Business	9 Months Ended
Jun. 30, 2020
Accounting Policies [Abstract]
Business Description and Basis of Presentation [Text Block]	1. BUSINESS AND ACCOUNTING POLICIES Description of the Business IES Holdings, Inc. is a holding company that owns and manages operating subsidiaries in business activities across a variety of end-markets. Our operations are currently organized into four principal business segments, based upon the nature of our current services: •Commercial & Industrial – Provider of electrical and mechanical design, construction, and maintenance services to the commercial and industrial markets in various regional markets and nationwide in certain areas of expertise, such as the power infrastructure market and data centers •Communications – Nationwide provider of technology services, including the design, build, and maintenance of the infrastructure within data centers for co-location and managed hosting customers for both large corporations and independent businesses. •Infrastructure Solutions – Provider of electro-mechanical solutions for industrial operations, including apparatus repair and custom-engineered products such as generator enclosures used in data centers and other industrial applications. •Residential – Regional provider of electrical installation services for single-family housing and multi-family apartment complexes. The words “IES”, the “Company”, “we”, “our”, and “us” refer to IES Holdings, Inc. and, except as otherwise specified herein, to our consolidated subsidiaries. Seasonality and Quarterly Fluctuations Results of operations from our Residential construction segment can be seasonal, depending on weather trends, with typically higher revenues generated during spring and summer and lower revenues generated during fall and winter. The Commercial & Industrial, Communications and Infrastructure Solutions segments of our business are less subject to seasonal trends, as work in these segments generally is performed inside structures protected from the weather, although weather can still impact these businesses, especially in the early stages of projects. Our service and maintenance business is generally not affected by seasonality. Our volume of business may be adversely affected by declines in construction projects resulting from adverse regional or national economic conditions. Quarterly results may also be materially affected by the timing of new construction projects. Results for our Infrastructure Solutions segment may be affected by the timing of outages at our customers’ facilities. Accordingly, operating results for any fiscal period are not necessarily indicative of results that may be achieved for any subsequent fiscal period. Basis of Financial Statement Preparation The accompanying unaudited Condensed Consolidated Financial Statements include the accounts of IES, our wholly-owned subsidiaries, and entities that we control due to ownership of a majority of voting interest and have been prepared in accordance with the instructions to interim financial reporting as prescribed by the United States Securities and Exchange Commission (the “SEC”). The results for the interim periods are not necessarily indicative of results for the entire year. These interim financial statements do not include all disclosures required by U.S. generally accepted accounting principles (“GAAP”), and should be read in conjunction with the consolidated financial statements and notes thereto filed with the SEC in our Annual Report on Form 10-K for the fiscal year ended September 30, 2019. In the opinion of management, the unaudited Condensed Consolidated Financial Statements contained in this report include all known accruals and adjustments necessary for a fair presentation of the financial position, results of operations, and cash flows for the periods reported herein. Any such adjustments are of a normal recurring nature. Noncontrolling Interest In connection with our acquisitions of STR Mechanical, LLC in fiscal 2016 and NEXT Electric, LLC (“NEXT Electric”) in fiscal 2017, we acquired an 80 percent interest in each of the entities, with the remaining 20 percent interest in each such entity being retained by the respective third party seller. The interests retained by those third party sellers are identified on our Condensed Consolidated Balance Sheets as noncontrolling interest, classified outside of permanent equity. Under the terms of each entity’s operating agreement, after five years from the date of the acquisition, we may elect to purchase, or the third party seller may require us to purchase, part or all of the remaining 20 percent interest in the applicable entity. The purchase price is variable, based on a multiple of earnings as defined in the operating agreements. Therefore, this noncontrolling interest is carried at the greater of the balance determined under Accounting Standards Codification (“ASC”) 810 and the redemption amounts assuming the noncontrolling interests were redeemable at the balance sheet date. If all of these interests had been redeemable at June 30, 2020, the redemption amount would have been $2,438. Leases We enter into various contractual arrangements for the right to use facilities, vehicles and equipment. We evaluate whether each of these arrangements contains a lease and classify all identified leases as either operating or finance. If the arrangement is subsequently modified, we re-evaluate our classification. The lease term generally ranges from two to ten years for facilities and three to five years for vehicles and equipment. Our lease terms may include the exercise of renewal or termination options when it is reasonably certain these options will be exercised. Our lease agreements do not contain any material residual value guarantees or restrictive covenants. Upon commencement of the lease, we recognize a lease liability and corresponding right-of use ("ROU") asset for all leases with an initial term greater than twelve months. Lease liabilities represent the present value of our future lease payments over the expected lease term. As most of our leases do not provide an implicit rate, we generally use our incremental borrowing rate as the discount rate in calculating the present value of the lease payments. The incremental borrowing rate is determined by identifying a synthetic credit rating for the consolidated company, where treasury functions are centrally managed, and adjusting the interest rates from associated indexes for differences in credit risk and interest rate risk. We have elected to combine the lease and nonlease components in the recognition of our lease liabilities across all classes of underlying assets. ROU assets represent our right to control the use of the leased asset during the lease and are recognized in an amount equal to the lease liability with adjustments for prepaid or accrued rent, lease incentives or unamortized initial direct costs. Costs associated with operating lease assets are recognized on a straight-line basis over the term of the lease. Our lease assets are tested for impairment in the same manner as long-lived assets used in operations. Certain lease contracts include obligations to pay for other services, such as operations and maintenance. Where the costs of these services can be identified as fixed or fixed-in-substance, the costs are included as part of the future lease payments. If the cost is not fixed at the inception of the lease, the cost is recorded as a variable cost in the period incurred. Use of Estimates The preparation of financial statements in conformity with GAAP requires the use of estimates and assumptions by management in determining the reported amounts of assets and liabilities, disclosures of contingent liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Estimates are primarily used in our revenue recognition of construction in progress, fair value assumptions in accounting for business combinations and analyzing goodwill, intangible assets and long-lived asset impairments and adjustments, allowance for doubtful accounts receivable, stock-based compensation, reserves for legal matters, realizability of deferred tax assets, unrecognized tax benefits and self-insured claims liabilities and related reserves. Accounting Standards Not Yet Adopted In June 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standard Update No. 2016-13, Financial Instruments – Credit Losses (“ASU 2016-13”), which requires companies to consider historical experiences, current market conditions and reasonable and supportable forecasts in the measurement of expected credit losses, with further clarifications made in April 2019 and May 2019 with the issuances of Accounting Standard Updates No. 2019-04 and 2019-05. This update is effective for fiscal years beginning after December 15, 2019 and for interim periods within those fiscal years, although early adoption is permitted. We plan to adopt this standard on October 1, 2020, and do not expect the adoption to have a material effect on our Condensed Consolidated Financial Statements. In August 2018, the FASB issued Accounting Standard Update No. 2018-13, Fair Value Measurement Disclosure Framework (“ASU 2018-13”), to modify certain disclosure requirements for fair value measurements. Under the new guidance, registrants will need to disclose weighted average information for significant unobservable inputs for all Level 3 fair value measurements. The guidance does not specify how entities should calculate the weighted average, but requires them to explain their calculation. The new guidance also requires disclosing the changes in unrealized gains and losses for the period included in other comprehensive income for recurring Level 3 fair value measurements of instruments held at the end of the reporting period. This guidance is effective for fiscal years beginning after December 15, 2019 and for interim periods within those fiscal years, although early adoption is permitted for either the entire standard or only the provisions that eliminate or modify the requirements. We plan to adopt this standard on October 1, 2020, and do not expect the adoption to have a material effect on our Condensed Consolidated Financial Statements. Accounting Standards Recently Adopted In February 2016, the FASB issued Accounting Standard Update No. 2016-02, Leases (“ASU 2016-02”). Under ASU 2016-02, lessees need to recognize a ROU asset and a lease liability on the our Condensed Consolidated Balance Sheet for all leases, other than those that meet the definition of a short-term lease. For income statement purposes, leases must be classified as either operating or finance. Operating leases result in straight-line expense, while finance leases are accounted for similar to capital leases under the previous lease accounting standard. We adopted ASU 2016-02 on October 1, 2019 using a modified retrospective transition approach. Using the optional transition method allowed under Accounting Standard Update No. 2018-11, prior period amounts were not adjusted retrospectively and continue to be reported using the previous accounting standards in effect for the period presented. We elected to utilize all of the available practical expedients with the exception of the practical expedient permitting the use of hindsight when determining the lease term and assessing impairment of ROU assets. Therefore, we did not reassess whether any of our existing or expired contracts contained leases or the classification of or initial direct costs included in our existing or expired leases. The adoption of ASU 2016-02 resulted in the recognition of ROU assets of approximately $32,434 and operating lease liabilities of approximately $32,237 on our Condensed Consolidated Balance Sheet at the adoption date. The difference between the ROU assets and lease liabilities was primarily due to previously accrued rent expense relating to periods prior to October 1, 2019. The adoption did not have a significant impact on our Condensed Consolidated Statements of Comprehensive Income or Cash Flows. See Note 13, “Leases” for additional discussion of our lease accounting policies and expanded disclosures. In June 2018, the FASB issued Accounting Standard Update No. 2018-07, Compensation—Stock Compensation (“ASU 2018-07”), to simplify the accounting for share-based payments to nonemployees by aligning it with the accounting for share-based payments for employees, with certain exceptions. Under the new guidance, the cost for nonemployee awards may be lower and less volatile than under current GAAP because the measurement generally will occur earlier and will be fixed at the grant date. This update was adopted as of October 1, 2019 with no impact to our financial statements.

•Commercial & Industrial – Provider of electrical and mechanical design, construction, and maintenance services to the commercial and industrial markets in various regional markets and nationwide in certain areas of expertise, such as the power infrastructure market and data centers

Results of operations from our Residential construction segment can be seasonal, depending on weather trends, with typically higher revenues generated during spring and summer and lower revenues generated during fall and winter. The Commercial & Industrial, Communications and Infrastructure Solutions segments of our business are less subject to seasonal trends, as work in these segments generally is performed inside structures protected from the weather, although weather can still impact these businesses, especially in the early stages of projects. Our service and maintenance business is generally not affected by seasonality. Our volume of business may be adversely affected by declines in construction projects resulting from adverse regional or national economic conditions. Quarterly results may also be materially affected by the timing of new construction projects. Results for our Infrastructure Solutions segment may be affected by the timing of outages at our customers’ facilities. Accordingly, operating results for any fiscal period are not necessarily indicative of results that may be achieved for any subsequent fiscal period.

The accompanying unaudited Condensed Consolidated Financial Statements include the accounts of IES, our wholly-owned subsidiaries, and entities that we control due to ownership of a majority of voting interest and have been prepared in accordance with the instructions to interim financial reporting as prescribed by the United States Securities and Exchange Commission (the “SEC”). The results for the interim periods are not necessarily indicative of results for the entire year. These interim financial statements do not include all disclosures required by U.S. generally accepted accounting principles (“GAAP”), and should be read in conjunction with the consolidated financial statements and notes thereto filed with the SEC in our Annual Report on Form 10-K for the fiscal year ended September 30, 2019. In the opinion of management, the unaudited Condensed Consolidated Financial Statements contained in this report include all known accruals and adjustments necessary for a fair presentation of the financial position, results of operations, and cash flows for the periods reported herein. Any such adjustments are of a normal recurring nature.

In connection with our acquisitions of STR Mechanical, LLC in fiscal 2016 and NEXT Electric, LLC (“NEXT Electric”) in fiscal 2017, we acquired an 80 percent interest in each of the entities, with the remaining 20 percent interest in each such entity being retained by the respective third party seller. The interests retained by those third party sellers are identified on our Condensed Consolidated Balance Sheets as noncontrolling interest, classified outside of permanent equity. Under the terms of each entity’s operating agreement, after five years from the date of the acquisition, we may elect to purchase, or the third party seller may require us to purchase, part or all of the remaining 20 percent interest in the applicable entity. The purchase price is variable, based on a multiple of earnings as defined in the operating agreements. Therefore, this noncontrolling interest is carried at the greater of the balance determined under Accounting Standards Codification (“ASC”) 810 and the redemption amounts assuming the noncontrolling interests

We enter into various contractual arrangements for the right to use facilities, vehicles and equipment. We evaluate whether each of these arrangements contains a lease and classify all identified leases as either operating or finance. If the arrangement is subsequently modified, we re-evaluate our classification. The lease term generally ranges from two to ten years for facilities and three to five years for vehicles and equipment. Our lease terms may include the exercise of renewal or termination options when it is reasonably certain these options will be exercised. Our lease agreements do not contain any material residual value guarantees or restrictive covenants.

Upon commencement of the lease, we recognize a lease liability and corresponding right-of use ("ROU") asset for all leases with an initial term greater than twelve months. Lease liabilities represent the present value of our future lease payments over the expected lease term. As most of our leases do not provide an implicit rate, we generally use our incremental borrowing rate as the discount rate in calculating the present value of the lease payments. The incremental borrowing rate is determined by identifying a synthetic credit rating for the consolidated company, where treasury functions are centrally managed, and adjusting the interest rates from associated indexes for differences in credit risk and interest rate risk. We have elected to combine the lease and nonlease components in the recognition of our lease liabilities across all classes of underlying assets. ROU assets represent our right to control the use of the leased asset during the lease and are recognized in an amount equal to the lease liability with adjustments for prepaid or accrued rent, lease incentives or unamortized initial direct costs. Costs associated with operating lease assets are recognized on a straight-line basis over the term of the lease. Our lease assets are tested for impairment in the same manner as long-lived assets used in operations.

Certain lease contracts include obligations to pay for other services, such as operations and maintenance. Where the costs of these services can be identified as fixed or fixed-in-substance, the costs are included as part of the future lease payments. If the cost is not fixed at the inception of the lease, the cost is recorded as a variable cost in the period incurred.

The preparation of financial statements in conformity with GAAP requires the use of estimates and assumptions by management in determining the reported amounts of assets and liabilities, disclosures of contingent liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Estimates are primarily used in our revenue recognition of construction in progress, fair value assumptions in accounting for business combinations and analyzing goodwill, intangible assets and long-lived asset impairments and adjustments, allowance for doubtful accounts receivable, stock-based compensation, reserves for legal matters, realizability of deferred tax assets, unrecognized tax benefits and self-insured claims liabilities and related reserves.

In June 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standard Update No. 2016-13, Financial Instruments – Credit Losses (“ASU 2016-13”), which requires companies to consider historical experiences, current market conditions and reasonable and supportable forecasts in the measurement of expected credit losses, with further clarifications made in April 2019 and May 2019 with the issuances of Accounting Standard Updates No. 2019-04 and 2019-05. This update is effective for fiscal years beginning after December 15, 2019 and for interim periods within those fiscal years, although early adoption is permitted. We plan to adopt this standard on October 1, 2020, and do not expect the adoption to have a material effect on our Condensed Consolidated Financial Statements.

In August 2018, the FASB issued Accounting Standard Update No. 2018-13, Fair Value Measurement Disclosure Framework (“ASU 2018-13”), to modify certain disclosure requirements for fair value measurements. Under the new guidance, registrants will need to disclose weighted average information for significant unobservable inputs for all Level 3 fair value measurements. The guidance does not specify how entities should calculate the weighted average, but requires them to explain their calculation. The new guidance also requires disclosing the changes in unrealized gains and losses for the period included in other comprehensive income for recurring Level 3 fair value measurements of instruments held at the end of the reporting period. This guidance is effective for fiscal years beginning after December 15, 2019 and for interim periods within those fiscal years, although early adoption is permitted for either the entire standard or only the provisions that eliminate or modify the requirements. We plan to adopt this standard on October 1, 2020, and do not expect the adoption to have a material effect on our Condensed Consolidated Financial Statements.

In February 2016, the FASB issued Accounting Standard Update No. 2016-02, Leases (“ASU 2016-02”). Under ASU 2016-02, lessees need to recognize a ROU asset and a lease liability on the our Condensed Consolidated Balance Sheet for all leases, other than those that meet the definition of a short-term lease. For income statement purposes, leases must be classified as either operating or finance. Operating leases result in straight-line expense, while finance leases are accounted for similar to capital leases under the previous lease accounting standard. We adopted ASU 2016-02 on October 1, 2019 using a modified retrospective transition approach. Using the optional transition method allowed under Accounting Standard Update No. 2018-11, prior period amounts were not adjusted retrospectively and continue to be reported using the previous accounting standards in effect for the period presented. We elected to utilize all of the available practical expedients with the exception of the practical expedient permitting the use of hindsight when determining the lease term and assessing impairment of ROU assets. Therefore, we did not reassess whether any of our existing or expired contracts contained leases or the classification of or initial direct costs included in our existing or expired leases.

The adoption of ASU 2016-02 resulted in the recognition of ROU assets of approximately $32,434 and operating lease liabilities of approximately $32,237 on our Condensed Consolidated Balance Sheet at the adoption date. The difference between the ROU assets and lease liabilities was primarily due to previously accrued rent expense relating to periods prior to October 1, 2019. The adoption did not have a significant impact on our Condensed Consolidated Statements of Comprehensive Income or Cash Flows. See Note 13, “Leases” for additional discussion of our lease accounting policies and expanded disclosures.

In June 2018, the FASB issued Accounting Standard Update No. 2018-07, Compensation—Stock Compensation (“ASU 2018-07”), to simplify the accounting for share-based payments to nonemployees by aligning it with the accounting for share-based payments for employees, with certain exceptions. Under the new guidance, the cost for nonemployee awards may be lower and less volatile than under current GAAP because the measurement generally will occur earlier and will be fixed at the grant date. This update was adopted as of October 1, 2019 with no impact to our financial statements.