021. We are currently evaluating the impact it will have on our financial statements.