Summary of Financial Statement Preparation and Significant Accounting Policies	9 Months Ended
Sep. 30, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Summary of Financial Statement Preparation and Significant Accounting Policies	SUMMARY OF FINANCIAL STATEMENT PREPARATION AND SIGNIFICANT ACCOUNTING POLICIES Nature of Operations Air Transport Services Group, Inc. is a holding company whose principal subsidiaries include an aircraft leasing company and two independently certificated airlines. The Company provides airline operations, aircraft leases, aircraft maintenance and other support services primarily to the cargo transportation and package delivery industries. Through the Company's subsidiaries, it offers a range of complementary services to delivery companies, freight forwarders, airlines and government customers. The Company's leasing subsidiary, Cargo Aircraft Management, Inc. (“CAM”), leases aircraft to each of the Company's airlines as well as to non-affiliated airlines and other lessees. The airlines, ABX Air, Inc. (“ABX”) and Air Transport International, Inc. (“ATI”), each have the authority, through their separate U.S. Department of Transportation ("DOT") and Federal Aviation Administration ("FAA") certificates, to transport cargo worldwide. ATI provides passenger transportation, primarily to the U.S. Military, using "combi" aircraft, which are certified to carry passengers as well as cargo on the main deck. The Company serves a base of concentrated customers who typically have a diverse line of international cargo traffic. The Company provides aircraft and airline operations to its customers, typically under contracts providing for a combination of aircraft, crews, maintenance and insurance ("ACMI") services. In addition to its airline operations and aircraft leasing services, the Company sells aircraft parts, provides aircraft and equipment maintenance services, and operates mail and package sorting facilities. Basis of Presentation The accompanying unaudited condensed interim consolidated financial statements are prepared in conformity with accounting principles generally accepted in the United States of America and such principles are applied on a basis consistent with the financial statements reflected in our Annual Report on Form 10-K for the fiscal year ended December 31, 2015 filed with the Securities and Exchange Commission (“SEC”). Certain information and footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States of America have been condensed or omitted pursuant to the rules and regulations promulgated by the SEC related to interim financial statements. In the opinion of management, the accompanying financial statements contain all adjustments, including normal recurring adjustments, necessary for the fair presentation of the Company’s results of operations and financial position for the periods presented. Due to seasonal fluctuations, among other factors common to the airline industry, the results of operations for the periods presented are not necessarily indicative of the results of operations to be expected for the entire year or any interim period. The preparation of consolidated financial statements requires management to make estimates and assumptions that affect amounts reported in the consolidated financial statements. The accounting estimates reflect the best judgment of management, but actual results could differ materially from those estimates. The accompanying condensed consolidated financial statements include the accounts of Air Transport Services Group, Inc. and its wholly-owned subsidiaries. Investments in an affiliate in which the Company has significant influence but does not exercise control are accounted for using the equity method of accounting. Using the equity method, the Company’s share of the nonconsolidated affiliate's income or loss is recognized in the consolidated statement of earnings and cumulative post-acquisition changes in the investment are adjusted against the carrying amount of the investment. Inter-company balances and transactions are eliminated. New Accounting Pronouncements In March 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-09, "Improvements to Employee Share-Based Payment Accounting," (“ASU 2016-09”) which addresses several aspects of the accounting for employee share-based payment transactions, including the accounting for income taxes, forfeitures, and statutory tax withholding requirements, as well as classification in the statement of cash flows. ASU 2016-9 is effective for annual reporting periods beginning after December 15, 2016 and earlier adoption is permitted. The new standard requires that an entity recognize all excess tax benefits and tax deficiencies as income tax expense or benefit in the income statement as discrete items in the reporting period in which they occur. Under the previous standard, excess tax benefits are recognized in additional paid-in capital and tax deficiencies are recognized either as an offset to accumulated excess tax benefits, or in the income statement. The Company elected to early adopt this standard in the quarter ended March 31, 2016. The impact of the early adoption resulted in the Company recording a tax benefit of $0.7 million within income tax expense for the three months ended March 31, 2016 related to the excess tax benefit on stock incentive awards that settled during the quarter ended March 31, 2016. The tax benefit for the nine months ended September 30, 2016 was $0.7 million. Prior to adoption of ASU 2016-09, this amount would have been recorded as an increase of additional paid-in capital. The tax benefit for the nine months ended September 30, 2015 would have been $0.4 million. The Company accounts for forfeitures as they occur. Under ASU 2016-09, excess tax benefits related to employee share-based payments are not reclassified from operating activities to financing activities in the statement of cash flows. The Company applied the effect of ASU 2016-09 to the presentation of excess tax benefits in the statement of cash flows, prospectively. Under ASU 2016-09, cash paid when withholding shares for tax withholding purposes are classified as a financing activity in the statement of cash flows. The Company has applied the effect of this change on prior period statements of cash flows retrospectively. The Company excluded the excess tax benefits from the assumed proceeds available to repurchase shares in the computation of our diluted earnings per share for the quarter ended September 30, 2016. This increased the diluted weighted average common shares outstanding by 151,421 shares. In May 2014, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") No. 2014-09, “Revenue from Contracts with Customers (Topic 606)” (“ASU 2014-09”). ASU 2014-09 is a comprehensive new revenue recognition model that requires a company to recognize revenue to depict the transfer of goods or services to a customer at an amount that reflects the consideration it expects to receive in exchange for those goods or services. ASU 2014-09 also requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts, including significant judgments and changes in judgments and assets recognized from costs incurred to obtain or fulfill a contract. ASU 2014-09 is effective for annual reporting periods beginning after December 15, 2017 with earlier adoption permitted for reporting periods beginning after December 15, 2016. The Company is currently evaluating the methods of adoption allowed by the new standard and the effect the standard is expected to have on the Company's consolidated financial position, results of operations or cash flows and related disclosures. In April 2015, the FASB issued ASU 2015-03, "Interest - Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs" ("ASU 2015-03"). ASU 2015-03 requires debt issuance costs related to a recognized debt liability to be presented in the balance sheet as a direct deduction from the carrying value of that debt liability, consistent with debt discounts. The recognition and measurement guidance for debt issuance costs are not affected by ASU 2015-03. The amendments in ASU 2015-03 are effective retrospectively for fiscal years, and interim periods within those years, beginning after December 15, 2015. As a result of the adoption of ASU 2015-03, the amounts of debt issuance costs were reclassified on the Company's balance sheets from other assets to long term debt. In July 2015, FASB issued ASU 2015-11, "Inventory (Topic 330): Simplifying the Measurement of Inventory" ("ASU 2015-11"). ASU 2015-11 more closely aligns the measurement of inventory in GAAP with the measurement of inventory in International Financial Reporting Standards ("IFRS"). The amendment in ASU 2015-11 is for fiscal years beginning after December 15, 2016, and interim periods within fiscal years beginning after December 15, 2017. The amendment should be applied prospectively with earlier application permitted as of the beginning of an interim or annual reporting period. The Company does not expect the impact of adopting ASU 2015-11 to be material to the Company's financial statements and related disclosures. In February 2016, the FASB issued ASU 2016-02, "Leases (Topic 842)" which will require the recognition of right to-use-assets and lease liabilities for leases previously classified as operating leases by lessees. The standard will take effect for annual reporting periods beginning after December 15, 2018, including interim reporting periods. Early application will be permitted for all entities. In addition, the FASB has decided to require a lessee to apply a modified retrospective transition approach for capital and operating leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements (the date of initial application). The modified retrospective approach would not require any transition accounting for leases that expired before the date of initial application. The FASB decided to not permit a full retrospective transition approach. The Company is currently evaluating the impact of the standard on its financial statements and disclosures. In January 2016, the FASB issued an Exposure Draft of a proposed ASU, "Compensation - Retirement Benefits (Topic 715) Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost." The proposed ASU would require an employer to report the service cost component of retiree benefits in the same line item or items as other compensation costs arising from services rendered by the pertinent employees during the period. The other components of net benefit cost would be presented in the income statement separately from the service cost component and outside a subtotal of income from operations, if one is presented. If adopted, the proposed standard would impact the Operating Income subtotal as reported in the Company's Consolidated Statement of Operations by excluding interest expense and investment returns components of retiree benefit expenses.

SUMMARY OF FINANCIAL STATEMENT PREPARATION AND SIGNIFICANT ACCOUNTING POLICIES

Nature of Operations

Air Transport Services Group, Inc. is a holding company whose principal subsidiaries include an aircraft leasing company and two independently certificated airlines. The Company provides airline operations, aircraft leases, aircraft maintenance and other support services primarily to the cargo transportation and package delivery industries. Through the Company's subsidiaries, it offers a range of complementary services to delivery companies, freight forwarders, airlines and government customers.

The Company's leasing subsidiary, Cargo Aircraft Management, Inc. (“CAM”), leases aircraft to each of the Company's airlines as well as to non-affiliated airlines and other lessees. The airlines, ABX Air, Inc. (“ABX”) and Air Transport International, Inc. (“ATI”), each have the authority, through their separate U.S. Department of Transportation ("DOT") and Federal Aviation Administration ("FAA") certificates, to transport cargo worldwide. ATI provides passenger transportation, primarily to the U.S. Military, using "combi" aircraft, which are certified to carry passengers as well as cargo on the main deck.

The Company serves a base of concentrated customers who typically have a diverse line of international cargo traffic. The Company provides aircraft and airline operations to its customers, typically under contracts providing for a combination of aircraft, crews, maintenance and insurance ("ACMI") services. In addition to its airline operations and aircraft leasing services, the Company sells aircraft parts, provides aircraft and equipment maintenance services, and operates mail and package sorting facilities.

Basis of Presentation

The accompanying unaudited condensed interim consolidated financial statements are prepared in conformity with accounting principles generally accepted in the United States of America and such principles are applied on a basis consistent with the financial statements reflected in our Annual Report on Form 10-K for the fiscal year ended December 31, 2015 filed with the Securities and Exchange Commission (“SEC”). Certain information and footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States of America have been condensed or omitted pursuant to the rules and regulations promulgated by the SEC related to interim financial statements. In the opinion of management, the accompanying financial statements contain all adjustments, including normal recurring adjustments, necessary for the fair presentation of the Company’s results of operations and financial position for the periods presented. Due to seasonal fluctuations, among other factors common to the airline industry, the results of operations for the periods presented are not necessarily indicative of the results of operations to be expected for the entire year or any interim period. The preparation of consolidated financial statements requires management to make estimates and assumptions that affect amounts reported in the consolidated financial statements. The accounting estimates reflect the best judgment of management, but actual results could differ materially from those estimates.

The accompanying condensed consolidated financial statements include the accounts of Air Transport Services Group, Inc. and its wholly-owned subsidiaries. Investments in an affiliate in which the Company has significant influence but does not exercise control are accounted for using the equity method of accounting. Using the equity method, the Company’s share of the nonconsolidated affiliate's income or loss is recognized in the consolidated statement of earnings and cumulative post-acquisition changes in the investment are adjusted against the carrying amount of the investment. Inter-company balances and transactions are eliminated.

New Accounting Pronouncements

In March 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-09, "Improvements to Employee Share-Based Payment Accounting," (“ASU 2016-09”) which addresses several aspects of the accounting for employee share-based payment transactions, including the accounting for income taxes, forfeitures, and statutory tax withholding requirements, as well as classification in the statement of cash flows. ASU 2016-9 is effective for annual reporting periods beginning after December 15, 2016 and earlier adoption is permitted. The new standard requires that an entity recognize all excess tax benefits and tax deficiencies as income tax expense or benefit in the income statement as discrete items in the reporting period in which they occur. Under the previous standard, excess tax benefits are recognized in additional paid-in capital and tax deficiencies are recognized either as an offset to accumulated excess tax benefits, or in the income statement.

The Company elected to early adopt this standard in the quarter ended March 31, 2016. The impact of the early adoption resulted in the Company recording a tax benefit of $0.7 million within income tax expense for the three months ended March 31, 2016 related to the excess tax benefit on stock incentive awards that settled during the quarter ended March 31, 2016. The tax benefit for the nine months ended September 30, 2016 was $0.7 million. Prior to adoption of ASU 2016-09, this amount would have been recorded as an increase of additional paid-in capital. The tax benefit for the nine months ended September 30, 2015 would have been $0.4 million.

The Company accounts for forfeitures as they occur. Under ASU 2016-09, excess tax benefits related to employee share-based payments are not reclassified from operating activities to financing activities in the statement of cash flows. The Company applied the effect of ASU 2016-09 to the presentation of excess tax benefits in the statement of cash flows, prospectively. Under ASU 2016-09, cash paid when withholding shares for tax withholding purposes are classified as a financing activity in the statement of cash flows. The Company has applied the effect of this change on prior period statements of cash flows retrospectively. The Company excluded the excess tax benefits from the assumed proceeds available to repurchase shares in the computation of our diluted earnings per share for the quarter ended September 30, 2016. This increased the diluted weighted average common shares outstanding by 151,421 shares.

In May 2014, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") No. 2014-09, “Revenue from Contracts with Customers (Topic 606)” (“ASU 2014-09”). ASU 2014-09 is a comprehensive new revenue recognition model that requires a company to recognize revenue to depict the transfer of goods or services to a customer at an amount that reflects the consideration it expects to receive in exchange for those goods or services. ASU 2014-09 also requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts, including significant judgments and changes in judgments and assets recognized from costs incurred to obtain or fulfill a contract. ASU 2014-09 is effective for annual reporting periods beginning after December 15, 2017 with earlier adoption permitted for reporting periods beginning after December 15, 2016. The Company is currently evaluating the methods of adoption allowed by the new standard and the effect the standard is expected to have on the Company's consolidated financial position, results of operations or cash flows and related disclosures.

In April 2015, the FASB issued ASU 2015-03, "Interest - Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs" ("ASU 2015-03"). ASU 2015-03 requires debt issuance costs related to a recognized debt liability to be presented in the balance sheet as a direct deduction from the carrying value of that debt liability, consistent with debt discounts. The recognition and measurement guidance for debt issuance costs are not affected by ASU 2015-03. The amendments in ASU 2015-03 are effective retrospectively for fiscal years, and interim periods within those years, beginning after December 15, 2015. As a result of the adoption of ASU 2015-03, the amounts of debt issuance costs were reclassified on the Company's balance sheets from other assets to long term debt.

In July 2015, FASB issued ASU 2015-11, "Inventory (Topic 330): Simplifying the Measurement of Inventory" ("ASU 2015-11"). ASU 2015-11 more closely aligns the measurement of inventory in GAAP with the measurement of inventory in International Financial Reporting Standards ("IFRS"). The amendment in ASU 2015-11 is for fiscal years beginning after December 15, 2016, and interim periods within fiscal years beginning after December 15, 2017. The amendment should be applied prospectively with earlier application permitted as of the beginning of an interim or annual reporting period. The Company does not expect the impact of adopting ASU 2015-11 to be material to the Company's financial statements and related disclosures.

In February 2016, the FASB issued ASU 2016-02, "Leases (Topic 842)" which will require the recognition of right to-use-assets and lease liabilities for leases previously classified as operating leases by lessees. The standard will take effect for annual reporting periods beginning after December 15, 2018, including interim reporting periods. Early application will be permitted for all entities. In addition, the FASB has decided to require a lessee to apply a modified retrospective transition approach for capital and operating leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements (the date of initial application). The modified retrospective approach would not require any transition accounting for leases that expired before the date of initial application. The FASB decided to not permit a full retrospective transition approach. The Company is currently evaluating the impact of the standard on its financial statements and disclosures.

In January 2016, the FASB issued an Exposure Draft of a proposed ASU, "Compensation - Retirement Benefits (Topic 715) Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost." The proposed ASU would require an employer to report the service cost component of retiree benefits in the same line item or items as other compensation costs arising from services rendered by the pertinent employees during the period. The other components of net benefit cost would be presented in the income statement separately from the service cost component and outside a subtotal of income from operations, if one is presented. If adopted, the proposed standard would impact the Operating Income subtotal as reported in the Company's Consolidated Statement of Operations by excluding interest expense and investment returns components of retiree benefit expenses.