Basis Of Presentation	6 Months Ended
Dec. 31, 2016
Basis Of Presentation [Abstract]
Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]	BASIS OF PRESENTATION The accompanying unaudited condensed consolidated financial statements of PAREXEL International Corporation (“PAREXEL,” the “Company,” “we,” “our” or “us”) have been prepared in accordance with generally accepted accounting principles ("GAAP") for interim financial information in the United States and the instructions of Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and notes required by generally accepted accounting principles for complete financial statements. In the opinion of management, all adjustments (primarily consisting of normal recurring adjustments) considered necessary for a fair presentation of the Company’s financial position as of December 31, 2016 and, results of operations for the three and six months ended December 31, 2016 and 2015 have been included. Operating results for the three and six months ended December 31, 2016 are not necessarily indicative of the results that may be expected for other quarters or the entire fiscal year. For further information, refer to the audited consolidated financial statements and footnotes thereto included in our Annual Report on Form 10-K for the fiscal year ended June 30, 2016 (the “2016 10-K”) filed with the Securities and Exchange Commission on September 9, 2016. In the three and six month periods ended December 31, 2016, we recorded $2.4 million and $8.3 million, respectively, of adjustments related to revenue arrangements recognized in prior periods. The adjustments were recorded as reductions to service revenues in the consolidated statements of income and comprehensive income for the three and six months ended December 31, 2016. We concluded that the effect of these errors was not material to our consolidated financial statements for the current period, or any of the prior periods and, as such, these consolidated financial statements are not materially misstated. Recently Issued Accounting Standards In May 2014, the FASB issued ASU No. 2014-09 (“ASU 2014-09”), Revenue from Contracts with Customers (Topic 606), which provides 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. To achieve this core principle, an entity should apply the following steps: (1) identify the contract(s) with a customer; (2) identify the performance obligations in the contract; (3) determine the transaction price; (4) allocate the transaction price to the performance obligations in the contract; and (5) recognize revenue when (or as) the entity satisfies a performance obligation. As originally issued, ASU 2014-09 will be effective prospectively for fiscal years and interim periods within those years beginning after December 15, 2016. On July 9, 2015, the FASB approved the proposal to defer the effective date of this standard by one year. Early adoption is permitted for annual periods beginning after December 16, 2016. The Company will adopt ASU 2014-09 effective July 1, 2018. We are assessing the impact of adopting ASU 2014-09 on our consolidated financial statements. Subsequent to issuing ASU 2014-09, the FASB issued the following amendments concerning clarification of ASU 2014-09. In March 2016, the FASB issued ASU No. 2016-08 (“ASU 2016-08”), Revenue from Contracts with Customers (Topic 606), Principal versus Agent Considerations (Reporting Revenue Gross versus Net), which further clarifies the implementation guidance on principal versus agent considerations. The new guidance requires either a retrospective or a modified retrospective approach to adoption. In April 2016, the FASB issued ASU No. 2016-10, (“ASU 2016-10”) Revenue from Contracts with Customers (Topic 606), Identifying Performance Obligations and Licensing, which clarifies the identification of performance obligations and the licensing implementation guidance, while retaining the related principles for those areas. In May 2016, the FASB issued ASU No. 2016-12 (“ASU 2016-12”), Revenue from Contracts with Customers (Topic 606): Narrow-Scope Improvements and Practical Expedients, which provides clarification on assessing the collectability criterion, presentation of sales taxes, measurement date for noncash consideration and completed contracts at transition. We are currently evaluating the impact these ASUs will have on our consolidated financial statements. In January 2016, the FASB issued ASU No. 2016-01 (“ASU 2016-01”), Financial Instruments—Overall (Subtopic 825-10)Recognition and Measurement of Financial Assets and Financial Liabilities. This ASU is intended to provide users of financial statements with more useful information on the recognition, measurement, presentation, and disclosure of financial instruments. ASU 2016-01 is effective for fiscal years beginning after December 15, 2017, with early adoption permitted. We are assessing the impact of adopting ASU No. 2016-01 on our consolidated financial statements. In February 2016, the FASB issued ASU No. 2016-02 (“ASU 2016-02”), Leases (Topic 842) Section A-Leases: Amendments to the FASB Accounting Standards Codification® Section B-Conforming Amendments Related to Leases: Amendments to the FASB Accounting Standards Codification® Section C-Background Information and Basis for Conclusions. This ASU requires an entity that leases assets to recognize on the balance sheet the assets and liabilities for the rights and obligations created by those leases. ASU 2016-02 is effective for fiscal years beginning after December 15, 2018, with early adoption permitted. We are assessing the impact of adopting ASU 2016-02 on our consolidated financial statements. In March 2016, the FASB issued ASU No. 2016-05 (“ASU 2016-05”), Derivatives and Hedging (Topic 815): Effect of Derivative Contract Novations on Existing Hedge Accounting Relationships (a Consensus of the Emerging Issues Task Force). This ASU clarifies that a change in the counterparty to a derivative instrument that has been designated as the hedging instrument under Topic 815 does not, in and of itself, require dedesignation of that hedging relationship provided that all other hedge accounting criteria continue to be met. ASU 2016-05 is effective for fiscal years beginning after December 15, 2016, with early adoption permitted. We are assessing the impact of adopting ASU 2016-05 on our consolidated financial statements. Recently Adopted Accounting Standards In the first quarter of our fiscal year ending June 30, 2017, the Company adopted ASU No. 2014-12 (“ASU 2014-12”), Accounting for Share-Based Payments When the Terms of an Award Provide That a Performance Target Could Be Achieved After the Requisite Service Period. ASU 2014-12 requires that a performance target that affects vesting and could be achieved after the requisite service period be treated as a performance condition. A reporting entity should apply existing guidance in Accounting Standards Codification (“ASC”) 718, Compensation—Stock Compensation, as it relates to such awards. ASU 2014-12 permits using either of two methods: (i) prospective to all awards granted or modified after the effective date; or (ii) retrospective to all awards with performance targets that are outstanding as of the beginning of the earliest annual period presented in the financial statements and to all new or modified awards thereafter, with the cumulative effect of applying ASU 2014-12 as an adjustment to the opening retained earnings balance as of the beginning of the earliest annual period presented in the financial statements. The adoption of this ASU did not have a material impact on our consolidated financial statements. In the first quarter of our fiscal year ending June 30, 2017, the Company adopted ASU No. 2015-16 (“ASU 2015-16”), Business Combinations (Topic 805): Simplifying the Accounting for Measurement-Period Adjustments. This ASU requires adjustments to provisional amounts that are identified during the measurement period of a business combination to be recognized in the reporting period in which the adjustment amounts are determined. Acquirers are no longer required to revise comparative information for prior periods as if the accounting for the business combination had been completed as of the acquisition date. The adoption of this ASU did not have a material impact on our consolidated financial statements. In the first quarter of our fiscal year ending June 30, 2017, the Company adopted ASU No. 2015-03 (“ASU 2015-03”), Simplifying the Presentation of Debt Issuance Costs. ASU 2015-03 requires the presentation of debt issue costs in the consolidated balance sheets as a reduction to the related debt liability rather than as an asset. Amortization of debt issuance costs continues to be classified as interest expense. The adoption of this ASU did not have a material impact on our consolidated financial statements. In the first quarter of our fiscal year ending June 30, 2017, the Company adopted ASU No. 2016-09 (“ASU 2016-09”), Compensation-Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting. This ASU simplifies the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. The following summarizes the effects of the adoption on the Company's unaudited condensed consolidated financial statements: Income taxes - Upon adoption of this standard, all excess tax benefits and tax deficiencies (including tax benefits of dividends on share-based payment awards) are recognized as income tax expense or benefit in the income statement. The tax effects of exercised or vested awards are treated as discrete items in the reporting period in which they occur. The Company also recognizes excess tax benefits regardless of whether the benefit reduces taxes payable in the current period. As a result, the Company recognized discrete adjustments to income tax expense for six months ended December 31, 2016, in the amount of $2.3 million related to excess tax benefits. The Company has applied the modified retrospective adoption approach beginning in Fiscal Year 2017. This cumulative-effect adjustment related to tax assets that had previously arisen from tax deductions for equity compensation expenses that were greater than the compensation recognized for financial reporting. These assets had been excluded from the deferred tax assets and liabilities totals on the balance sheet as a result of certain realization requirements previously included in ASC 718. Prior periods have not been adjusted. Forfeitures - Prior to adoption, share-based compensation expense was recognized on a straight line basis, net of estimated forfeitures, such that expense was recognized only for share-based awards that are expected to vest. A forfeiture rate was estimated annually and revised, if necessary, in subsequent periods if actual forfeitures differed from initial estimates. Upon adoption, the Company will no longer apply a forfeiture rate and instead will account for forfeitures as they occur. As we previously estimated forfeitures to determine stock-based compensation expense, this change resulted in a cumulative-effect adjustment as of July 1, 2016 to reduce retained earnings by $0.6 million. Statements of Cash Flows - The Company historically accounted for excess tax benefits on the Statement of Cash Flows as a financing activity. Upon adoption of this standard, excess tax benefits are classified as an operating activity. The Company has elected to adopt this portion of the standard on a prospective basis beginning in Fiscal Year 2017. Prior periods have not been adjusted. Earnings Per Share - The Company uses the treasury stock method to compute diluted earnings per share, unless the effect would be anti-dilutive. Under this method, the Company will no longer be required to estimate the tax rate and apply it to the dilutive share calculation for determining the dilutive earnings per share. The Company has applied this methodology beginning in Fiscal Year 2017, and prior periods have not been adjusted. Upon adoption, no other aspects of ASU 2016-09 had a material effect on the Company's unaudited condensed consolidated financial statements or related footnote disclosures.

BASIS OF PRESENTATION

The accompanying unaudited condensed consolidated financial statements of PAREXEL International Corporation (“PAREXEL,” the “Company,” “we,” “our” or “us”) have been prepared in accordance with generally accepted accounting principles ("GAAP") for interim financial information in the United States and the instructions of Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and notes required by generally accepted accounting principles for complete financial statements. In the opinion of management, all adjustments (primarily consisting of normal recurring adjustments) considered necessary for a fair presentation of the Company’s financial position as of December 31, 2016 and, results of operations for the three and six months ended December 31, 2016 and 2015 have been included. Operating results for the three and six months ended December 31, 2016 are not necessarily indicative of the results that may be expected for other quarters or the entire fiscal year. For further information, refer to the audited consolidated financial statements and footnotes thereto included in our Annual Report on Form 10-K for the fiscal year ended June 30, 2016 (the “2016 10-K”) filed with the Securities and Exchange Commission on September 9, 2016.

In the three and six month periods ended December 31, 2016, we recorded $2.4 million and $8.3 million, respectively, of adjustments related to revenue arrangements recognized in prior periods. The adjustments were recorded as reductions to service revenues in the consolidated statements of income and comprehensive income for the three and six months ended December 31, 2016. We concluded that the effect of these errors was not material to our consolidated financial statements for the current period, or any of the prior periods and, as such, these consolidated financial statements are not materially misstated.

Recently Issued Accounting Standards

In May 2014, the FASB issued ASU No. 2014-09 (“ASU 2014-09”), Revenue from Contracts with Customers (Topic 606), which provides 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. To achieve this core principle, an entity should apply the following steps: (1) identify the contract(s) with a customer; (2) identify the performance obligations in the contract; (3) determine the transaction price; (4) allocate the transaction price to the performance obligations in the contract; and (5) recognize revenue when (or as) the entity satisfies a performance obligation. As originally issued, ASU 2014-09 will be effective prospectively for fiscal years and interim periods within those years beginning after December 15, 2016. On July 9, 2015, the FASB approved the proposal to defer the effective date of this standard by one year. Early adoption is permitted for annual periods beginning after December 16, 2016. The Company will adopt ASU 2014-09 effective July 1, 2018. We are assessing the impact of adopting ASU 2014-09 on our consolidated financial statements.

Subsequent to issuing ASU 2014-09, the FASB issued the following amendments concerning clarification of ASU 2014-09. In March 2016, the FASB issued ASU No. 2016-08 (“ASU 2016-08”), Revenue from Contracts with Customers (Topic 606), Principal versus Agent Considerations (Reporting Revenue Gross versus Net), which further clarifies the implementation guidance on principal versus agent considerations. The new guidance requires either a retrospective or a modified retrospective approach to adoption. In April 2016, the FASB issued ASU No. 2016-10, (“ASU 2016-10”) Revenue from Contracts with Customers (Topic 606), Identifying Performance Obligations and Licensing, which clarifies the identification of performance obligations and the licensing implementation guidance, while retaining the related principles for those areas. In May 2016, the FASB issued ASU No. 2016-12 (“ASU 2016-12”), Revenue from Contracts with Customers (Topic 606): Narrow-Scope Improvements and Practical Expedients, which provides clarification on assessing the collectability criterion, presentation of sales taxes, measurement date for noncash consideration and completed contracts at transition. We are currently evaluating the impact these ASUs will have on our consolidated financial statements.

In January 2016, the FASB issued ASU No. 2016-01 (“ASU 2016-01”), Financial Instruments—Overall (Subtopic 825-10)Recognition and Measurement of Financial Assets and Financial Liabilities. This ASU is intended to provide users of financial statements with more useful information on the recognition, measurement, presentation, and disclosure of financial instruments. ASU 2016-01 is effective for fiscal years beginning after December 15, 2017, with early adoption permitted. We are assessing the impact of adopting ASU No. 2016-01 on our consolidated financial statements.

In February 2016, the FASB issued ASU No. 2016-02 (“ASU 2016-02”), Leases (Topic 842) Section A-Leases: Amendments to the FASB Accounting Standards Codification® Section B-Conforming Amendments Related to Leases: Amendments to the FASB Accounting Standards Codification® Section C-Background Information and Basis for Conclusions. This ASU requires an entity that leases assets to recognize on the balance sheet the assets and liabilities for the rights and obligations created by those leases. ASU 2016-02 is effective for fiscal years beginning after December 15, 2018, with early adoption permitted. We are assessing the impact of adopting ASU 2016-02 on our consolidated financial statements.

In March 2016, the FASB issued ASU No. 2016-05 (“ASU 2016-05”), Derivatives and Hedging (Topic 815): Effect of Derivative Contract Novations on Existing Hedge Accounting Relationships (a Consensus of the Emerging Issues Task Force). This ASU clarifies that a change in the counterparty to a derivative instrument that has been designated as the hedging instrument under Topic 815 does not, in and of itself, require dedesignation of that hedging relationship provided that all other hedge accounting criteria continue to be met. ASU 2016-05 is effective for fiscal years beginning after December 15, 2016, with early adoption permitted. We are assessing the impact of adopting ASU 2016-05 on our consolidated financial statements.

Recently Adopted Accounting Standards

In the first quarter of our fiscal year ending June 30, 2017, the Company adopted ASU No. 2014-12 (“ASU 2014-12”), Accounting for Share-Based Payments When the Terms of an Award Provide That a Performance Target Could Be Achieved After the Requisite Service Period. ASU 2014-12 requires that a performance target that affects vesting and could be achieved after the requisite service period be treated as a performance condition. A reporting entity should apply existing guidance in Accounting Standards Codification (“ASC”) 718, Compensation—Stock Compensation, as it relates to such awards. ASU 2014-12 permits using either of two methods: (i) prospective to all awards granted or modified after the effective date; or (ii) retrospective to all awards with performance targets that are outstanding as of the beginning of the earliest annual period presented in the financial statements and to all new or modified awards thereafter, with the cumulative effect of applying ASU 2014-12 as an adjustment to the opening retained earnings balance as of the beginning of the earliest annual period presented in the financial statements. The adoption of this ASU did not have a material impact on our consolidated financial statements.

In the first quarter of our fiscal year ending June 30, 2017, the Company adopted ASU No. 2015-16 (“ASU 2015-16”), Business Combinations (Topic 805): Simplifying the Accounting for Measurement-Period Adjustments. This ASU requires adjustments to provisional amounts that are identified during the measurement period of a business combination to be recognized in the reporting period in which the adjustment amounts are determined. Acquirers are no longer required to revise comparative information for prior periods as if the accounting for the business combination had been completed as of the acquisition date. The adoption of this ASU did not have a material impact on our consolidated financial statements.

In the first quarter of our fiscal year ending June 30, 2017, the Company adopted ASU No. 2015-03 (“ASU 2015-03”), Simplifying the Presentation of Debt Issuance Costs. ASU 2015-03 requires the presentation of debt issue costs in the consolidated balance sheets as a reduction to the related debt liability rather than as an asset. Amortization of debt issuance costs continues to be classified as interest expense. The adoption of this ASU did not have a material impact on our consolidated financial statements.

In the first quarter of our fiscal year ending June 30, 2017, the Company adopted ASU No. 2016-09 (“ASU 2016-09”), Compensation-Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting. This ASU simplifies the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. The following summarizes the effects of the adoption on the Company's unaudited condensed consolidated financial statements:

Income taxes - Upon adoption of this standard, all excess tax benefits and tax deficiencies (including tax benefits of dividends on share-based payment awards) are recognized as income tax expense or benefit in the income statement. The tax effects of exercised or vested awards are treated as discrete items in the reporting period in which they occur. The Company also recognizes excess tax benefits regardless of whether the benefit reduces taxes payable in the current period. As a result, the Company recognized discrete adjustments to income tax expense for six months ended December 31, 2016, in the amount of $2.3 million related to excess tax benefits. The Company has applied the modified retrospective adoption approach beginning in Fiscal Year 2017. This cumulative-effect adjustment related to tax assets that had previously arisen from tax deductions for equity compensation expenses that were greater than the compensation recognized for financial reporting. These assets had been excluded from the deferred tax assets and liabilities totals on the balance sheet as a result of certain realization requirements previously included in ASC 718. Prior periods have not been adjusted.

Forfeitures - Prior to adoption, share-based compensation expense was recognized on a straight line basis, net of estimated forfeitures, such that expense was recognized only for share-based awards that are expected to vest. A forfeiture rate was estimated annually and revised, if necessary, in subsequent periods if actual forfeitures differed from initial estimates. Upon adoption, the Company will no longer apply a forfeiture rate and instead will account for forfeitures as they occur. As we previously estimated forfeitures to determine stock-based compensation expense, this change resulted in a cumulative-effect adjustment as of July 1, 2016 to reduce retained earnings by $0.6 million.

Statements of Cash Flows - The Company historically accounted for excess tax benefits on the Statement of Cash Flows as a financing activity. Upon adoption of this standard, excess tax benefits are classified as an operating activity. The Company has elected to adopt this portion of the standard on a prospective basis beginning in Fiscal Year 2017. Prior periods have not been adjusted.

Earnings Per Share - The Company uses the treasury stock method to compute diluted earnings per share, unless the effect would be anti-dilutive. Under this method, the Company will no longer be required to estimate the tax rate and apply it to the dilutive share calculation for determining the dilutive earnings per share. The Company has applied this methodology beginning in Fiscal Year 2017, and prior periods have not been adjusted.

Upon adoption, no other aspects of ASU 2016-09 had a material effect on the Company's unaudited condensed consolidated financial statements or related footnote disclosures.