The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America (“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 credit losses, stock-based compensation, reserves for legal matters, realizability of deferred tax assets, unrecognized tax benefits and self-insured claims liabilities and related reserves.

Inventories consist of raw materials, work in process, finished goods, and parts and supplies held for use in the ordinary course of business. Inventory is valued at the lower of cost or net realizable value generally using the historical average cost or first-in, first-out (FIFO) method. When circumstances dictate, we write down inventory to its estimated net realizable value based on assumptions about future demand, market conditions, plans for disposal, and physical condition of the product. Where shipping and handling costs on inventory purchases are borne by us, these charges are included in inventory and charged to cost of services upon use in our projects or the providing of services.

Expenditures for repairs and maintenance are charged to expense when incurred. Expenditures for major renewals and betterments, which extend the useful lives of existing property and equipment, are capitalized and depreciated. Upon retirement or disposition of property and equipment, the capitalized cost and related accumulated depreciation are removed from the accounts and any resulting gain or loss is recognized in the statements of comprehensive income in the caption (gain) loss on sale of assets.

Goodwill attributable to each reporting unit is tested for impairment either by comparing the fair value of each reporting unit with its carrying value or by a qualitative assessment. These impairment tests are required to be performed at least annually. On an ongoing basis (absent any impairment indicators), we perform an impairment test annually using a measurement date of September 30. In evaluating goodwill for impairment, we have the option to first assess qualitative factors to determine whether it is more likely than not that the fair value of a reporting unit is greater than its carrying value. If we determine that it is more likely than not that the carrying value of a reporting unit is greater than its fair value, then we perform an impairment test by calculating the fair value of the reporting unit and comparing this calculated fair value with the carrying value of the reporting unit.

We estimate the fair value of the reporting unit based on both a market approach and an income approach, using discounted estimated future cash flows. The market approach uses market multiples of enterprise value to earnings before interest, taxes, depreciation and amortization for comparable publicly traded companies. The income approach relies on significant estimates for future cash flows, projected long-term growth rates, and the weighted average cost of capital.

Debt issuance costs are included as a reduction of our debt outstanding, or alternately classified within other non-current assets if we have no borrowings drawn on our credit facility at the balance sheet date, and are amortized to interest expense over the scheduled maturity of the debt. Amortization expense of debt issuance costs was $199, $198 and $152, respectively, for the years ended 2022, 2021 and 2020. Remaining unamortized capitalized debt issuance costs were $1,031 and $656 at September 30, 2022, and 2021, respectively.

Revenue is recognized from a contract with a customer when: (i) it has approval and commitment from both parties, (ii) the rights of the parties are identified, (iii) payment terms are identified, (iv) the contract has commercial substance, and (v) collectability of consideration is probable. We consider the start of a project to be when the above criteria have been met and we have written authorization from the customer to proceed.

We recognize revenue on project contracts over time using the percentage of completion method. Project contracts generally provide that customers accept completion of progress to date and compensate us for services rendered measured in terms of units installed, hours expended or some other measure of progress. We recognize revenue on both signed contracts and change orders. A discussion of our treatment of claims and unapproved change orders is described later in this section. Percentage of completion for construction contracts is measured principally by the percentage of costs incurred and accrued to date for each contract to the estimated total cost for each contract at completion. We generally consider contracts to be substantially complete upon departure from the work site and acceptance by the customer. Contract costs include all direct material, labor and insurance costs and those indirect costs related to contract performance, such as indirect labor, supplies, tools, repairs and depreciation costs. Changes in job performance, job conditions, estimated contract costs and profitability and final contract settlements can result in change orders under which the customer agrees to pay additional contract price. Revisions can also result in claims we might make against the customer to recover additional costs that have not been resolved through change orders with the customer. We do not recognize revenue or margin based on change orders or claims if it is probable such revenue will be reversed. The amount of revenue associated with unapproved change orders and claims was immaterial for the years ended September 30, 2022, 2021 and 2020. Provisions for total estimated losses on uncompleted contracts are made in the period in which such losses are determined. The balances billed but not paid by customers

Certain divisions in the Residential and Infrastructure Solutions segments recognize revenue as of a point-in-time at the completion of the contract ("completed contract") because the duration of their contracts is short in nature. We recognize revenue on completed contracts when the project is complete and billable to the customer. Provisions for estimated losses on these contracts are recorded in the period such losses are determined.

As described below under “Accounting Standards Recently Adopted”, we adopted the new accounting standard for measuring credit losses effective October 1, 2020. We record accounts receivable for all amounts billed and not collected and amounts for which we have an unconditional right to bill our customers. Additionally, we provide an allowance for credit losses based on historical company-specific uncollectable accounts, as well as current and expected market conditions. From time to time, we establish additional allowance for credit losses for financial asset balances with specific customers where collectability has been determined to be improbable based on specific facts and circumstances. Such allowances are established as deemed necessary in the period such determination is made. As is common in our industry, some of these receivables are in litigation or require us to exercise our contractual lien rights in order to collect. Our allowance for credit losses at September 30, 2022 and 2021 was $5,361 and $2,387, respectively.

We evaluate valuation allowances established for deferred tax assets for which future realization is uncertain on a quarterly basis. In assessing the realizability of deferred tax assets, we must consider whether it is more likely than not some portion, or all, of the deferred tax assets will not be realized. We consider all available evidence, both positive and negative, in determining whether a valuation allowance is required. At September 30, 2022, we concluded, based upon the assessment of positive and negative evidence, that it is more likely than not that the Company will generate sufficient taxable income within the applicable net operating loss ("NOL") carryforward periods to realize net deferred tax assets of $20,519. We considered the scheduled reversal of deferred tax liabilities, projected future taxable income and tax planning strategies in making this assessment. If actual future taxable income is different from these estimates, our results could be affected.

We record reserves for income taxes related to certain tax positions when management considers it more likely than not that additional taxes may be due in excess of amounts reflected on income tax returns filed. When recording these reserves, we assume that taxing authorities have full knowledge of the position and all relevant facts. We continually review exposure to additional tax obligations, and as further information is known or events occur, changes in tax reserves may be recorded. To the extent interest and penalties may be assessed by taxing authorities on any underpayment of income tax, such amounts have been accrued and included in the provision for income taxes.

We retain the risk for workers’ compensation, employer’s liability, automobile liability, construction defects, general liability and employee group health claims, as well as pollution coverage, resulting from uninsured deductibles per accident or occurrence which are generally subject to annual aggregate limits. Our general liability program provides coverage for bodily injury and property damage. In many cases, we insure third parties, including general contractors, as additional insureds under our insurance policies. Losses are accrued based upon our known claims incurred and an estimate of claims incurred but not reported. Each year, we compile our historical data pertaining to the insurance experiences and actuarially develop the ultimate loss associated with our insurance programs other than pollution coverage for our Infrastructure Solutions segment. We believe that the actuarial valuation provides the best estimate of the ultimate losses to be expected under these programs.

We elect to discount the ultimate losses above to present value using an approximate risk-free rate over the average life of our insurance claims. For the years ended September 30, 2022 and 2021, the discount rate used was 4.1 percent and 1.0 percent, respectively. The present value of all insurance reserves for the workers’ compensation, auto and general liability recorded at September 30, 2022 and 2021 was $5,042 and $3,234, respectively. Our undiscounted reserves for employee group health claims at September 30, 2022 and 2021 were $2,651 and $2,553, respectively, and are anticipated to be resolved within the year ending September 30, 2023.

We evaluate the recoverability of property and equipment and other long-lived assets as facts and circumstances indicate that any of those assets might be impaired. If an evaluation is required for our assets we plan to hold and use, the estimated future undiscounted cash flows associated with the asset are compared to the asset’s carrying amount to determine if an impairment of such property has occurred. The effect of any impairment would be to expense the difference between the fair value of such property and its carrying value. Estimated fair values are determined based on expected future cash flows discounted at a rate we believe incorporates the time value of money, the expectations about future cash flows and an appropriate risk premium.

Financial instruments, which potentially subject us to concentrations of credit risk, consist principally of cash deposits and accounts receivable. Through delayed payment terms, we at times grant credit, usually without collateral, to our customers, who are generally large public companies, contractors and homebuilders throughout the United States. Consequently, we are subject to potential credit risk related to changes in business and economic factors throughout the United States, specifically within the construction, homebuilding and mission critical facility markets. However, we are entitled to payment for work performed and generally have certain lien rights in that work. Further, management believes that its contract acceptance, billing and collection policies are adequate to manage potential credit risk. We routinely maintain cash balances in financial institutions in excess of federally insured limits. We periodically assess the financial condition of these institutions where these funds are held and believe the credit risk is minimal. We maintain the majority of our cash and cash equivalents in depository bank accounts or money market mutual funds. There can be no assurance, however, that we will not be adversely affected by credit risks we face.

In connection with our acquisitions of Edmonson Electric, LLC ("Edmonson") and Bayonet Plumbing, Heating & Air-Conditioning, LLC ("Bayonet") in fiscal 2021, NEXT Electric, LLC ("NEXT") in fiscal 2017, and STR Mechanical, LLC ("STR") in fiscal 2016, 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 sellers. The interests retained by those third party sellers are identified on our 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. During the year ended September 30, 2021, we acquired the noncontrolling interest in STR for $1,188. If all of the noncontrolling interests remaining outstanding at September 30, 2022 had been redeemable at that date, the redemption amount would have been $27,204. For the year ended September 30, 2022, we recorded a decrease to Retained Earnings of $4,699 to increase the carrying amount of noncontrolling interest in NEXT and Edmonson to their redemption amounts. For the year ended September 30, 2021, we recorded a decrease to Retained Earnings of $315 to increase the carrying amount of noncontrolling interest in NEXT and STR to their redemption amounts.

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 ROU 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.

In December 2019, the Financial Accounting Standards Board ("FASB") issued Accounting Standard Update No. 2019-12, “Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes.” This standard simplifies the accounting for income taxes by eliminating certain exceptions to the guidance in Topic 740 related to the approach for intraperiod tax allocation, the methodology for calculating income taxes in an interim period and the recognition of deferred tax liabilities for outside basis differences. The standard also simplifies aspects of the accounting for franchise taxes and enacted changes in tax laws or rates and clarifies the accounting for transactions that result in a step-up in the tax basis of goodwill. This update is effective for fiscal years beginning after December 15, 2020 and for interim periods within that year. Early adoption is permitted. We adopted this standard on October 1, 2021 with immaterial impact on our Consolidated Financial Statements.

In June 2016, 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. We adopted this standard on October 1, 2020, using a modified retrospective transition method through a cumulative-effect adjustment to beginning retained earnings in the period of adoption. As a result, we recorded an increase in the Allowance for Credit Losses of $284, an increase to Deferred Tax Assets of $70, and a decrease to Retained Earnings of $214.