Business and Basis of Presentation (Policies)	6 Months Ended
Mar. 31, 2019
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation These consolidated financial statements have been prepared by the Company in accordance with accounting principles generally accepted in the United States of America (“GAAP”) for interim reporting and are unaudited. In the opinion of management, the accompanying unaudited consolidated financial statements include all adjustments, including normal, recurring accruals that are necessary for a fair presentation of the Company’s operations for the periods presented in conformity with GAAP. All intercompany activity and balances have been eliminated from the consolidated financial statements. The consolidated results of operations for the interim periods presented are not necessarily indicative of results for the full year. The consolidated balance sheet as of September 30, 2018, presented herein, has been derived from the Company’s audited consolidated financial statements as of and for the fiscal year ended September 30, 2018, but does not include all disclosures required by GAAP, for annual financial statements. For a more complete discussion of the Company’s accounting policies and certain other information refer to the audited consolidated financial statements and the notes thereto included in the Company’s annual report on Form 10-K for the fiscal year ended September 30, 2018, filed with the Securities and Exchange Commission (“SEC”).
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the period. On an ongoing basis, management reviews its estimates, including those related to allowances for doubtful accounts, revenue recognition, self-insurance reserves, estimates related to the Company’s assessment of goodwill for impairment, useful lives for depreciation and amortization, realizability of deferred tax assets, and litigation based on currently available information. Changes in facts and circumstances may result in revised estimates and actual results may differ from estimates.
Initial Public Offering	Initial Public Offering On July 2, 2018, the Company completed the IPO in which the Company issued and sold 24,495 shares of common stock. The shares sold in the offering were registered under the Securities Act pursuant to the Company’s Registration Statement on Form S-1 (File No. 333-225277) (the “Registration Statement”), which was declared effective by the SEC on June 27, 2018. The shares of the Company’s common stock were sold at an initial offering price of $22.00 per share, which generated net proceeds of approximately $501,172 to the Company, after deducting underwriting discounts and estimated offering expenses of approximately $37,717, which included $5,497 paid to KKR Capital Markets LLC (“KCM”), an affiliate of KKR, for underwriting services in connection with the IPO. The Company used the net proceeds from the IPO to repay all $110,000 of the Company’s second lien term loans, all $55,000 outstanding under the Company’s Revolving Credit Facility (as defined below) and approximately $336,100 of the Company’s first lien term loans and accrued and unpaid interest thereon. These repayments resulted in an extinguishment of debt in the amount of approximately $501,100, which was recognized in the fourth quarter of fiscal 2018. BrightView was party to a Monitoring Agreement, dated as of December 18, 2013 (the “Monitoring Agreement”), with KKR and MSD Partners (“MSD” and together with KKR, the “Sponsors”), which was terminated on July 2, 2018 in accordance with its terms upon the completion of the IPO. In connection with such termination, during the fourth quarter of fiscal 2018, the Company paid termination fees of approximately $7,598 and $3,438 to KKR and MSD, respectively. Affiliates of KKR and MSD retained 55.9% and 13.0% ownership interest, respectively, in the Company immediately after the IPO. The Company’s Third Amended and Restated Certificate of Incorporation (the “Charter”) became effective in connection with the completion of the IPO on July 2, 2018. The Charter, among other things, provides that the Company’s authorized capital stock consists of 500,000 shares of common stock, and 50,000 shares of preferred stock, par value $0.01 per share. The Company’s bylaws were also amended and restated as of July 2, 2018.
Stock Split	Stock Split In connection with preparing for the IPO, the Company’s Board of Directors approved a 2.33839-for-one reverse stock split of the Company’s common stock. The reverse stock split became effective June 8, 2018. The par value per share of common stock and authorized shares of common stock remain unchanged. The accompanying consolidated financial statements and notes thereto give retroactive effect to the reverse stock split for all periods presented.

Business and Basis of Presentation (Policies)

6 Months Ended

Mar. 31, 2019

These consolidated financial statements have been prepared by the Company in accordance with accounting principles generally accepted in the United States of America (“GAAP”) for interim reporting and are unaudited.

In the opinion of management, the accompanying unaudited consolidated financial statements include all adjustments, including normal, recurring accruals that are necessary for a fair presentation of the Company’s operations for the periods presented in conformity with GAAP. All intercompany activity and balances have been eliminated from the consolidated financial statements. The consolidated results of operations for the interim periods presented are not necessarily indicative of results for the full year.

The consolidated balance sheet as of September 30, 2018, presented herein, has been derived from the Company’s audited consolidated financial statements as of and for the fiscal year ended September 30, 2018, but does not include all disclosures required by GAAP, for annual financial statements. For a more complete discussion of the Company’s accounting policies and certain other information refer to the audited consolidated financial statements and the notes thereto included in the Company’s annual report on Form 10-K for the fiscal year ended September 30, 2018, filed with the Securities and Exchange Commission (“SEC”).

Use of Estimates

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the period. On an ongoing basis, management reviews its estimates, including those related to allowances for doubtful accounts, revenue recognition, self-insurance reserves, estimates related to the Company’s assessment of goodwill for impairment, useful lives for depreciation and amortization, realizability of deferred tax assets, and litigation based on currently available information. Changes in facts and circumstances may result in revised estimates and actual results may differ from estimates.

Initial Public Offering

On July 2, 2018, the Company completed the IPO in which the Company issued and sold 24,495 shares of common stock. The shares sold in the offering were registered under the Securities Act pursuant to the Company’s Registration Statement on Form S-1 (File No. 333-225277) (the “Registration Statement”), which was declared effective by the SEC on June 27, 2018. The shares of the Company’s common stock were sold at an initial offering price of $22.00 per share, which generated net proceeds of approximately $501,172 to the Company, after deducting underwriting discounts and estimated offering expenses of approximately $37,717, which included $5,497 paid to KKR Capital Markets LLC (“KCM”), an affiliate of KKR, for underwriting services in connection with the IPO. The Company used the net proceeds from the IPO to repay all $110,000 of the Company’s second lien term loans, all $55,000 outstanding under the Company’s Revolving Credit Facility (as defined below) and approximately $336,100 of the Company’s first lien term loans and accrued and unpaid interest thereon. These repayments resulted in an extinguishment of debt in the amount of approximately $501,100, which was recognized in the fourth quarter of fiscal 2018.

BrightView was party to a Monitoring Agreement, dated as of December 18, 2013 (the “Monitoring Agreement”), with KKR and MSD Partners (“MSD” and together with KKR, the “Sponsors”), which was terminated on July 2, 2018 in accordance with its terms upon the completion of the IPO. In connection with such termination, during the fourth quarter of fiscal 2018, the Company paid termination fees of approximately $7,598 and $3,438 to KKR and MSD, respectively. Affiliates of KKR and MSD retained 55.9% and 13.0% ownership interest, respectively, in the Company immediately after the IPO.

The Company’s Third Amended and Restated Certificate of Incorporation (the “Charter”) became effective in connection with the completion of the IPO on July 2, 2018. The Charter, among other things, provides that the Company’s authorized capital stock consists of 500,000 shares of common stock, and 50,000 shares of preferred stock, par value $0.01 per share. The Company’s bylaws were also amended and restated as of July 2, 2018.

Stock Split

In connection with preparing for the IPO, the Company’s Board of Directors approved a 2.33839-for-one reverse stock split of the Company’s common stock. The reverse stock split became effective June 8, 2018. The par value per share of common stock and authorized shares of common stock remain unchanged. The accompanying consolidated financial statements and notes thereto give retroactive effect to the reverse stock split for all periods presented.