Significant Accounting Policies (Policies)	6 Months Ended
Significant Accounting Policies (Policies)	Mar. 31, 2020
Accounting Policies [Abstract]
Basis of Accounting, Policy [Policy Text Block]	Basis of presentation The unaudited consolidated condensed financial statements include the accounts of ADDvantage Technologies Group, Inc. and its subsidiaries, all of which are wholly owned (collectively, the “Company” or “we”). Intercompany balances and transactions have been eliminated in consolidation. The Company’s reportable segments are Wireless Infrastructure Services (“Wireless”) and Telecommunications (“Telco”). The accompanying unaudited consolidated condensed financial statements have been prepared in accordance with accounting principles generally accepted in the United States for interim financial statements and do not include all the information and footnotes required by accounting principles generally accepted in the United States for complete financial statements. However, the information furnished reflects all adjustments, which are, in the opinion of management, necessary in order to make the unaudited consolidated condensed financial statements not misleading. The Company’s business is subject to certain seasonal variations due to weather in the geographic areas that services are performed, and to a certain extent due to calendar events and national holidays. Therefore, the results of operations for the six months ended March 31, 2020 and 2019, are not necessarily indicative of the results to be expected for the full fiscal year. It is suggested that these unaudited consolidated condensed financial statements be read in conjunction with the audited consolidated financial statements and the notes thereto included in the Company’s Annual Report on Form 10 -K for the fiscal year ended September 30, 2019.
Reclassification, Comparability Adjustment [Policy Text Block]	Reclassification The Company changed its presentation of cost of sales and operating, selling, general and administrative expenses on the unaudited consolidated condensed statements of operations. During fiscal year 2020, the Company reviewed its financial reporting of expenses in connection with its current operating segments in order to enhance the usefulness of the presentation of the Company’s expenses. Based on that review, the Company reclassified certain expenses into operating expenses for presentation purposes. Operating expenses include the indirect costs associated with operating our businesses. Indirect costs are costs that are not directly attributable to projects or products, which would include indirect personnel costs, facility costs, vehicles, insurance, communication, and business taxes, among other less significant cost categories. These costs were previously recorded in either costs of sales or operating, selling, general and administrative expenses in prior periods. Additionally, the Company reclassified depreciation and amortization from operating, selling, general and administrative expenses into its own financial statement line item in the unaudited consolidated condensed statements of operations. Selling, general and administrative expenses include overhead costs, which primarily consist of personnel costs, insurance, professional services, and communication, among other less significant cost categories. The prior period has been reclassified to conform with the current period’s presentation of costs of sales, operating expenses, selling, general and administrative expenses, and depreciation and amortization. These reclassifications had no effect on previously reported results of operations or retained earnings.
New Accounting Pronouncements, Policy [Policy Text Block]	Recently Issued Accounting Standards In June 2016, the FASB issued ASU 2016 - 13: “Financial Instruments – Credit Losses (Topic 326 ) – Measurement of Credit Losses on Financial Instruments.” This ASU requires entities to measure all expected credit losses for most financial assets held at the reporting date based on an expected loss model which includes historical experience, current conditions, and reasonable and supportable forecasts. Entities will now use forward-looking information to better form their credit loss estimates. This ASU also requires enhanced disclosures to help financial statement users better understand significant estimates and judgments used in estimating credit losses, as well as the credit quality and underwriting standards of an entity’s portfolio. ASU 2016 - 13 is effective for annual periods beginning after December 15, 2019, including interim periods within those fiscal periods. Entities may adopt earlier as of the fiscal year beginning after December 15, 2018, including interim periods within those fiscal years. We are currently in the process of evaluating this new standard update.