Accounting Policies, by Policy (Policies)	3 Months Ended
Accounting Policies, by Policy (Policies)	Sep. 30, 2017
Accounting Policies [Abstract]
Basis of Accounting, Policy [Policy Text Block]	U.S. Global Investors, Inc. (the “Company” or “U.S. Global”) has prepared the consolidated financial statements pursuant to accounting principles generally accepted in the United States of America (“U.S. GAAP”) and the rules and regulations of the United States Securities and Exchange Commission (“SEC”) that permit reduced disclosure for interim periods. The financial information included herein reflects all adjustments (consisting solely of normal recurring adjustments), which are, in management’s opinion, necessary for a fair presentation of results for the interim periods presented. The Company has consistently followed the accounting policies set forth in the notes to the consolidated financial statements in the Company’s Form 10-K for the fiscal year ended June 30, 2017, except for the adoption of new accounting pronouncements discussed below. The consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries, U.S. Global Brokerage, Inc., U.S. Global Investors (Bermuda) Limited, U.S. Global Investors (Canada) Limited (“USCAN”), and U.S. Global Indices, LLC, and its 65 percent interest in Galileo Global Equity Advisor Inc. (“Galileo”). U.S. Global Brokerage, Inc. ceased operations in December 2015. Galileo is consolidated with the operations of the Company. The non-controlling interest in this subsidiary is included in “non-controlling interest in subsidiary” in the equity section of the Consolidated Balance Sheets. Frank Holmes, CEO, and Susan McGee, President and General Counsel, serve as directors of Galileo. There are two primary consolidation models in U.S. GAAP, the variable interest entity (“VIE”) and voting interest entity models. The Company’s evaluation for consolidation includes whether entities in which it has an interest or from which it receives fees are VIEs and whether the Company is the primary beneficiary of any VIEs identified in its analysis. A VIE is an entity in which either (a) the equity investment at risk is not sufficient to permit the entity to finance its own activities without additional financial support or (b) the group of holders of the equity investment at risk lack certain characteristics of a controlling financial interest. The primary beneficiary is the entity that has the obligation to absorb a majority of the expected losses or the right to receive the majority of the residual returns and consolidates the VIE on the basis of having a controlling financial interest. The Company holds variable interests in, but is not deemed to be the primary beneficiary of, certain funds it advises, specifically, certain funds in U.S. Global Investors Funds (“USGIF” or the “Funds”) and one of the offshore funds. The Company’s interests in these VIEs consist of the Company’s direct ownership therein and any fees earned but uncollected. See further information about these funds in Notes 2 and 3. In the ordinary course of business, the Company may choose to waive certain fees or assume operating expenses of the funds it advises for competitive, regulatory or contractual reasons (see Note 3 for information regarding fee waivers). The Company has not provided financial support to any of these entities outside the ordinary course of business. The Company’s risk of loss with respect to these VIEs is limited to the carrying value of its investments in, and fees receivable from, the entities. The Company does not consolidate these VIEs because it is not the primary beneficiary. The Company’s total exposure to unconsolidated VIEs, consisting of the carrying value of investment securities and receivables for fees, was $9.1 million at September 30, 2017, and $11.3 million at June 30, 2017. The Company holds a variable interest in a fund advised by Galileo, but this fund does not qualify as a VIE. Since the fund is not a VIE, the Company evaluated if it should consolidate the fund under the voting interest entity model. Under the voting interest model, for legal entities other than partnerships, the usual condition for control is ownership, directly or indirectly, of more than 50 percent of the outstanding voting shares over an entity. The Company does not have control of the fund and, therefore, does not consolidate the fund. However, the Company owns approximately 30 percent of the fund, and is considered to have the ability to exercise significant influence. Thus, the investment is accounted for under the equity method of accounting. See further information about this investment in Note 2. All significant intercompany balances and transactions have been eliminated in consolidation. Certain amounts have been reclassified for comparative purposes. The results of operations for the three months ended September 30, 2017, are not necessarily indicative of the results to be expected for the entire year. The unaudited interim financial information in these condensed financial statements should be read in conjunction with the consolidated financial statements contained in the Company’s annual report.
New Accounting Pronouncements, Policy [Policy Text Block]	Recent Accounting Pronouncements Accounting Pronouncements Adopted During the Period In March 2016, the FASB issued Accounting Standards Update (“ASU”) 2016-09, Improvements to Employee Share-Based Payment Accounting (“ASU 2016-09”). ASU 2016-09 includes provisions intended to simplify various aspects related to how share-based payments are accounted for and disclosed. ASU 2016-09 is effective for public business entities for annual reporting periods beginning after December 15, 2016, and interim periods within those annual periods. The Company adopted this guidance on July 1, 2017, without a material impact to the consolidated financial statements. Accounting Pronouncements Not Yet Adopted In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers (“ASU 2014-09”), which supersedes nearly all existing revenue recognition guidance under U.S. GAAP. The core principle of ASU 2014-09 is to recognize revenues when promised goods or services are transferred to customers in an amount that reflects the consideration to which an entity expects to be entitled for those goods or services. ASU 2014-09 defines a five-step process to achieve this core principle and, in doing so, more judgment and estimates may be required within the revenue recognition process than are required under existing U.S. GAAP. The standard is effective for annual periods beginning after December 15, 2017, and interim periods therein, using either of the following transition methods: (i) a full retrospective approach reflecting the application of the standard in each prior reporting period with the option to elect certain practical expedients, or (ii) a retrospective approach with the cumulative effect of initially adopting ASU 2014-09 recognized at the date of adoption (which includes additional footnote disclosures). Early adoption is permitted, but the Company currently does not expect to implement the new standard before the required effective date. Additional ASUs have been issued to clarify certain aspects of ASU 2014-09. ASU 2016-08, Principal versus Agent Considerations (Reporting Revenue Gross versus Net) amends ASU 2014-09 to clarify that an entity should evaluate whether it is the principal or the agent for each specified good or service promised in a contract with a customer. ASU 2016-10, Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing, clarifies the guidance related to identifying performance obligations and the licensing guidance in ASU 2014-09. ASU 2016-12, Narrow-Scope Improvements and Practical Expedients, and ASU 2016-20, Technical Corrections and Improvements in Topic 606 Revenue from Contracts with Customers, provide additional clarification to a number of topics addressed in ASU No. 2014-09. These ASUs are effective in conjunction with the adoption of ASU 2014-09. The Company expects to adopt the guidance in the first quarter of fiscal year 2019 on a modified retrospective basis. The Company is in the process of evaluating its contracts using the prescribed five-step process to determine the impact of this standard and does not currently expect the adoption to have a material impact on its consolidated financial statements. While the Company continues to evaluate the impact of the revenue recognition guidance and cannot currently quantify the impact of the guidance, the Company has begun a preliminary assessment of the impact. The assessment includes a detailed review of the investment management agreements, establishing which agreements are expected to be in place, and understanding when revenue would be recognized under those agreements. The Company anticipates completing its evaluation in the year ending June 30, 2018. In January 2016, the FASB issued ASU 2016-01, Recognition and Measurement of Financial Assets and Financial Liabilities (“ASU 2016-01”). ASU 2016-01 amends the guidance on the classification and measurement of investments in equity securities. It also amends certain presentation and disclosure requirements. Under the amended guidance, all equity investments in unconsolidated entities (other than those accounted for using the equity method of accounting) will generally be measured at fair value through earnings. There will no longer be an available-for-sale classification (changes in fair value reported in other comprehensive income) for equity securities with readily determinable fair values. ASU 2016-01 is effective for public business entities for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. As indicated, when this standard is adopted, changes in the fair value of the Company’s investments securities classified as available-for-sale will no longer be reported through other comprehensive income, but rather through earnings, causing investment income (loss) to be more volatile. As a significant amount of the Company’s assets are in available-for-sale investments, the effect of adoption is expected to be material to the Company’s consolidated financial statements. The Company is currently evaluating other potential impacts of this standard on its consolidated financial statements. In February 2016, the FASB issued ASU 2016-02, Leases (“ASU 2016-02”). ASU 2016-02 introduces a lessee model that brings most leases on the balance sheet by recording a lease asset and a lease liability. The new guidance will be effective for public business entities for annual periods beginning after December 15, 2018, and interim periods therein. Early adoption is permitted. The Company’s current leases are primarily for equipment and for office space for the Canadian subsidiary. The Company does not expect that adoption will have a material impact on its consolidated statements of operations because its leases are currently classified as operating leases, which under the guidance will continue to be recognized as expense on a straight-line basis. The adoption, however, will result in a gross up in total assets and total liabilities on the Company’s consolidated balance sheets. In June 2016, the FASB issued ASU 2016-13, Financial Instruments – Credit Losses (Topic 326), Measurement of Credit Losses on Financial Instruments (“ASU 2016-13”). ASU 2016-13 adds to U.S. GAAP an impairment model (known as the current expected credit loss model) that is based on expected losses rather than incurred losses. Under the new guidance, an entity recognizes as an allowance its estimate of expected credit losses. ASU 2016-13 is effective for public business entities that are SEC filers for fiscal years beginning after December 15, 2019, including interim periods within those years. Earlier application is permitted only for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. The Company is currently evaluating the potential impact of this standard on its consolidated financial statements. In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments (“ASU 2016-15”). ASU 2016-15 may change how an entity classifies certain cash receipts and cash payments on its statement of cash flows to reduce existing diversity in practice. The guidance will generally be applied retrospectively and is effective for public business entities for fiscal years beginning after December 15, 2017, and interim periods within those years. Early adoption is permitted, and the Company is in the process of determining whether the standard will be early adopted. The Company is currently evaluating the potential impact of this standard but does not currently expect the adoption to have a material impact on the consolidated statements of cash flows. In November 2016, the FASB issued ASU 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash (“ASU 2016-18”). Under ASU 2016-18, restricted cash and restricted cash equivalents will be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. ASU 2016-18 is effective for public business entities for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. The guidance will be applied retrospectively, and early adoption is permitted. The Company is in the process of determining whether the standard will be early adopted but does not currently expect the adoption to have a material impact on its consolidated financial statements.