Management Contracts Purchased	6 Months Ended
Mar. 31, 2015
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. Prior to September 30, 2012, the Company had completed several purchases of assets related to the management of thirteen different mutual funds, some of which were reorganized into already existing Hennessy Funds. On October 26, 2012, the Company purchased the assets related to the management of the entire family of ten FBR funds (the “FBR Funds”), adding approximately $2.2 billion in assets under management. The purchase was consummated in accordance with the terms and conditions of that certain Asset Purchase Agreement, dated as of June 6, 2012, between the Company and FBR Fund Advisers, Inc. The purchase price was comprised of two payments: (i) an initial payment of $19,692,137 made on October 26, 2012 based upon the net asset value of the FBR Funds as of October 25, 2012 and (ii) a contingent payment of $19,193,595 made on November 5, 2013 based upon the net asset value of the FBR Funds as of October 28, 2013. The initial payment was funded with $3.4 million of available cash and $16.3 million of debt proceeds that were obtained pursuant to an amendment and restatement of the Company’s then-existing loan agreement with U.S. Bank National Association that allowed the Company to borrow the additional amount due. The contingent payment due under the Asset Purchase Agreement was determined to be $19,193,595 as of October 28, 2013. The amount of the liability was booked as of September 30, 2013 because it was measurable. The contingent payment was funded in part with $13,286,666 of debt proceeds that were obtained pursuant to an amendment of the Company’s then-existing loan agreement with U.S. Bank National Association that allowed the Company to borrow such amount, with the remainder of the payment being funded out of available cash. 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 March 31, 2015, 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 March 31, 2015.

(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. Prior to September 30, 2012, the Company had completed several purchases of assets related to the management of thirteen different mutual funds, some of which were reorganized into already existing Hennessy Funds. On October 26, 2012, the Company purchased the assets related to the management of the entire family of ten FBR funds (the “FBR Funds”), adding approximately $2.2 billion in assets under management. The purchase was consummated in accordance with the terms and conditions of that certain Asset Purchase Agreement, dated as of June 6, 2012, between the Company and FBR Fund Advisers, Inc. The purchase price was comprised of two payments: (i) an initial payment of $19,692,137 made on October 26, 2012 based upon the net asset value of the FBR Funds as of October 25, 2012 and (ii) a contingent payment of $19,193,595 made on November 5, 2013 based upon the net asset value of the FBR Funds as of October 28, 2013. The initial payment was funded with $3.4 million of available cash and $16.3 million of debt proceeds that were obtained pursuant to an amendment and restatement of the Company’s then-existing loan agreement with U.S. Bank National Association that allowed the Company to borrow the additional amount due.

The contingent payment due under the Asset Purchase Agreement was determined to be $19,193,595 as of October 28, 2013. The amount of the liability was booked as of September 30, 2013 because it was measurable. The contingent payment was funded in part with $13,286,666 of debt proceeds that were obtained pursuant to an amendment of the Company’s then-existing loan agreement with U.S. Bank National Association that allowed the Company to borrow such amount, with the remainder of the payment being funded out of available cash.

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 March 31, 2015, 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 March 31, 2015.