Unaudited Interim Information	9 Months Ended
Jun. 30, 2016
Accounting Policies [Abstract]
Unaudited Interim Information	UNAUDITED INTERIM INFORMATION The accompanying unaudited condensed consolidated financial statements of Atwood Oceanics, Inc. and its subsidiaries as of June 30, 2016 and for the three and nine months ended June 30, 2016 and 2015, have been prepared in accordance with accounting principles generally accepted in the United States for interim financial information. Unless otherwise indicated, references to “we”, “us”, “our” and the “Company” refer collectively to Atwood Oceanics, Inc. and subsidiaries. The year-end condensed consolidated balance sheet data was derived from the audited financial statements as of September 30, 2015. Although these financial statements and related information have been prepared without audit and certain information and note disclosures normally included in financial statements prepared in accordance with generally accepted accounting principles have been condensed or omitted, we believe that the note disclosures are adequate to make the information not misleading. The interim financial results may not be indicative of results that could be expected for a full fiscal year. These unaudited condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and the related notes included in our Annual Report on Form 10-K for the year ended September 30, 2015. In our opinion, the unaudited interim financial statements reflect all adjustments considered necessary for a fair statement of our financial position, results of operations, changes in shareholders' equity, and cash flows for the periods presented. Certain prior period amounts have been reclassified to conform to current year presentation. Recently issued accounting pronouncements In June, 2016, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update (ASU) 2016-13, Financial Instruments – Credit Losses (Topic 326). The ASU introduces a new model for recognizing credit losses on financial instruments based on an estimate of current expected credit losses. The new model will apply to: (1) loans, accounts receivable, trade receivables, and other financial assets measured at amortized cost, (2) loan commitments and certain other off-balance sheet credit exposures, (3) debt securities and other financial assets measured at fair value through other comprehensive income, and (4) beneficial interests in securitized financial assets. This update is effective for annual and interim periods beginning after December 15, 2019. We are currently evaluating what impact the adoption of this guidance will have on our financial statements or disclosures in our financial statements. In March 2016, the FASB issued ASU 2016-09, Improvements to Employee Share-Based Payment Accounting, as part of its simplification initiative. The ASU simplifies several aspects of the accounting for employee share-based payment transactions, including the accounting for income taxes, classification of excess tax benefits on the statement of cash flows, forfeitures, statutory tax withholding requirements, classification of awards as either equity or liabilities, and classification of employee taxes paid on the statement of cash flows when an employer withholds shares for tax-withholding purposes. The amendments in this update are effective for annual periods beginning after December 15, 2016, and interim periods within those annual periods. We are currently evaluating what impact the adoption of this guidance will have on our financial statements or disclosures in our financial statements. In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842): Amendments to the FASB Accounting Standards Codification ("Update 2016-02"), which requires an entity to recognize lease assets and lease liabilities on the balance sheet and to disclose key qualitative and quantitative information about the entity's leasing arrangements. This update is effective for annual and interim periods beginning after December 15, 2018, with early adoption permitted. A modified retrospective approach is required. We are currently evaluating what impact the adoption of this guidance will have on our financial statements or disclosures in our financial statements. In November 2015, amended guidance from the FASB was issued for the balance sheet classification of deferred income taxes. The amended guidance requires the classification of all deferred tax assets and liabilities as noncurrent on the balance sheet instead of separating deferred taxes into current and noncurrent amounts. Deferred tax assets and liabilities will continue to be offset and presented as a single amount under the amended guidance. The effective date for public business entities is for financial statements issued for annual periods beginning after December 15, 2016, and interim periods within those annual periods. We have not yet adopted nor selected a transition method and are currently evaluating what impact the adoption of this guidance will have on our financial statements or disclosures in our financial statements. In April 2015, the FASB issued new guidance intended to simplify the presentation of debt issuance costs. This new guidance requires that debt issuance costs related to outstanding debt be netted against that liability in the balance sheet, consistent with the treatment of debt discounts. In August 2015, the FASB issued additional guidance to clarify that this presentation change does not address debt issuance costs related to line of credit arrangements. The new presentation guidance is effective for fiscal years and interim periods beginning after December 15, 2015 and early adoption is permitted. We adopted this guidance in the first quarter of fiscal 2016. We reclassified $1.7 million from Prepaid Expenses, Deferred Costs and Other Current Assets and $6.0 million from Deferred Costs and Other Assets to Long-Term Debt in the September 30, 2015 Condensed Consolidated Balance Sheet presented in this Form 10-Q to conform to the current year presentation of debt issuance costs. In May 2014, the FASB issued new guidance intended to change the criteria for recognition of revenue. The core principle of the guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The guidance is effective for annual reporting periods beginning after December 15, 2017, including interim periods within that reporting period. We are currently evaluating what impact the adoption of this guidance will have on our financial statements or disclosures in our financial statements.

UNAUDITED INTERIM INFORMATION

The accompanying unaudited condensed consolidated financial statements of Atwood Oceanics, Inc. and its subsidiaries as of June 30, 2016 and for the three and nine months ended June 30, 2016 and 2015, have been prepared in accordance with accounting principles generally accepted in the United States for interim financial information. Unless otherwise indicated, references to “we”, “us”, “our” and the “Company” refer collectively to Atwood Oceanics, Inc. and subsidiaries. The year-end condensed consolidated balance sheet data was derived from the audited financial statements as of September 30, 2015. Although these financial statements and related information have been prepared without audit and certain information and note disclosures normally included in financial statements prepared in accordance with generally accepted accounting principles have been condensed or omitted, we believe that the note disclosures are adequate to make the information not misleading. The interim financial results may not be indicative of results that could be expected for a full fiscal year. These unaudited condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and the related notes included in our Annual Report on Form 10-K for the year ended September 30, 2015. In our opinion, the unaudited interim financial statements reflect all adjustments considered necessary for a fair statement of our financial position, results of operations, changes in shareholders' equity, and cash flows for the periods presented. Certain prior period amounts have been reclassified to conform to current year presentation.

Recently issued accounting pronouncements

In June, 2016, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update (ASU) 2016-13, Financial Instruments – Credit Losses (Topic 326). The ASU introduces a new model for recognizing credit losses on financial instruments based on an estimate of current expected credit losses. The new model will apply to: (1) loans, accounts receivable, trade receivables, and other financial assets measured at amortized cost, (2) loan commitments and certain other off-balance sheet credit exposures, (3) debt securities and other financial assets measured at fair value through other comprehensive income, and (4) beneficial interests in securitized financial assets. This update is effective for annual and interim periods beginning after December 15, 2019. We are currently evaluating what impact the adoption of this guidance will have on our financial statements or disclosures in our financial statements.

In March 2016, the FASB issued ASU 2016-09, Improvements to Employee Share-Based Payment Accounting, as part of its simplification initiative. The ASU simplifies several aspects of the accounting for employee share-based payment transactions, including the accounting for income taxes, classification of excess tax benefits on the statement of cash flows, forfeitures, statutory tax withholding requirements, classification of awards as either equity or liabilities, and classification of employee taxes paid on the statement of cash flows when an employer withholds shares for tax-withholding purposes. The amendments in this update are effective for annual periods beginning after December 15, 2016, and interim periods within those annual periods. We are currently evaluating what impact the adoption of this guidance will have on our financial statements or disclosures in our financial statements.

In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842): Amendments to the FASB Accounting Standards Codification ("Update 2016-02"), which requires an entity to recognize lease assets and lease liabilities on the balance sheet and to disclose key qualitative and quantitative information about the entity's leasing arrangements. This update is effective for annual and interim periods beginning after December 15, 2018, with early adoption permitted. A modified retrospective approach is required. We are currently evaluating what impact the adoption of this guidance will have on our financial statements or disclosures in our financial statements.

In November 2015, amended guidance from the FASB was issued for the balance sheet classification of deferred income taxes. The amended guidance requires the classification of all deferred tax assets and liabilities as noncurrent on the balance sheet instead of separating deferred taxes into current and noncurrent amounts. Deferred tax assets and liabilities will continue to be offset and presented as a single amount under the amended guidance. The effective date for public business entities is for financial statements issued for annual periods beginning after December 15, 2016, and interim periods within those annual periods. We have not yet adopted nor selected a transition method and are currently evaluating what impact the adoption of this guidance will have on our financial statements or disclosures in our financial statements.

In April 2015, the FASB issued new guidance intended to simplify the presentation of debt issuance costs. This new guidance requires that debt issuance costs related to outstanding debt be netted against that liability in the balance sheet, consistent with the treatment of debt discounts. In August 2015, the FASB issued additional guidance to clarify that this presentation change does not address debt issuance costs related to line of credit arrangements. The new presentation guidance is effective for fiscal years and interim periods beginning after December 15, 2015 and early adoption is permitted. We adopted this guidance in the first quarter of fiscal 2016. We reclassified $1.7 million from Prepaid Expenses, Deferred Costs and Other Current Assets and $6.0 million from Deferred Costs and Other Assets to Long-Term Debt in the September 30, 2015 Condensed Consolidated Balance Sheet presented in this Form 10-Q to conform to the current year presentation of debt issuance costs.

In May 2014, the FASB issued new guidance intended to change the criteria for recognition of revenue. The core principle of the guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The guidance is effective for annual reporting periods beginning after December 15, 2017, including interim periods within that reporting period. We are currently evaluating what impact the adoption of this guidance will have on our financial statements or disclosures in our financial statements.