Nature of Business	6 Months Ended
Nature of Business	Mar. 31, 2021
Accounting Policies [Abstract]
Nature of Business	Nature of Business Fair Isaac Corporation Incorporated under the laws of the State of Delaware, Fair Isaac Corporation (“FICO”) is a provider of analytic, software and data management products and services that enable businesses to automate, improve and connect decisions. FICO provides a range of analytic solutions, credit scoring and credit account management products and services to banks, credit reporting agencies, credit card processing agencies, insurers, retailers, healthcare organizations and public agencies. In this Quarterly Report on Form 10-Q, Fair Isaac Corporation is referred to as “FICO,” “we,” “us,” “our,” or “the Company.” Principles of Consolidation and Basis of Presentation We have prepared the accompanying unaudited interim condensed consolidated financial statements in accordance with the instructions to Form 10-Q and the applicable accounting guidance. Consequently, we have not necessarily included all information and footnotes required for audited financial statements. In our opinion, the accompanying unaudited interim condensed consolidated financial statements reflect all adjustments (consisting only of normal recurring adjustments, except as otherwise indicated) necessary for a fair presentation of our financial position and results of operations. These unaudited condensed consolidated financial statements and notes thereto should be read in conjunction with our audited consolidated financial statements and notes thereto presented in our Annual Report on Form 10-K for the fiscal year ended September 30, 2020. The interim financial information contained in this report is not necessarily indicative of the results to be expected for any other interim period or for the entire fiscal year. The condensed consolidated financial statements include the accounts of FICO and its subsidiaries. All intercompany accounts and transactions have been eliminated. Use of Estimates We make estimates and assumptions that affect the amounts reported in the financial statements and the disclosures made in the accompanying notes. For example, we use estimates in determining the collectibility of accounts receivable; the appropriate levels of various accruals; variable considerations included in the transaction price for our customer contracts; labor hours in connection with fixed-fee service contracts; the amount of our tax provision; and the realizability of deferred tax assets. We also use estimates in determining the remaining economic lives and carrying values of acquired intangible assets, property and equipment, and other long-lived assets. In addition, we use assumptions to estimate the fair value of reporting units and share-based compensation. Actual results may differ from our estimates. As the impact of the COVID-19 pandemic continues to evolve, estimates and assumptions about future events and their effects cannot be determined with certainty and therefore require increased judgment. These estimates and assumptions may change in future periods and will be recognized in the condensed consolidated financial statements as new events occur and additional information becomes known. To the extent our actual results differ materially from those estimates and assumptions, our future financial statements could be affected. For more information, see Part II, Item 1A “Risk Factors” of this Quarterly Report on Form 10-Q. New Accounting Pronouncements Recently Adopted Accounting Pronouncements In August 2018, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2018-15, Intangibles—Goodwill and Other (Topic 350): Internal-Use Software (“ASU 2018-15”). ASU 2018-15 aligns the requirements for capitalizing implementation costs incurred in a cloud computing arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software. We adopted ASU 2018-15 in the first quarter of our fiscal 2021 and the adoption did not have a significant impact on our condensed consolidated financial statements. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments and subsequent amendments to the initial guidance: ASU 2018-19, ASU 2019-04, ASU 2019-05 and ASU 2019-11 (collectively, “Topic 326”). Topic 326 requires measurement and recognition of expected credit losses for financial assets held. We adopted Topic 326 in the first quarter of our fiscal 2021 and the adoption did not have a significant impact on our condensed consolidated financial statements. Recent Accounting Pronouncements Not Yet Adopted We do not expect that any recently issued accounting pronouncements will have a significant effect on our financial statements.