Management Contracts Purchased	9 Months Ended
Jun. 30, 2016
Text Block [Abstract]
Management Contracts Purchased	(2) Management Contracts Purchased The Company has purchased assets related to the management of open-end mutual funds from time to time throughout its history. As of June 30, 2016, the Company has completed several purchases of assets related to the management of 23 different mutual funds, some of which were reorganized into already existing Hennessy Funds. In accordance with guidance issued by the Financial Accounting Standards Board (“FASB”), the Company periodically reviews the carrying value of its purchased management contracts to determine if any impairment has occurred. The fair value of management contracts are based on management estimates and assumptions, including third-party valuations that utilize appropriate valuation techniques. The fair value of the management contracts was estimated by applying the income approach. As of June 30, 2016, no events or changes in circumstances had occurred that indicated potential impairment of the management contracts. Under the FASB guidance on “Intangibles – Goodwill and Other,” intangible assets that have indefinite useful lives are not amortized but are tested at least annually for impairment. The Company reviews the life of the management contracts each reporting period to determine if they continue to have an indefinite useful life. The Company considers the mutual fund management contracts to be intangible assets with an indefinite useful life as of June 30, 2016.

(2) Management Contracts Purchased

The Company has purchased assets related to the management of open-end mutual funds from time to time throughout its history. As of June 30, 2016, the Company has completed several purchases of assets related to the management of 23 different mutual funds, some of which were reorganized into already existing Hennessy Funds. In accordance with guidance issued by the Financial Accounting Standards Board (“FASB”), the Company periodically reviews the carrying value of its purchased management contracts to determine if any impairment has occurred. The fair value of management contracts are based on management estimates and assumptions, including third-party valuations that utilize appropriate valuation techniques. The fair value of the management contracts was estimated by applying the income approach. As of June 30, 2016, no events or changes in circumstances had occurred that indicated potential impairment of the management contracts.

Under the FASB guidance on “Intangibles – Goodwill and Other,” intangible assets that have indefinite useful lives are not amortized but are tested at least annually for impairment. The Company reviews the life of the management contracts each reporting period to determine if they continue to have an indefinite useful life. The Company considers the mutual fund management contracts to be intangible assets with an indefinite useful life as of June 30, 2016.