Nature of Operations and Accounting Policies (Policies)	9 Months Ended
Apr. 30, 2017
Accounting Policies [Abstract]
Nature of Operations	Nature of Operations Thor Industries, Inc. was founded in 1980 and, through its subsidiaries (collectively, the “Company”), manufactures a wide range of recreational vehicles (“RVs”) in the United States at various manufacturing facilities located primarily in Indiana and Ohio, with additional facilities in Oregon and Idaho. These products are sold to independent, non-franchise dealers primarily throughout the United States and Canada. Unless the context requires or indicates otherwise, all references to “Thor”, the “Company”, “we”, “our” and “us” refer to Thor Industries, Inc. and its subsidiaries. The July 31, 2016 amounts are derived from the annual audited financial statements. The interim financial statements are unaudited. In the opinion of management, all adjustments (which consist of normal recurring adjustments) necessary to present fairly the financial position, results of operations and cash flows for the interim periods presented have been made. These financial statements should be read in conjunction with the Company’s Annual Report on Form 10-K for the fiscal year ended July 31, 2016. Due to seasonality within the recreational vehicle industry, annualizing the results of operations for the nine months ended April 30, 2017 would not necessarily be indicative of the results for a full fiscal year.
Accounting Pronouncements	Accounting Pronouncements In January 2017, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update No. 2017-04, “Intangibles—Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment,” which eliminates the requirement to calculate the implied fair value of goodwill to measure a goodwill impairment charge (referred to as Step 2 in the goodwill impairment test). Instead, if the carrying amount of a reporting unit exceeds its fair value, an impairment charge equal to that excess shall be recognized, not to exceed the amount of goodwill allocated to the reporting unit. The standard is effective for annual and any interim impairment tests for periods beginning after December 15, 2019, with early adoption permitted after January 1, 2017. The standard is effective for the Company in its fiscal year 2021 beginning on August 1, 2020. The Company is currently evaluating the impact of this standard on its consolidated financial statements, which will depend on the outcomes of future goodwill impairment tests. In March 2016, the FASB issued Accounting Standards Update No. 2016-09 (“ASU 2016-09”) “Improvements to Employee Share-Based Payment Accounting,” which simplifies several aspects of the accounting for employee share-based payment transactions, including the accounting for the related income taxes, forfeitures, statutory tax withholding requirements and classification in the statement of cash flows. ASU 2016-09 is effective for annual reporting periods beginning after December 15, 2016, including interim periods within those annual reporting periods. Early adoption is permitted and the Company adopted the provisions of ASU 2016-09 as of August 1, 2016. Applicable provisions of the standard have been adopted prospectively as allowed under the standard. The provisions related to income taxes resulted in a tax benefit of $0 and $1,843 for the three and nine months ended April 30, 2017, respectively. The Company did not change its policy related to forfeitures, which is estimated based on historical forfeiture rates over the vesting period of employee awards. Provisions related to the statement of cash flows have been adopted prospectively and result in the recognition of the excess tax benefits from share-based awards being reflected in cash provided by operating activities. In September 2015, the FASB issued Accounting Standards Update No. 2015-16 (“ASU 2015-16”) “Business Combinations (Topic 805): Simplifying the Accounting for Measurement-Period Adjustments,” to simplify the accounting for measurement-period adjustments in a business combination. Under the new standard, an acquirer must recognize adjustments to provisional amounts in a business combination in the reporting period in which the adjustment amounts are determined, rather than retrospectively adjusting the provisional amounts recognized at the acquisition date with a corresponding adjustment to goodwill as under current guidance. ASU 2015-16 is effective for fiscal years, and the interim periods within those years, beginning after December 15, 2015. The Company adopted ASU 2015-16 on August 1, 2016 and there was no impact upon adoption of this standard. In July 2015, the FASB issued Accounting Standards Update No. 2015-11 (“ASU 2015-11”) “Inventory (Topic 330): Simplifying the Measurement of Inventory.” ASU 2015-11 requires inventory measured using any method other than last-in, first-out (“LIFO”) or the retail inventory method to be subsequently measured at the lower of cost or net realizable value, rather than at the lower of cost or market. Under this ASU, subsequent measurement of inventory using the LIFO and retail inventory method is unchanged. ASU 2015-11 is effective prospectively for fiscal years, and for interim periods within those years, beginning after December 15, 2016. The standard is effective for the Company in its fiscal year 2018 beginning on August 1, 2017. Early adoption is permitted. The Company is currently evaluating the impact of this ASU on its consolidated financial statements. In May 2014, the FASB issued Accounting Standards Update No. 2014-09 “Revenue from Contracts with Customers (Topic 606),” which outlines a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers. This standard will supersede most current revenue recognition guidance. Under the new standard, entities are required to identify the contract with a customer, identify the separate performance obligations in the contract, determine the transaction price, allocate the transaction price to the separate performance obligations in the contract and recognize the appropriate amount of revenue when (or as) the entity satisfies each performance obligation. The standard is effective for fiscal years, and the interim periods within those years, beginning after December 15, 2017. The standard is effective for the Company in its fiscal year 2019 beginning on August 1, 2018. Entities have the option of using either retrospective transition or a modified approach in applying the new standard. The Company is currently evaluating the approach it will use to apply the new standard and the impact that the adoption of the new standard will have on the Company’s consolidated financial statements.

Accounting Pronouncements

In January 2017, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update No. 2017-04, “Intangibles—Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment,” which eliminates the requirement to calculate the implied fair value of goodwill to measure a goodwill impairment charge (referred to as Step 2 in the goodwill impairment test). Instead, if the carrying amount of a reporting unit exceeds its fair value, an impairment charge equal to that excess shall be recognized, not to exceed the amount of goodwill allocated to the reporting unit. The standard is effective for annual and any interim impairment tests for periods beginning after December 15, 2019, with early adoption permitted after January 1, 2017. The standard is effective for the Company in its fiscal year 2021 beginning on August 1, 2020. The Company is currently evaluating the impact of this standard on its consolidated financial statements, which will depend on the outcomes of future goodwill impairment tests.

In March 2016, the FASB issued Accounting Standards Update No. 2016-09 (“ASU 2016-09”) “Improvements to Employee Share-Based Payment Accounting,” which simplifies several aspects of the accounting for employee share-based payment transactions, including the accounting for the related income taxes, forfeitures, statutory tax withholding requirements and classification in the statement of cash flows. ASU 2016-09 is effective for annual reporting periods beginning after December 15, 2016, including interim periods within those annual reporting periods. Early adoption is permitted and the Company adopted the provisions of ASU 2016-09 as of August 1, 2016. Applicable provisions of the standard have been adopted prospectively as allowed under the standard. The provisions related to income taxes resulted in a tax benefit of $0 and $1,843 for the three and nine months ended April 30, 2017, respectively. The Company did not change its policy related to forfeitures, which is estimated based on historical forfeiture rates over the vesting period of employee awards. Provisions related to the statement of cash flows have been adopted prospectively and result in the recognition of the excess tax benefits from share-based awards being reflected in cash provided by operating activities.

In September 2015, the FASB issued Accounting Standards Update No. 2015-16 (“ASU 2015-16”) “Business Combinations (Topic 805): Simplifying the Accounting for Measurement-Period Adjustments,” to simplify the accounting for measurement-period adjustments in a business combination. Under the new standard, an acquirer must recognize adjustments to provisional amounts in a business combination in the reporting period in which the adjustment amounts are determined, rather than retrospectively adjusting the provisional amounts recognized at the acquisition date with a corresponding adjustment to goodwill as under current guidance. ASU 2015-16 is effective for fiscal years, and the interim periods within those years, beginning after December 15, 2015. The Company adopted ASU 2015-16 on August 1, 2016 and there was no impact upon adoption of this standard.

In July 2015, the FASB issued Accounting Standards Update No. 2015-11 (“ASU 2015-11”) “Inventory (Topic 330): Simplifying the Measurement of Inventory.” ASU 2015-11 requires inventory measured using any method other than last-in, first-out (“LIFO”) or the retail inventory method to be subsequently measured at the lower of cost or net realizable value, rather than at the lower of cost or market. Under this ASU, subsequent measurement of inventory using the LIFO and retail inventory method is unchanged. ASU 2015-11 is effective prospectively for fiscal years, and for interim periods within those years, beginning after December 15, 2016. The standard is effective for the Company in its fiscal year 2018 beginning on August 1, 2017. Early adoption is permitted. The Company is currently evaluating the impact of this ASU on its consolidated financial statements.

In May 2014, the FASB issued Accounting Standards Update No. 2014-09 “Revenue from Contracts with Customers (Topic 606),” which outlines a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers. This standard will supersede most current revenue recognition guidance. Under the new standard, entities are required to identify the contract with a customer, identify the separate performance obligations in the contract, determine the transaction price, allocate the transaction price to the separate performance obligations in the contract and recognize the appropriate amount of revenue when (or as) the entity satisfies each performance obligation. The standard is effective for fiscal years, and the interim periods within those years, beginning after December 15, 2017. The standard is effective for the Company in its fiscal year 2019 beginning on August 1, 2018. Entities have the option of using either retrospective transition or a modified approach in applying the new standard. The Company is currently evaluating the approach it will use to apply the new standard and the impact that the adoption of the new standard will have on the Company’s consolidated financial statements.