Beacon Roofing Supply (BECN) 10-K 26 Nov 19 2019 FY Annual report Financial data

Document And Entity Information

Document And Entity Information - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2019	Oct. 31, 2019	Mar. 31, 2019
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Sep. 30, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Trading Symbol	BECN
Entity Registrant Name	BEACON ROOFING SUPPLY INC
Entity Central Index Key	0001124941
Current Fiscal Year End Date	--09-30
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 2,000
Entity Common Stock, Shares Outstanding		68,585,920
Title of 12(b) Security	Common Stock, $0.01 par value
Security Exchange Name	NASDAQ
Entity File Number	000-50924
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	36-4173371
Entity Address, Address Line One	505 Huntmar Park Drive
Entity Address, Address Line Two	Suite 300
Entity Address, City or Town	Herndon
Entity Address, State or Province	VA
Entity Address, Postal Zip Code	20170
City Area Code	571
Local Phone Number	323-3939
Document Annual Report	true
Document Transition Report	false
Documents Incorporated by Reference	The information required by Part III (Items 10, 11, 12, 13 and 14) will be incorporated by reference from the Registrant’s definitive proxy statement, which will be filed pursuant to Regulation 14A with the United States Securities and Exchange Commission (“SEC”) within 120 days after the end of the fiscal year to which this report relates.

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2019	Sep. 30, 2018
Current assets:
Cash and cash equivalents	$ 72,287	$ 129,927
Accounts receivable, less allowance of $13,095 and $17,584 as of September 30, 2019 and 2018, respectively	1,108,134	1,090,533
Inventories, net	1,018,183	936,047
Prepaid expenses and other current assets	315,643	244,360
Total current assets	2,514,247	2,400,867
Property and equipment, net	260,376	280,407
Goodwill	2,490,590	2,491,779
Intangibles, net	1,125,540	1,334,366
Other assets, net	2,059	1,243
Total assets	6,392,812	6,508,662
Current liabilities:
Accounts payable	822,931	880,872
Accrued expenses	599,155	611,539
Current portions of long-term debt/obligations	18,689	19,661
Total current liabilities	1,440,775	1,512,072
Borrowings under revolving lines of credit, net	80,961	92,442
Long-term debt, net	2,494,623	2,494,725
Deferred income taxes, net	103,913	106,994
Long-term obligations under equipment financing and other, net	4,609	13,639
Other long-term liabilities	6,383	5,290
Total liabilities	4,131,264	4,225,162
Commitments and contingencies (Note 9)
Convertible preferred stock; $0.01 par value; aggregate liquidation preference $400,000; 400,000 shares authorized, issued and outstanding as of September 30, 2019 and 2018	399,195	399,195
Stockholders' equity:
Common stock (voting); $0.01 par value; 100,000,000 shares authorized; 68,574,176 and 68,135,790 shares issued and outstanding as of September 30, 2019 and 2018, respectively	685	681
Undesignated preferred stock; 5,000,000 shares authorized, none issued or outstanding	0	0
Additional paid-in capital	1,083,042	1,067,040
Retained earnings	799,222	833,834
Accumulated other comprehensive income (loss)	(20,596)	(17,250)
Total stockholders' equity	1,862,353	1,884,305
Total liabilities and stockholders' equity	$ 6,392,812	$ 6,508,662

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2019	Sep. 30, 2018
Statement Of Financial Position [Abstract]
Accounts receivable, allowances	$ 13,095	$ 17,584
Convertible preferred stock, par value	$ 0.01	$ 0.01
Convertible preferred stock. aggregate liquidation preference	$ 400,000	$ 400,000
Convertible preferred stock, shares authorized	400,000	400,000
Convertible preferred stock, shares issued	400,000	400,000
Convertible preferred stock, shares outstanding	400,000	400,000
Common stock (voting), par value	$ 0.01	$ 0.01
Common stock (voting), shares authorized	100,000,000	100,000,000
Common Stock (voting), issued	68,574,176	68,135,790
Common Stock (voting), outstanding	68,574,176	68,135,790
Undesignated Preferred Stock, shares authorized	5,000,000	5,000,000
Undesignated Preferred Stock, issued	0	0
Undesignated Preferred Stock, outstanding	0	0

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands		12 Months Ended
		Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Income Statement [Abstract]
Net sales		$ 7,105,160	$ 6,418,311	$ 4,376,670
Cost of products sold		5,368,605	4,824,990	3,300,731
Gross profit		1,736,555	1,593,321	1,075,939
Operating expense:
Selling, general and administrative		1,311,043	1,187,192	743,376
Depreciation		70,695	60,318	34,002
Amortization		207,065	141,185	82,465
Total operating expense		1,588,803	1,388,695	859,843
Income (loss) from operations		147,752	204,626	216,096
Interest expense, financing costs, and other		158,534	136,544	52,751
Income (loss) before provision for income taxes		(10,782)	68,082	163,345
Provision for (benefit from) income taxes	[1]	(170)	(30,544)	62,481
Net income (loss)		(10,612)	98,626	100,864
Dividends on preferred shares	[2]	24,000	18,000	0
Net income (loss) attributable to common shareholders		$ (34,612)	$ 80,626	$ 100,864
Weighted-average common stock outstanding:
Basic		68,424,288	68,012,879	60,315,648
Diluted		68,424,288	69,191,039	61,344,263
Net income (loss) per share:
Basic	[3]	$ (0.51)	$ 1.07	$ 1.67
Diluted	[3]	$ (0.51)	$ 1.05	$ 1.64
[1]	Year ended September 30, 2018 amounts include a net tax benefit $49.2 million resulting from recording the provisional impact of the enactment of the 2017 Tax Cuts and Jobs Act (“TCJA”).
[2]	Year ended September 30, 2019 amount is composed of $5.0 million in undeclared cumulative Preferred Stock dividends, as well as an additional $19.0 million of Preferred Stock dividends that had been declared and paid as of period end Year ended September 30, 2018 amount is composed of $5.0 million in undeclared cumulative Preferred Stock dividends, as well as an additional $13.0 million of Preferred Stock dividends that had been declared and paid as of period end
[3]	See Note 5 for detailed calculations and further discussion.

Consolidated Statements of Op_2

Consolidated Statements of Operations (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Income Statement [Abstract]
Net income tax benefit		$ 49.2
Cumulative preferred stock dividends undeclared	$ 5	5
Preferred stock dividends declared and paid	$ 19	$ 13

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Statement Of Income And Comprehensive Income [Abstract]
Net income (loss)	$ (10,612)	$ 98,626	$ 100,864
Other comprehensive income (loss):
Foreign currency translation adjustment	(1,734)	(2,687)	3,706
Unrealized gain (loss) due to change in fair value of derivatives, net of tax	(1,612)	0	0
Total other comprehensive income (loss)	(3,346)	(2,687)	3,706
Comprehensive income (loss)	$ (13,958)	$ 95,939	$ 104,570

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands		Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Balance at Sep. 30, 2016		$ 1,323,827	$ 598	$ 694,564	$ 647,322	$ (18,657)
Balance (in shares) at Sep. 30, 2016			59,890,885
Issuance of common stock, net of shares withheld for taxes		8,627	$ 6	8,621	0	0
Issuance of common stock, net of shares withheld for taxes (Shares)			536,223
Issuance of common stock from secondary offering, net of issuance costs		329,323	$ 73	329,250	0	0
Issuance of common stock from secondary offering, net of issuance costs (Shares)			7,273,750
Stock-based compensation		15,071	$ 0	15,071	0	0
Other comprehensive income (loss)		4,094	0	0	0	4,094
Net income (loss)		100,864	0	0	100,864	0
Balance at Sep. 30, 2017		1,781,806	$ 677	1,047,506	748,186	(14,563)
Balance (in shares) at Sep. 30, 2017			67,700,858
Issuance of common stock, net of shares withheld for taxes		3,539	$ 4	3,535	0	0
Issuance of common stock, net of shares withheld for taxes (Shares)			434,932
Issuance costs related to secondary offering of common stock		(474)	$ 0	(474)	0	0
Stock-based compensation		16,473	0	16,473	0	0
Other comprehensive income (loss)		(2,687)	0	0	0	(2,687)
Net income (loss)		98,626	0	0	98,626	0
Dividends on preferred shares	[1]	(12,978)	0	0	(12,978)	0
Balance at Sep. 30, 2018		1,884,305	$ 681	1,067,040	833,834	(17,250)
Balance (in shares) at Sep. 30, 2018			68,135,790
Issuance of common stock, net of shares withheld for taxes		(354)	$ 4	(358)	0	0
Issuance of common stock, net of shares withheld for taxes (Shares)			438,386
Stock-based compensation		16,360	$ 0	16,360	0	0
Other comprehensive income (loss)		(3,346)	0	0	0	(3,346)
Net income (loss)		(10,612)	0	0	(10,612)	0
Dividends on preferred shares	[1]	(24,000)	0	0	(24,000)	0
Balance at Sep. 30, 2019		$ 1,862,353	$ 685	$ 1,083,042	$ 799,222	$ (20,596)
Balance (in shares) at Sep. 30, 2019			68,574,176
[1]	Amount represents dividends that have been declared and paid during the respective periods presented.

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Operating Activities
Net income (loss)	$ (10,612)	$ 98,626	$ 100,864
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	277,761	201,503	116,467
Stock-based compensation	16,360	16,473	15,071
Certain interest expense and other financing costs	12,102	17,338	10,497
Beneficial lease amortization	2,290	0	0
Loss on debt extinguishment	0	1,248	0
Gain on sale of fixed assets	(3,830)	(1,294)	(839)
Deferred income taxes	(2,555)	(30,118)	393
Changes in operating assets and liabilities, net of the effects of businesses acquired in the period:
Accounts receivable	(18,501)	(45,093)	(60,185)
Inventories	(82,774)	(65,069)	(51,768)
Prepaid expenses and other assets	(70,815)	57,554	(44,208)
Accounts payable and accrued expenses	92,133	287,428	228,908
Other liabilities	1,094	785	0
Net cash provided by (used in) operating activities	212,653	539,381	315,200
Investing Activities
Purchases of property and equipment	(57,031)	(46,010)	(39,828)
Acquisition of businesses, net	(163,973)	(2,740,480)	(129,390)
Proceeds from the sale of assets	9,269	2,149	2,233
Net cash provided by (used in) investing activities	(211,735)	(2,784,341)	(166,985)
Financing Activities
Borrowings under revolving lines of credit	2,100,085	2,807,741	2,464,128
Repayments under revolving lines of credit	(2,113,982)	(2,707,741)	(2,833,230)
Borrowings under term loan	0	970,000	0
Repayments under term loan	(9,700)	(445,850)	(4,500)
Borrowings under senior notes	0	1,300,000	0
Payment of debt issuance costs	(817)	(65,788)	(1,669)
Repayments under equipment financing facilities and other	(10,001)	(11,593)	(10,034)
Proceeds from issuance of convertible preferred stock	0	400,000	0
Proceeds from secondary offering of common stock	0	0	345,503
Payment of stock issuance costs	0	(1,279)	(14,684)
Payment of dividends on preferred stock	(24,000)	(12,978)	0
Proceeds from issuance of common stock related to equity awards	3,314	7,514	11,341
Taxes paid related to net share settlement of equity awards	(3,668)	(3,975)	(392)
Excess tax benefit from stock-based compensation	0	0	2,937
Net cash provided by (used in) financing activities	(58,769)	2,236,051	(40,600)
Effect of exchange rate changes on cash and cash equivalents	211	586	(751)
Net increase (decrease) in cash and cash equivalents	(57,640)	(8,323)	106,864
Cash and cash equivalents, beginning of period	129,927	138,250	31,386
Cash and cash equivalents, end of period	72,287	129,927	138,250
Cash paid during the period for:
Interest	146,425	111,283	49,067
Income taxes paid (received), net of refunds	$ (8,525)	$ 35,105	$ 56,158

Company Overview

Company Overview	12 Months Ended
	Sep. 30, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Company Overview	1. Company Overview Beacon Roofing Supply, Inc. (the “Company”) was incorporated in the state of Delaware on August 22, 1997 and is the largest publicly traded distributor of residential and non-residential roofing materials and complementary building products in the United States and Canada. The Company operates its business under regional and local trade names and services customers in all 50 states throughout the U.S. and 6 provinces in Canada. The Company’s material subsidiaries are Beacon Sales Acquisition, Inc., Allied Building Products LLC and Beacon Roofing Supply Canada Company.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Basis of Presentation The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All inter-company transactions have been eliminated. Certain prior period amounts have been reclassified to conform to current period presentation. Use of Estimates The preparation of consolidated financial statements in conformity with United States generally accepted accounting principles (“GAAP”) requires management to make estimates and assumptions that affect the amounts reported in these consolidated financial statements and accompanying notes. Significant items subject to such estimates include inventories, purchase price allocations, recoverability of goodwill and intangibles, and income taxes. Actual amounts could differ from those estimates. Fiscal Year The fiscal years presented are the years ended September 30, 2019 (“2019”), September 30, 2018 (“2018”), and September 30, 2017 (“2017”). Each of the Company’s first three quarters ends on the last day of the calendar month. Segment Information Operating segments are defined as components of a business that can earn revenue and incur expenses for which discrete financial information is evaluated on a regular basis by the chief operating decision maker (“CODM”) in order to decide how to allocate resources and assess performance. The Company’s CODM, the Chief Executive Officer, reviews consolidated results of operations to make decisions, therefore the Company views its operations and manages its business as one operating segment. Cash and Cash Equivalents The Company considers all highly liquid investments with maturities of three months or less when purchased to be cash equivalents. Cash and cash equivalents also include unsettled credit card transactions. Cash equivalents are comprised of money market funds which invest primarily in commercial paper or bonds with a rating of A-1 or better, and bank certificates of deposit. Accounts Receivable Accounts receivable are derived from unpaid invoiced amounts and are recorded at their net realizable value. The allowance for doubtful accounts is calculated based on actual historical write-offs and current economic factors and represents the Company’s best estimate of its credit exposure. Each month the Company reviews its receivables on a customer-by-customer basis and any balances that are deemed uncollectible are written off against the allowance after all means of collection have been exhausted and the potential for recovery is considered remote. The Company’s accounts receivable are primarily from customers in the building industry located in the United States and Canada, and no single customer represented at least 10% of the Company’s revenue during the year ended September 30, 2019 or accounts receivable as of September 30, 2019. Concentrations of Risk Financial instruments that potentially subject the Company to significant concentration of credit risk consist primarily of cash, cash equivalents and accounts receivable. The Company maintains the majority of its cash and cash equivalents with one financial institution, which management believes to be financially sound and with minimal credit risk. The Company’s deposits typically exceed amounts guaranteed by the Federal Deposit Insurance Corporation. Inventories Inventories, consisting substantially of finished goods, are valued at the lower of cost or market (net realizable value). Cost is determined using the moving weighted-average cost method. The Company’s arrangements with vendors typically provide for rebates after it makes a special purchase and/or monthly, quarterly and/or annual rebates of a specified amount of consideration payable when a number of measures have been achieved. Annual rebates are generally related to a specified cumulative level of purchases on a calendar-year basis. The Company accounts for such rebates as a reduction of the inventory value until the product is sold, at which time such rebates reduce cost of sales in the consolidated statements of operations. Throughout the year, the Company estimates the amount of the periodic rebates based upon the expected level of purchases. The Company continually revises these estimates to reflect actual rebates earned based on actual purchase levels. Amounts due from vendors under these arrangements are included in “prepaid expenses and other current assets” in the accompanying consolidated balance sheets. Property and Equipment Property and equipment acquired in connection with acquisitions are recorded at fair value as of the date of the acquisition and depreciated utilizing the straight-line method over the estimated remaining lives. All other additions are recorded at cost, and depreciation is computed using the straight-line method. The Company reviews the estimated useful lives of its fixed assets on an ongoing basis and the following table summarizes the estimates currently used: Asset Class Estimated Useful Life Buildings and improvements 40 years Equipment 3 to 7 years Furniture and fixtures 7 years Leasehold improvements Shorter of the estimated useful life or the term of the lease, considering renewal options expected to be exercised. Business Combinations The Company records acquisitions resulting in the consolidation of a business using the acquisition method of accounting. Under this method, the acquiring Company records the assets acquired, including intangible assets that can be identified and named, and liabilities assumed based on their estimated fair values at the date of acquisition. The Company uses an income approach to determine the fair value of acquired intangible assets, specifically the multi-period excess earnings method for customer relationships and the relief from royalty method for trade names. Various Level 3 fair value assumptions are used in the determination of these estimated fair values, including items such sales growth rates, cost synergies, customer attrition rates, discount rates, and other prospective financial information. The purchase price in excess of the fair value of the assets acquired and liabilities assumed is recorded as goodwill. Estimates associated with the accounting for acquisitions may change as additional information becomes available regarding the assets acquired and liabilities assumed. Transaction costs associated with acquisitions are expensed as incurred. Goodwill and Intangibles On an annual basis and at interim periods when circumstances require, the Company tests the recoverability of its goodwill and indefinite-lived intangible assets. Examples of such indicators include a significant change in the business climate, unexpected competition, loss of key personnel or a decline in the Company’s market capitalization below the Company’s net book value. The Company performs impairment assessments at the reporting unit level, which is defined as an operating segment or one level below an operating segment, also known as a component. The Company currently has five components which it evaluates for aggregation by examining the distribution methods, sales mix, and operating results of each component to determine if these characteristics will be sustained over a long-term basis. For purposes of this evaluation, the Company expects its components to exhibit similar economic characteristics 3-5 years after events such as an acquisition within the Company’s core roofing business or management/business restructuring. Components that exhibit similar economic characteristics are subsequently aggregated into a single reporting unit. Based on the Company’s most recent impairment assessment performed as of August 31, 2019, it was determined that all of the Company’s components exhibited similar economic characteristics, and therefore should be aggregated into a single reporting unit (collectively, the “Reporting Unit”). To test for the recoverability of goodwill and indefinite-lived intangible assets, the Company first performs a qualitative assessment based on economic, industry and company-specific factors for all or selected reporting units to determine whether the existence of events and circumstances indicates that it is more likely than not that the goodwill or indefinite-lived intangible asset is impaired. Based on the results of the qualitative assessment, two additional steps in the impairment assessment may be required. The first step would require a comparison of each reporting unit’s fair value to the respective carrying value. If the carrying value exceeds the fair value, a second step is performed to measure the amount of impairment loss on a relative fair value basis, if any. Based on the Company’s most recent qualitative impairment assessment performed as of August 31, 2019 , the Company concluded that there were no indicators of impairment, and that therefore it was more likely than not that the fair value of the goodwill and indefinite-lived intangible assets exceeded their net carrying amount, and therefore the quantitative two-step impairment test was not required. The Company amortizes certain identifiable intangible assets that have finite lives, currently consisting of non-compete agreements, customer relationships and trade names. Non-compete agreements are amortized on a straight-line basis over the terms of the associated contractual agreements; customer relationship assets are amortized on an accelerated basis based on the expected cash flows generated by the existing customers; and trade names are amortized on an accelerated basis over a five or ten year period. Amortizable intangible assets are tested for impairment, when deemed necessary, based on undiscounted cash flows and, if impaired, are written down to fair value based on either discounted cash flows or appraised values. In connection with certain financing arrangements, the Company has debt issuance costs that are amortized over the lives of the associated financings. Evaluation of Long-Lived Assets The Company evaluates the recoverability of its long-lived assets for impairment whenever events or circumstances indicate that the carrying amount of the assets may not be recoverable. Recoverability is measured by comparing the carrying amount of the asset to the future undiscounted cash flows the asset is expected to generate. If the asset is considered to be impaired, the amount of any impairment is measured as the difference between the carrying value and the fair value of the impaired asset. Fair Value Measurement The Company applies fair value accounting for all financial assets and liabilities that are reported at fair value in the financial statements on a recurring basis. Fair value is defined as the price that would be received from selling an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. The accounting guidance establishes a defined three-tier hierarchy to classify and disclose the fair value of assets and liabilities on both the date of their initial measurement as well as all subsequent periods. The hierarchy prioritizes the inputs used to measure fair value by the lowest level of input that is available and significant to the fair value measurement. The three levels are described as follows: • Level 1 : Observable inputs. Quoted prices in active markets for identical assets and liabilities; • Level 2 : Observable inputs other than the quoted price. Includes quoted prices for similar instruments, quoted prices for identical or similar instruments in inactive markets and amounts derived from valuation models where all significant inputs are observable in active markets; and • Level 3 : Unobservable inputs. Includes amounts derived from valuation models where one or more significant inputs are unobservable and require the Company to develop relevant assumptions. The Company evaluates its financial assets and liabilities subject to fair value measurements on a recurring basis to determine the appropriate level of classification as of each reporting period. Financial Derivatives The Company has entered into interest rate swaps to minimize the risks and costs associated with financing activities, as well as to maintain an appropriate mix of fixed-rate and floating-rate debt. The swap agreements are contracts to exchange variable-rate for fixed-interest rate payments over the life of the agreements. The Company's derivative instruments are designated as cash flow hedges, for which the Company records the effective portions of changes in their fair value, net of tax, in other comprehensive income. The Company recognizes any ineffective portion of the hedges in the consolidated statement of operations through interest expense, financing costs and other. Net Sales The Company records net sales when performance obligations with our customer are satisfied. A performance obligation is a promise to transfer a distinct good to the customer and is the unit of account. The transaction price is allocated to each distinct performance obligation and recognized as net sales when, or as, the performance obligation is satisfied. All contracts have a single performance obligation as the promise to transfer the individual good is not separately identifiable from other promises and is, therefore, not distinct. Performance obligations are satisfied at a point in time and net sales are recognized when the customer accepts the delivery of a product or takes possession of a product with rights and rewards of ownership. For goods shipped by third party carriers, the Company recognizes revenue upon shipment since the terms are generally FOB shipping point at which time control passes to the customer. The Company also arranges for certain products to be shipped directly from the manufacturer to the customer. The Company recognizes the gross revenue for these sales upon shipment as the terms are FOB shipping point at which time control passes to the customer. The Company enters into agreements with customers to offer rebates, generally based on achievement of specified sales levels and various marketing allowances that are common industry practice. Reductions to net sales for customer programs and incentive offerings, including promotions and other volume-based incentives, are estimated using the most likely amount method and recorded in the period in which the sale occurs. Provisions for early payment discounts are accrued in the same period in which the sale occurs. The Company does not have any material payment terms as payment is received shortly after the transfer of control of the products to the customer. Commissions to internal sales teams are paid to obtain contracts. As these contracts are less than one year, these costs are expensed as incurred. The Company includes shipping and handling costs billed to customers in net sales. Related costs are accounted for as fulfillment activities and are recognized as cost of products sold when control of the products transfers to the customer. Leases The Company leases the majority of its facilities and enters into various other operating lease agreements in conducting its business. At the inception of each lease, the Company evaluates the lease agreement to determine whether the lease is an operating or capital lease. Operating lease expenses are recognized in the statements of operations on a straight-line basis over the term of the related lease. Some of the Company’s lease agreements may contain renewal options, tenant improvement allowances, rent holidays or rent escalation clauses. When such items are included in a lease agreement, the Company records a deferred rent asset or liability on the consolidated balance sheets equal to the difference between the rent expense and cash rent payments. The cost of property and equipment acquired under capital lease arrangements represents the lesser of the present value of the minimum lease payments or the fair value of the leased asset as of the inception of the lease. Stock-Based Compensation The Company applies the fair value method to recognize compensation expense for stock-based awards. Using this method, the estimated grant-date fair value of the award is recognized on a straight-line basis over the requisite service period based on the portion of the award that is expected to vest. The Company estimates forfeitures at the time of grant and revises the estimates, if necessary, in subsequent periods if actual forfeitures differ from those estimates. For awards with a performance-based vesting condition, the Company accrues stock-based compensation expense if it is probable that the performance condition will be achieved. Stock-based compensation expense for restricted stock units is measured based on the fair value of the Company’s common stock on the grant date. The Company utilizes the Black-Scholes option pricing model to estimate the grant-date fair value of option awards. The exercise price of option awards is set to equal the estimated fair value of the common stock at the date of the grant. The following weighted-average assumptions are also used to calculate the estimated fair value of option awards: • Expected volatility : The expected volatility of the Company’s shares is estimated using the historical stock price volatility over the most recent period commensurate with the estimated expected term of the awards. • Expected term : For employee stock option awards, the Company determines the weighted average expected term equal to the weighted period between the vesting period and the contract life of all outstanding options. • Dividend yield : The Company has not paid dividends and does not anticipate paying a cash dividend in the foreseeable future and, accordingly, uses an expected dividend yield of zero. • Risk-free interest rate : The Company bases the risk-free interest rate on the implied yield available on a U.S. Treasury note with a term equal to the estimated expected term of the awards. Foreign Currency Translation The Company’s operations located outside of the United States where the local currency is the functional currency are translated into U.S. dollars using the current rate method. Results of operations are translated at the average rate of exchange for the period. Assets and liabilities are translated at the closing rates on the period end date. Gains and losses on translation of these accounts are accumulated and reported as a separate component of equity and other comprehensive income (loss). Gains and losses on foreign currency transactions are recognized in the consolidated statements of operations as a component of interest expense, financing costs, and other. Income Taxes The Company accounts for income taxes using the liability method, which requires it to recognize a current tax liability or asset for current taxes payable or refundable and a deferred tax liability or asset for the estimated future tax effects of temporary differences between the financial statement and tax reporting bases of assets and liabilities to the extent that they are realizable. Deferred tax expense (benefit) results from the net change in deferred tax assets and liabilities during the year. FASB ASC Topic 740 prescribes a recognition threshold and measurement attribute for the financial statement recognition and measurement of a tax position taken or expected to be taken in a tax return. Based on this guidance, the Company analyzes its filing positions in all of the federal and state jurisdictions where it is required to file income tax returns, as well as all open tax years in these jurisdictions. Tax benefits from uncertain tax positions are recognized if it is more likely than not that the position is sustainable based solely on its technical merits. Net Income (Loss) per Share Basic net income (loss) per share is calculated by dividing net income (loss) attributable to common shareholders by the weighted-average number of common shares outstanding during the period, without consideration for common share equivalents or the conversion of Preferred Stock. Common share equivalents consist of the incremental common shares issuable upon the exercise of stock options and vesting of restricted stock unit awards. Diluted net income (loss) per common share is calculated by dividing net income (loss) attributable to common shareholders by the fully diluted weighted-average number of common shares outstanding during the period. Holders of Preferred Stock participate in dividends on an as-converted basis when declared on common shares. As a result, Preferred Stock is classified as a participating security and thereby requires the allocation of income that would have otherwise been available to common shareholders when calculating net income (loss) per share. Diluted net income (loss) per share is calculated by utilizing the most dilutive result of the if-converted and two-class methods. In both methods, net income (loss) attributable to common shareholders and the weighted-average common shares outstanding are adjusted to account for the impact of the assumed issuance of potential common shares that are dilutive, subject to dilution sequencing rules. Recent Accounting Pronouncements—Adopted In May 2014, the FASB issued ASU 2014-09, “ Revenue from Contracts with Customers In January 2017, the FASB issued ASU 2017-01, “ Business Combinations: Clarifying the Definition of a Business In March 2017, the FASB issued ASU 2017-07, " Compensation—Retirement Benefits (Topic 715), Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost In May 2017, the FASB issued ASU 2017-09, “ Scope of Modification Accounting .” This guidance is intended to provide clarity and reduce both diversity in practice and cost and complexity when applying the guidance in Compensation – Stock Compensation, to a change to the terms or conditions of a share-based payment award. This new standard is effective for annual reporting periods, and interim reporting periods contained therein, beginning after December 15, 2017. The Company adopted the standard as of October 1, 2018 and the standard did not have a material impact on the Company’s financial statements and related disclosures. In August 2017, the FASB issued ASU 2017-12, “ Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities In June 2018, the FASB issued ASU 2018-07, “ Compensation—Stock Compensation (Topic 718), Improvements to Nonemployee Share-Based Payment Accounting Recent Accounting Pronouncements—Not Yet Adopted In February 2016, the FASB issued ASU 2016-02, “ Leases In June 2016, the FASB issued ASU 2016-13, “ Financial Instruments—Credit Losses: Measurement of Credit Losses on Financial Instruments In January 2017, the FASB issued ASU 2017-04, “ Simplifying the Accounting for Goodwill Impairment In February 2018, the FASB issued ASU 2018-02, “ Income Statement—Reporting Comprehensive Income

Acquisitions

Acquisitions	12 Months Ended
	Sep. 30, 2019
Business Combinations [Abstract]
Acquisitions	3. Acquisitions Allied Building Products Corp. On January 2, 2018 (the “Closing Date”), the Company completed its acquisition of all the outstanding capital stock of Allied (the “Allied Acquisition”), pursuant to a certain stock purchase agreement dated August 24, 2017 (the “Stock Purchase Agreement”), among the Company, Oldcastle, Inc., as parent, and Oldcastle Distribution, Inc., as seller, for approximately $2.625 billion in cash, subject to a working capital and certain other adjustments as set forth in the Stock Purchase Agreement (the “Purchase Price”). As of September 30, 2019 , the adjusted Purchase Price for Allied was $2.88 billion , including increases of (i) $ 164.0 million related to the impact of the Section 338(h)(10) election under the current U.S. tax code and (ii) $ 88.1 million from a recorded net working capital adjustment. In connection with the Allied Acquisition, on the Closing Date the Company entered into (i) a new term loan agreement with Citibank, N.A., providing for a term loan B facility with an initial commitment of $970.0 million and (ii) an amended and restated credit agreement with Wells Fargo Bank, N.A., providing for a senior secured asset-based revolving credit facility with an initial commitment of $1.30 billion. Base borrowing rates on these facilities are at LIBOR plus 1.25% and LIBOR plus 2.25%, respectively. In connection with the Allied Acquisition, on the Closing Date, the Company completed the sale of 400,000 shares of Series A Cumulative Convertible Participating Preferred Stock, par value $0.01 per share (the “Preferred Stock”), with an aggregate liquidation preference of $400.0 million, at a purchase price of $1,000 per share, to CD&R Boulder Holdings, L.P., pursuant to an investment agreement, dated as of August 24, 2017, with CD&R Boulder Holdings, L.P. and Clayton, Dubilier & Rice Fund IX, L.P. (solely for the purpose of limited provisions therein) (the “Convertible Preferred Stock Purchase”). The $400.0 million in proceeds from the Convertible Preferred Stock Purchase were used to finance, in part, the Purchase Price. The Preferred Stock is convertible perpetual participating preferred stock of the Company, and conversion of the Preferred Stock into $0.01 par value shares of the Company’s common stock will be at a conversion price of $41.26 per share. The Preferred Stock accumulates dividends at a rate of 6.0% per annum (payable in cash or in-kind, subject to certain conditions). The Preferred Stock is not mandatorily redeemable; therefore, it is classified as mezzanine equity on the Company’s consolidated balance sheets and has a balance of $399.2 million (the $400.0 million proceeds received on the Closing Date, net of $0.8 million of unamortized issuance costs) as of September 30, 2019. Allied’s results of operations have been included with Company’s consolidated results beginning January 2, 2018. Allied distributed products in 208 locations across 31 states as of the date of the close. The Allied Acquisition has been accounted for as a business combination in accordance with the requirements of ASC 805, “ Business Combinations January 2, 2018 January 2, 2018 (as reported at March 31, 2018) Adjustments (as adjusted at March 31, 2019) Cash $ 19,322 $ (19,153 ) $ 169 Accounts receivable 315,485 22,064 337,549 Inventory 322,705 (7,920 ) 314,785 Prepaid and other current assets 59,279 16,161 75,440 Property, plant, and equipment 139,528 (168 ) 139,360 Goodwill 1,130,635 102,145 1,232,780 Intangible assets 1,037,000 - 1,037,000 Current liabilities (271,252 ) 11,963 (259,289 ) Non-current liabilities (6,820 ) 6,097 (723 ) Total purchase price $ 2,745,882 $ 131,189 $ 2,877,071 The purchase accounting entries above include the impact of the Section 338(h)(10) election under the current U.S. tax code. The Company made this election on October 15, 2018 and has reflected the $164.0 million impact of this election in the purchase price and its fiscal year 2018 tax provision accordingly. The Company determined that $1.10 billion of goodwill related to the acquisition of Allied remains deductible for tax purposes as of September 30, 2019. All of the Company’s goodwill and indefinite-lived trade name are tested for impairment annually, and all acquired goodwill and intangible assets are subject to review for impairment should future indicators of impairment develop. There were no material contingencies assumed as part of the Allied Acquisition. Additional Acquisitions – Fiscal Year 2018 During fiscal year 2018, the Company acquired 7 branches from the following two acquisitions: • On May 1, 2018, the Company acquired Tri-State Builder’s Supply, a wholesale supplier of roofing, siding, windows, doors and related building products with 1 branch located in Duluth, Minnesota and annual sales of approximately $6 million. The Company has finalized the acquisition accounting entries for this transaction. • On July 16, 2018, the Company acquired Atlas Supply, Inc., the Pacific Northwest’s leading distributor of sealants, coatings, adhesives and related waterproofing products, with 6 branches operating in Seattle, Tacoma, Spokane, and Mountlake Terrace in Washington, as well as locations in Portland, Oregon and Boise, Idaho, and annual sales of approximately $37 million. The Company has finalized the acquisition accounting entries for this transaction. The Company has recorded purchase accounting entries for these transactions that recognized the acquired assets and liabilities at their estimated fair values as of the respective acquisition dates. These transactions resulted in goodwill of $7.6 million ($7.0 million of which remains deductible for tax purposes as of September 30, 2019) and $11.4 million in intangible assets. Additional Acquisitions – Fiscal Year 2017 During fiscal year 2017, the Company acquired 23 branches from the following five acquisitions: • On December 16, 2016, the Company purchased certain assets of BJ Supply Company, a distributor of roofing and related building products with 1 branch serving Pennsylvania and New Jersey and annual sales of approximately $4 million. The Company has finalized the acquisition accounting entries for this transaction. • On January 3, 2017, the Company acquired American Building & Roofing, Inc., a distributor of mainly residential roofing and related building products with 7 branches around Washington State and annual sales of approximately $36 million. The Company has finalized the acquisition accounting entries for this transaction. • On January 9, 2017, the Company acquired Eco Insulation Supply, a distributor of insulation and related accessories with 1 branch serving Connecticut, Southern New England and the New York City metropolitan area and annual sales of approximately $8 million. The Company has finalized the acquisition accounting entries for this transaction. • On March 1, 2017, the Company acquired Acme Building Materials, Inc., a distributor of residential roofing and related building products with 3 branches in Eastern Michigan and annual sales of approximately $13 million. The Company has finalized the acquisition accounting entries for this transaction. • On May 1, 2017, the Company purchased certain assets of Lowry’s Inc., a distributor of waterproofing and concrete restoration materials with 11 branches operating in California, Arizona, Utah and Hawaii and annual sales of approximately $76 million. The Company has finalized the acquisition accounting entries for this transaction. The Company has recorded purchase accounting entries for these transactions that recognized the acquired assets and liabilities at their estimated fair values as of the respective acquisition dates. These transactions resulted goodwill of $53.0 million (all of which is deductible for tax purposes) and $47.4 million in intangible assets.

Net Sales

Net Sales	12 Months Ended
	Sep. 30, 2019
Revenue From Contract With Customer [Abstract]
Net Sales	4. Net Sales The following table presents the Company’s net sales by product line and geography for the year ended September 30, 2019 (in thousands): Year Ended September 30, 2019 U.S. Canada Total Residential roofing products $ 3,023,266 $ 56,362 $ 3,079,628 Non-residential roofing products 1,582,757 122,421 1,705,178 Complementary building products 2,312,496 7,858 2,320,354 Total net sales $ 6,918,519 $ 186,641 $ 7,105,160

Net Income (Loss) Per Share

Net Income (Loss) Per Share	12 Months Ended
	Sep. 30, 2019
Earnings Per Share [Abstract]
Net Income (Loss) Per Share	5. Net Income (Loss) Per Share The following table presents the components and calculations of basic and diluted net income (loss) per share for each period presented (in thousands, except share and per share amounts): Year Ended September 30, 2019 2018 2017 Net income (loss) $ (10,612 ) $ 98,626 $ 100,864 Dividends on preferred shares 24,000 18,000 - Net income (loss) attributable to common shareholders $ (34,612 ) $ 80,626 $ 100,864 Undistributed income allocated to participating securities - (7,742 ) - Net income (loss) attributable to common shareholders - basic and diluted $ (34,612 ) $ 72,884 $ 100,864 Weighted-average common shares outstanding - basic 68,424,288 68,012,879 60,315,648 Effect of common share equivalents - 1,178,160 1,028,615 Weighted-average common shares outstanding - diluted 68,424,288 69,191,039 61,344,263 Net income (loss) per share - basic $ (0.51 ) $ 1.07 $ 1.67 Net income (loss) per share - diluted $ (0.51 ) $ 1.05 $ 1.64 The following table includes the number of shares that may be dilutive common shares in the future. These shares were not included in the computation of diluted net income (loss) per share because the effect was either anti-dilutive or the requisite performance conditions were not met: Year Ended September 30, 2019 2018 2017 Stock options 1,336,259 388,731 331,681 Restricted stock units 122,278 192,151 61,890 Preferred Stock 9,694,619 7,224,483 -

Prepaid Expenses and Other Curr

Prepaid Expenses and Other Current Assets	12 Months Ended
	Sep. 30, 2019
Prepaid Expenses And Other Current Assets [Abstract]
Prepaid Expenses and Other Current Assets	6. Prepaid Expenses and Other Current Assets The following table summarizes the significant components of prepaid expenses and other current assets (in thousands): September 30, 2019 2018 Vendor rebates $ 262,876 $ 199,725 Other 52,767 44,635 Total prepaid expenses and other current assets $ 315,643 $ 244,360

Property and Equipment

Property and Equipment	12 Months Ended
	Sep. 30, 2019
Property Plant And Equipment [Abstract]
Property and Equipment	7. Property and Equipment The following table provides a detailed breakout of property and equipment, by type (in thousands): September 30, 2019 2018 Land and buildings $ 83,373 $ 82,991 Equipment 448,072 419,385 Furniture and fixtures 39,986 34,901 Total property and equipment 571,431 537,277 Accumulated depreciation (311,055 ) (256,870 ) Total property and equipment, net $ 260,376 $ 280,407 Depreciation expense for the years ended September 30, 2019, 2018, and 2017 was $70.7 million, $60.3 million, and $34.0 million, respectively.

Goodwill and Intangible Assets

Goodwill and Intangible Assets	12 Months Ended
	Sep. 30, 2019
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	8. Goodwill and Intangible Assets Goodwill The following table sets forth the change in the carrying amount of goodwill during the years ended September 30, 2019 and 2018, respectively (in thousands): Balance as of September 30, 2017 $ 1,251,986 Acquisitions 1,240,913 Translation and other adjustments (1,120 ) Balance as of September 30, 2018 $ 2,491,779 Balance as of September 30, 2018 $ 2,491,779 Acquisitions 1 (513 ) Translation and other adjustments (676 ) Balance as of September 30, 2019 $ 2,490,590 ____________________________ 1 Reflects purchase accounting adjustments related to fiscal year 2018 acquisition of Atlas Supply, Inc. (see Note 3 for further discussion). The change in the carrying amount of goodwill for the year ended September 30, 2019 was driven primarily by purchase accounting and foreign currency translation adjustments. The change in the carrying amount of goodwill for the year ended September 30, 2018 was driven primarily by acquisitions finalized during the period (see Note 3 for further discussion). The Company has recognized no goodwill impairments for any of the periods presented. Intangible Assets In connection with transactions finalized for the year ended September 30, 2018, the Company recorded intangible assets of $1.05 billion ($920.8 million of customer relationships, $7.0 million of beneficial lease arrangements, and $120.0 million of indefinite-lived trademarks). The following table summarizes intangible assets by category (in thousands, except time period amounts): September 30, Weighted- Average Remaining Life 1 2019 2018 (Years) Amortizable intangible assets: Non-compete agreements $ 2,824 $ 2,824 2.49 Customer relationships 1,530,970 1,530,565 17.65 Trademarks 10,500 10,500 6.92 Beneficial lease arrangements 8,060 8,060 3.59 Total amortizable intangible assets 1,552,354 1,551,949 Accumulated amortization (619,864 ) (410,633 ) Total amortizable intangible assets, net $ 932,490 $ 1,141,316 Indefinite lived trademarks 193,050 193,050 Total intangibles, net $ 1,125,540 $ 1,334,366 1 For the years ended September 30, 2019, 2018, and 2017, the Company recorded $207.1 million, $141.2 million, and $82.5 million, respectively, of amortization expense relating to the above-listed intangible assets. The intangible asset lives range from 5 to 20 years and the weighted-average remaining life was 17.5 years as of September 30, 2019. The following table summarizes the estimated future amortization expense for intangible assets (in thousands): Year Ending September 30, 2020 $ 179,549 2021 149,980 2022 121,431 2023 97,522 2024 78,873 Thereafter 305,135 Total future amortization expense $ 932,490

Financing Arrangements

Financing Arrangements	12 Months Ended
	Sep. 30, 2019
Debt Disclosure [Abstract]
Financing Arrangements	9. Financing Arrangements The following table summarizes all financing arrangements from the respective periods presented (in thousands): September 30, 2019 2018 Revolving Lines of Credit 2023 ABL: U.S. Revolver, expires January 2023 1 $ 80,961 $ 89,352 Canada Revolver, expires January 2023 2 - 3,090 Current portion - - Borrowings under revolving lines of credit, net $ 80,961 $ 92,442 Long-term Debt, net Term Loans: Term Loan, matures January 2025 3 $ 926,535 $ 930,726 Current portion (9,700 ) (9,700 ) Long-term borrowings under term loans 916,835 921,026 Senior Notes: Senior Notes, mature October 2023 4 294,886 293,607 Senior Notes, mature November 2025 5 1,282,902 1,280,092 Current portion - - Long-term borrowings under senior notes 1,577,788 1,573,699 Long-term debt, net $ 2,494,623 $ 2,494,725 Equipment Financing Facilities and Other Equipment financing facilities, various maturities through September 2021 6 $ 6,885 $ 11,222 Capital lease obligations, various maturities through November 2021 7 6,713 12,378 Current portion (8,989 ) (9,961 ) Long-term obligations under equipment financing and other, net $ 4,609 $ 13,639 ____________________________________________________________ 1 2 3 4 5 6 7 Financing - Allied Acquisition In connection with the Allied Acquisition, the Company entered into various financing arrangements totaling $3.57 billion, including an asset-based revolving line of credit of $1.30 billion (“2023 ABL”), $525.0 million of which was drawn at closing, and a $970.0 million term loan (“2025 Term Loan”). The Company also raised an additional $1.30 billion through the issuance of senior notes (the “2025 Senior Notes”). The proceeds from these financing arrangements were used to finance the Allied Acquisition, to refinance or otherwise extinguish all third-party indebtedness, to pay fees and expenses associated with the acquisition, and to provide working capital and funds for other general corporate purposes. The Company capitalized new debt issuance costs totaling approximately $65.3 million related to the 2023 ABL, the 2025 Term Loan and the 2025 Senior Notes. Since the financing arrangements entered into in connection with the Allied Acquisition had certain lenders who also participated in previous financing arrangements entered into by the Company, portions of the transactions were accounted for as either a debt modification or a debt extinguishment. In accordance with the accounting for debt modification, the Company expensed $2.0 million of debt issuance costs related to the Allied financing arrangements and recognized a loss on debt extinguishment of $1.2 million. The remainder of the debt issuance costs will be amortized over the term of the Allied financing arrangements. 2023 ABL On January 2, 2018, the Company entered into a $1.30 billion asset-based revolving line of credit with Wells Fargo Bank, N.A. and a syndicate of other lenders. The 2023 ABL consists of revolving loans in both the United States (“2023 U.S. Revolver”) in the amount of $1.20 billion and Canada (“2023 Canada Revolver”) in the amount of $100.0 million. The 2023 ABL has a maturity date of January 2, 2023. The 2023 ABL has various borrowing tranches with an interest rate based on a LIBOR rate (with a floor) plus a fixed spread. The current unused commitment fees on the 2023 ABL are 0.25% per annum. There is one financial covenant under the 2023 ABL, which is a Consolidated Fixed Charge Ratio. The Consolidated Fixed Charge Ratio is calculated by dividing consolidated earnings before interest, taxes, depreciation and amortization (EBITDA) by Consolidated Fixed Charges (both as defined in the agreement). Per the covenant, the Company’s Consolidated Fixed Charge Ratio must be a minimum of 1.00 at the end of each fiscal quarter, calculated on a trailing four quarter basis. The Company was in compliance with this covenant as of September 30, 2019. The 2023 ABL is secured by a first priority lien over substantially all of the Company’s and each guarantor’s accounts, chattel paper, deposit accounts, books, records and inventory (as well as intangibles related thereto), subject to certain customary exceptions (the “ABL Priority Collateral”), and a second priority lien over substantially all of the Company’s and each guarantor’s other assets, including all of the equity interests of any subsidiary held by the Company or any guarantor, subject to certain customary exceptions (the “Term Priority Collateral”). The 2023 ABL is guaranteed jointly, severally, fully and unconditionally by the Company’s active United States subsidiaries. As of September 30, 2019, the total balance outstanding on the 2023 ABL, net of $8.1 million of unamortized debt issuance costs, was $81.0 million. The Company also has outstanding standby letters of credit related to the 2023 U.S. Revolver in the amount of $13.3 million as of September 30, 2019. 2025 Term Loan On January 2, 2018, the Company entered into a $970.0 million Term Loan with Citibank N.A., and a syndicate of other lenders. The 2025 Term Loan requires quarterly principal payments in the amount of $2.4 million, with the remaining outstanding principal to be paid on its January 2, 2025 maturity date. The interest rate is based on a LIBOR rate (with a floor) plus a fixed spread. The Company has the option of selecting a LIBOR period that determines the rate at which interest can accrue on the Term Loan as well as the period in which interest payments are made. The 2025 Term Loan is secured by a first priority lien on the Term Priority Collateral and a second priority lien on the ABL Priority Collateral. Certain excluded assets will not be included in the Term Priority Collateral and the ABL Priority Collateral. The Term Loan is guaranteed jointly, severally, fully and unconditionally by the Company’s active United States subsidiaries. As of September 30, 2019, the outstanding balance on the 2025 Term Loan, net of $28.9 million of unamortized debt issuance costs, was $926.5 million. 2025 Senior Notes On October 25, 2017, Beacon Escrow Corporation, a wholly owned subsidiary of the Company (the “Escrow Issuer”), completed a private offering of $1.30 billion aggregate principal amount of 4.875% Senior Notes due 2025 at an issue price of 100%. The 2025 Senior Notes bear interest at a rate of 4.875 Upon closing of the Allied Acquisition on January 2, 2018, (i) the Escrow Issuer merged with and into the Company, and the Company assumed all obligations under the 2025 Senior Notes; and (ii) all existing domestic subsidiaries of the Company (including the entities acquired in the Allied Acquisition) became guarantors of the 2025 Senior Notes. As of September 30, 2019, the outstanding balance on the 2025 Senior Notes, net of $17.1 million of unamortized debt issuance costs, was $1.28 billion. Financing - RSG Acquisition In connection with the Roofing Supply Group (“RSG”) acquisition in fiscal year 2016, the Company entered into various financing arrangements totaling $1.45 billion, including an asset-based revolving line of credit (“2020 ABL”) of $700.0 million ($350.0 million of which was drawn at closing) and a $450.0 million term loan (“2022 Term Loan”). The Company also raised an additional $300.0 million through the issuance of senior notes (the “2023 Senior Notes”). The proceeds from these financing arrangements were used to provide working capital and funds for other general corporate purposes, to refinance or otherwise extinguish all third-party indebtedness, to finance the acquisition, and to pay fees and expenses associated with the RSG acquisition. The Company incurred debt issuance costs totaling approximately $31.3 million related to the 2020 ABL, 2022 Term Loan and 2023 Senior Notes. 2020 ABL On October 1, 2015, the Company entered into a $700.0 million asset-based revolving line of credit with Wells Fargo Bank, N.A. and a syndicate of other lenders. The 2020 ABL had an original maturity date of October 1, 2020 and consisted of revolving loans in both the United States, in the amount of $670.0 million, and Canada, in the amount of $30.0 million. The 2020 ABL had various borrowing tranches with an interest rate based on a LIBOR rate (with a floor) plus a fixed spread. The full balance of the 2020 ABL was paid on January 2, 2018 in conjunction with the Allied Acquisition. 2022 Term Loan On October 1, 2015, the Company entered into a $450.0 million Term Loan with Citibank N.A., and a syndicate of other lenders. The 2022 Term Loan required quarterly principal payments in the amount of $1.1 million, with the remaining outstanding principal to be paid on its original maturity date of October 1, 2022. The interest rate was based on a LIBOR rate (with a floor) plus a fixed spread. The Company had the option of selecting a LIBOR period that determined the rate at which interest would accrue, as well as the period in which interest payments are made. The full balance of the 2022 Term Loan was paid on January 2, 2018 in conjunction with the Allied Acquisition, including the write-off of $0.7 million in debt issuance costs. 2023 Senior Notes On October 1, 2015, the Company raised $300.0 million by issuing senior notes due 2023. The 2023 Senior Notes have a coupon rate of 6.38% per annum and are payable semi-annually in arrears, beginning April 1, 2016. There are early payment provisions in the indenture in which the Company would be subject to “make whole” provisions. The 2023 Senior Notes are guaranteed jointly, severally, fully and unconditionally by the Company’s active United States subsidiaries. As of September 30, 2019, the outstanding balance on the 2023 Senior Notes, net of $5.1 million of unamortized debt issuance costs, was $294.9 million. In October 2019, the 2023 Senior Notes were fully redeemed and replaced in connection with re-financing efforts (see Note 20 for additional information). Other Information Annual principal payments for all outstanding financing arrangements for each of the next five years and thereafter are as follows (in thousands): Year Ending September 30, 2023 ABL 2025 Term Loan Senior Notes 1 Equipment Financing and Other Total 2020 $ - $ 9,700 $ - $ 8,989 $ 18,689 2021 - 9,700 - 4,367 14,067 2022 - 9,700 - 213 9,913 2023 89,104 9,700 300,000 29 398,833 2024 - 9,700 - - 9,700 Thereafter - 906,950 1,300,000 - 2,206,950 Total debt 89,104 955,450 1,600,000 13,598 2,658,152 Unamortized debt issuance costs (8,143 ) (28,915 ) (22,212 ) - (59,270 ) Total long-term debt $ 80,961 $ 926,535 $ 1,577,788 $ 13,598 $ 2,598,882 1 Under the terms of the 2023 ABL, the 2025 Term Loan, the 2025 Senior Notes and the 2023 Senior Notes, the Company is limited in making certain restricted payments, including dividends on its common stock. Based on the provisions in the respective debt agreements and given the Company’s intention to not pay common stock dividends in the foreseeable future, the Company does not believe that the restrictions are significant.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Sep. 30, 2019
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	10. Commitments and Contingencies Operating Leases The Company mostly operates in leased facilities, which are accounted for as operating leases. The leases typically provide for a base rent plus real estate taxes. Certain of the leases provide for escalating rents over the lives of the leases and rent expense is recognized over the terms of those leases on a straight-line basis. At September 30, 2019, the minimum rental commitments under all non-cancelable operating leases with initial or remaining terms of more than one year were as follows (in thousands): Year Ending September 30, 2020 $ 110,858 2021 103,185 2022 88,086 2023 70,839 2024 54,185 Thereafter 100,256 Total minimum lease payments $ 527,409 Rent expense was $110.6 million, $99.1 million, and $60.1 million for the years ended September 30, 2019, 2018, and 2017, respectively. Sublet income was immaterial for each of these periods. Contingencies The Company is subject to loss contingencies pursuant to various federal, state and local environmental laws and regulations; however, the Company is not aware of any reasonably possible losses that would have a material impact on its results of operations, financial position, or liquidity. Potential loss contingencies include possible obligations to remove or mitigate the effects on the environment of the placement, storage, disposal or release of certain chemical or other substances by the Company or by other parties. In connection with its acquisitions, the Company’s practice is to request indemnification for any and all known material liabilities of significance as of the respective dates of acquisition. Historically, environmental liabilities have not had a material impact on the Company’s results of operations, financial position or liquidity. The Company is subject to litigation from time to time in the ordinary course of business; however the Company does not expect the results, if any, to have a material adverse impact on its results of operations, financial position or liquidity.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss)	12 Months Ended
	Sep. 30, 2019
Equity [Abstract]
Accumulated Other Comprehensive Income (Loss)	11. Accumulated Other Comprehensive Income (Loss) Other comprehensive income (loss) is comprised of certain gains and losses that are excluded from net income under GAAP and instead recorded as a separate element of stockholders’ equity. The following table summarizes the components of and changes in accumulated other comprehensive loss (in thousands): Foreign Derivative Accumulated Other Currency Translation Financial Instruments Comprehensive Loss Balance as of September 30, 2016 $ (18,269 ) $ (388 ) $ (18,657 ) Other comprehensive loss before reclassifications 3,706 - 3,706 Reclassifications out of other comprehensive loss - 388 388 Balance as of September 30, 2017 $ (14,563 ) $ - $ (14,563 ) Other comprehensive income before reclassifications (2,687 ) - (2,687 ) Reclassifications out of other comprehensive loss - - - Balance as of September 30, 2018 $ (17,250 ) $ - $ (17,250 ) Other comprehensive income before reclassifications (1,734 ) (1,612 ) (3,346 ) Reclassifications out of other comprehensive loss - - - Balance as of September 30, 2019 $ (18,984 ) $ (1,612 ) $ (20,596 ) Gains (losses) on derivative instruments are recognized in the consolidated statements of operations in interest expense, financing costs, and other.

Stock-based Compensation

Stock-based Compensation	12 Months Ended
	Sep. 30, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-based Compensation	12. Stock-based Compensation The Company is authorized to issue 100 million shares of common stock. There were 68,574,176 and 68,135,790 shares of common stock issued and outstanding as of September 30, 2019 and 2018, respectively. On February 9, 2016, the shareholders of the Company approved the Amended and Restated Beacon Roofing Supply, Inc. 2014 Stock Plan (the “2014 Plan”). The 2014 Plan provides for discretionary awards of stock options, stock awards, restricted stock units, and stock appreciation rights (“SARs”) for up to 5,000,000 shares of common stock to selected employees and non-employee directors. The 2014 Plan mandates that all forfeited, expired, and withheld shares, including those from the predecessor plans, be returned to the 2014 Plan and made available for issuance. As of September 30, 2019, there were 1,781,109 shares of common stock available for issuance. Prior to the 2014 Plan, the Company maintained the amended and restated Beacon Roofing Supply, Inc. 2004 Stock Plan (the “2004 Plan”). Upon shareholder approval of the 2014 Plan, the Company ceased issuing equity awards from the 2004 Plan and mandated that all future equity awards will be issued from the 2014 Plan. For all equity awards granted prior to October 1, 2014, in the event of a change in control of the Company, all awards are immediately vested. Beginning in fiscal 2015, equity awards contained a “double trigger” change in control mechanism. Unless an award is continued or assumed by a public company in an equitable manner, an award shall become fully vested immediately prior to a change in control (at 100% of the grant target in the case of a performance-based restricted stock unit award). If an award is so continued or assumed, vesting will continue in accordance with the terms of the award, unless there is a qualifying termination within one-year following the change in control, in which event the award shall immediately become fully vested (at 100% of the grant target in the case of a performance-based restricted stock unit award). Stock Options Non-qualified stock options generally expire 10 years after the grant date and, except under certain conditions, the options are subject to continued employment and vest in three annual installments over the three-year The fair values of the options granted for the year ended September 30, 2019 were estimated on the dates of grants using the Black-Scholes option-pricing model with the following weighted-average assumptions: Year Ended September 30, 2019 2018 2017 Risk-free interest rate 2.86 % 2.10 % 1.97 % Expected volatility 29.68 % 26.43 % 28.83 % Expected life (in years) 5.22 5.46 5.30 Dividend yield - - - The following table summarizes all stock option activity for the periods presented (in thousands, except share, per share, and time period amounts): Options Outstanding Weighted- Average Exercise Price Weighted- Average Remaining Contractual Term (Years) Aggregate Intrinsic Value 1 Balance as of September 30, 2018 1,969,037 $ 33.08 5.7 $ 14,088 Granted 674,015 27.67 Exercised (183,347 ) 18.08 Canceled/Forfeited (117,108 ) 35.18 Expired (3,108 ) 26.74 Balance as of September 30, 2019 2,339,489 $ 32.61 6.1 $ 12,034 Vested and expected to vest after September 30, 2019 2,305,869 $ 32.62 6.1 $ 11,870 Exercisable as of September 30, 2019 1,484,158 $ 31.54 4.5 $ 8,343 ___________________________________________________________________________ 1 During the years ended September 30, 2019, 2018, and 2017, the Company recorded stock-based compensation expense related to stock options of $4.1 million, $3.9 million, and $4.8 million, respectively. As of September 30, 2019, there was $5.4 million of total unrecognized compensation cost related to unvested stock options, which is expected to be recognized over a weighted-average period of 1.9 years. The following table summarizes additional information on stock options for the periods presented (in thousands, except per share amounts): Year Ended September 30, 2019 2018 2017 Weighted-average fair value of stock options granted $ 8.91 $ 15.86 $ 14.21 Total grant date fair value of stock options vested 3,850 4,208 5,541 Total intrinsic value of stock options exercised 2,849 9,645 10,941 Restricted Stock Units Restricted stock unit (“RSU”) awards granted to employees are subject to continued employment and generally vest on the third anniversary of the grant date. The Company also grants certain RSU awards to management that contain one or more additional vesting conditions tied directly to a defined performance metric for the Company. The actual number of RSUs that will vest can range from 0% to 200% of the original grant amount, depending upon actual Company performance below or above the established performance metric targets. The Company estimates performance in relation to the defined targets when determining the projected number of RSUs that are expected to vest and calculating the related stock-based compensation expense. RSUs granted to non-employee directors are subject to continued service and vest on the first anniversary of the grant date (except under certain conditions). Generally, the common shares underlying the RSUs are not eligible for distribution until the non-employee director’s service on the Board has terminated, and for non-employee director RSU grants made prior to fiscal year 2014, the share distribution date is six months after the director’s termination of service on the board. Beginning in fiscal year 2016, the Company enacted a policy that allows any non-employee directors who have Beacon equity holdings (defined as common stock and outstanding vested equity awards) with a total fair value that is greater than or equal to five times the annual Board cash retainer to elect to have any future RSU grants settle simultaneously with vesting. The following table summarizes all restricted stock unit activity for the periods presented: RSUs Outstanding Weighted-Average Grant Date Fair Value Balance as of September 30, 2018 934,023 $ 47.00 Granted 722,531 28.02 Released (375,084 ) 40.65 Canceled/Forfeited (158,112 ) 42.92 Balance as of September 30, 2019 1,123,358 $ 37.48 Vested and expected to vest after September 30, 2019 908,892 $ 39.41 During the years ended September 30, 2019, 2018, and 2017, the Company recorded stock-based compensation expense related to RSUs of $12.3 million, $12.6 million, and $10.3 million, respectively. As of September 30, 2019, there was $14.3 million of total unrecognized compensation cost related to unvested restricted stock units, which is expected to be recognized over a weighted-average period of 1.6 years. The following table summarizes additional information on RSUs for the period presented (in thousands, except share and per share amounts): Year Ended September 30, 2019 2018 2017 Weighted-average fair value of RSUs granted $ 28.02 $ 57.40 $ 47.31 Total grant date fair value of RSUs vested 16,087 6,656 4,562 Total intrinsic value of RSUs released 11,460 11,041 6,079

Income Taxes

Income Taxes	12 Months Ended
	Sep. 30, 2019
Income Tax Disclosure [Abstract]
Income Taxes	13. Income Taxes On December 22, 2017, the U.S. federal government officially signed into law the Tax Cut and Jobs Act of 2017 (“TCJA”). ASC 740, Accounting for Income Taxes, required companies to recognize the effect of tax law changes in the period of enactment even though the effective date for most provisions was for tax years beginning after December 31, 2017, or in the case of certain other provisions, January 1, 2018. The Company has fully implemented the federal TCJA provisions into its ASC 740 analysis. State conformity to the TCJA law changes have been communicated by the state and local jurisdictions; therefore, the Company has made adjustments related to the potential impact in its financial statements. The following table summarizes the components of the income tax provision (benefit) (in thousands): Year Ended September 30, 2019 2018 2017 Current: Federal 1 $ - $ (4,435 ) $ 52,718 Foreign 579 492 1,366 State 1,647 3,516 8,975 Total current taxes $ 2,226 $ (427 ) $ 63,059 Deferred: Federal $ (1,452 ) $ (35,249 ) $ (656 ) Foreign - (173 ) - State (944 ) 5,305 78 Total deferred taxes $ (2,396 ) $ (30,117 ) $ (578 ) Provision for (benefit from) income taxes $ (170 ) $ (30,544 ) $ 62,481 _____________________________ 1 The following table is a reconciliation of the statutory federal income tax rate to the Company’s effective income tax rate for the periods presented: Year Ended September 30, 2019 2018 2017 U.S. federal income taxes at statutory rate 21.0 % 24.5 % 35.0 % State income taxes, net of federal benefit (3.3 %) 5.2 % 3.9 % Share-based payments (4.7 %) (3.9 %) 0.0 % Deferred tax asset/liability remeasurement 1 0.0 % (73.5 %) 0.0 % Repatriation transition tax 1 4.3 % 1.8 % 0.0 % Non-deductible meals and entertainment (13.9 %) 2.2 % 0.6 % Other (1.8 %) (1.2 %) (1.2 %) Effective tax rate 1.6 % (44.9 %) 38.3 % _____________________________ 1 2018 includes Impact of Tax Cut and Jobs Act of 2017 Deferred income taxes reflect the tax consequences of temporary differences between the amounts of assets and liabilities for financial reporting purposes and such amounts as measured by tax law. These temporary differences are determined according to ASC 740 Income Taxes. Temporary differences that give rise to deferred tax assets and liabilities are as follows (in thousands): September 30, 2019 2018 Deferred tax assets: Deferred compensation $ 11,099 $ 11,346 Allowance for doubtful accounts 4,218 663 Accrued vacation and other 5,148 5,079 Inventory valuation 14,307 12,900 Tax loss carryforwards 1 18,272 17,271 Unrealized loss on financial derivatives 510 - Other 1,611 1,517 Total deferred tax assets $ 55,165 $ 48,776 Deferred tax liabilities: Excess tax over book depreciation and amortization $ (159,078 ) $ (155,770 ) Total deferred tax liabilities (159,078 ) (155,770 ) Net deferred income tax liabilities $ (103,913 ) $ (106,994 ) _____________________________ 1 Comprised of net operating loss, foreign tax, and alternative minimum tax carryforwards The Company acquired $135.3 million of federal and state net operating loss (“NOL”) carryforwards as part of its acquisition of RSG in fiscal year 2016. For the year ended September 30, 2019, the Company utilized $26.3 million of federal NOLs. As of September 30, 2019, the Company had a total federal NOL carryforward balance of $31.5 million, portions of which is set to expire at various dates through 2035. The Company’s non-domestic subsidiary, BRSCC, is treated as a controlled foreign corporation. BRSCC’s taxable income, which reflects all of the Company’s Canadian operations, is being taxed only in Canada and would generally be taxed in the United States only upon an actual or deemed distribution. The Company expects that BRSCC’s earnings will be indefinitely reinvested for the foreseeable future; therefore, no United States deferred tax asset or liability for the differences between the book basis and the tax basis of BRSCC has been recorded as of September 30, 2019. As of September 30, 2019, the Company’s goodwill balance on its consolidated balance sheet was $2.49 billion, of which there remains an amortizable tax basis of $1.10 billion for income tax purposes. As of September 30, 2019, there were no uncertain tax positions which, if recognized, would affect the Company’s effective tax rate. The Company’s accounting policy is to recognize any interest and penalties related to income tax matters in income tax expense in the consolidated statements of operations. The Company has operations in 50 U.S. states and 6 provinces in Canada. The Company is currently under audit in certain state and local jurisdictions for various years. These audits may involve complex issues, which may require an extended period of time to resolve. Additional taxes are reasonably possible; however, the amounts cannot be estimated at this time or would not be significant. The Company is no longer subject to U.S. federal income tax examinations for any fiscal years ended on or before September 30, 2015. For the majority of states, the Company is also no longer subject to tax examinations for any fiscal years ended on or before September 30, 2015. In Canada, the Company is no longer subject to tax examinations for any fiscal years ended on or before September 30, 2015. For the Canadian provinces, the Company is no longer subject to tax examinations for any fiscal years ended on or before September 30, 2015.

Geographic and Product Data

Geographic and Product Data	12 Months Ended
	Sep. 30, 2019
Segment Reporting [Abstract]
Geographic and Product Data	14. Geographic and Product Data The following tables summarize certain geographic information for the periods presented (in thousands): September 30, 2019 2018 Long-lived assets: U.S. $ 1,182,552 $ 1,409,742 Canada 12,373 13,224 Total long-lived assets $ 1,194,925 $ 1,422,966

Supplemental Guarantor Informat

Supplemental Guarantor Information	12 Months Ended
	Sep. 30, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Supplemental Guarantor Information	15. The 2023 Senior Notes and 2025 Senior Notes are guaranteed jointly and severally by all of the United States subsidiaries of the Company (collectively, the “Guarantor”), and not by the Canadian subsidiaries of the Company. Such guarantees are full and unconditional. Supplemental condensed consolidating financial information of the Company, including such information for the Guarantor, is presented below. The information is presented in accordance with the requirements of Rule 3-10 under the SEC’s Regulation S-X. The financial information may not necessarily be indicative of results of operations, cash flows or financial position had the non-guarantor subsidiaries operated as independent entities. Investments in subsidiaries are presented using the equity method of accounting. The principal elimination entries eliminate investments in subsidiaries and intercompany balances and transactions. Separate financial statements of the Guarantor are not provided as the consolidating financial information contained herein provides a more meaningful disclosure to allow investors to determine the nature of the assets held by, and the operations of, the combined groups. BEACON ROOFING SUPPLY, INC. Condensed Consolidating Balance Sheets (Unaudited; In thousands) September 30, 2019 Parent Guarantor Subsidiaries Non- Guarantor Subsidiaries Eliminations and Other Consolidated Assets Current assets: Cash and cash equivalents $ - $ 65,213 $ 7,074 $ - $ 72,287 Accounts receivable, net - 1,067,109 42,165 (1,140 ) 1,108,134 Inventories, net - 988,925 29,258 - 1,018,183 Prepaid expenses and other current assets 15,788 291,736 8,119 - 315,643 Total current assets 15,788 2,412,983 86,616 (1,140 ) 2,514,247 Intercompany receivable, net - 1,561,217 - (1,561,217 ) - Investments in consolidated subsidiaries 6,365,732 - - (6,365,732 ) - Deferred income taxes, net 17,123 - - (17,123 ) - Property and equipment, net 20,507 229,267 10,602 - 260,376 Goodwill - 2,461,212 29,378 - 2,490,590 Intangibles, net - 1,123,768 1,772 - 1,125,540 Other assets, net 2,059 - - - 2,059 Total assets $ 6,421,209 $ 7,788,447 $ 128,368 $ (7,945,212 ) $ 6,392,812 Liabilities and Stockholders' Equity Current liabilities: Accounts payable $ 51,142 $ 745,820 $ 27,109 $ (1,140 ) $ 822,931 Accrued expenses 80,556 504,150 14,449 - 599,155 Current portions of long-term debt/obligations 9,700 8,989 - - 18,689 Total current liabilities 141,398 1,258,959 41,558 (1,140 ) 1,440,775 Intercompany payable, net 1,523,640 - 37,577 (1,561,217 ) - Borrowings under revolving lines of credit, net - 80,961 - - 80,961 Long-term debt, net 2,494,623 - - - 2,494,623 Deferred income taxes, net - 120,643 393 (17,123 ) 103,913 Long-term obligations under equipment financing and other, net - 4,609 - - 4,609 Other long-term liabilities - 6,301 82 - 6,383 Total liabilities 4,159,661 1,471,473 79,610 (1,579,480 ) 4,131,264 Convertible preferred stock 399,195 - - - 399,195 Total stockholders' equity 1,862,353 6,316,974 48,758 (6,365,732 ) 1,862,353 Total liabilities and stockholders' equity $ 6,421,209 $ 7,788,447 $ 128,368 $ (7,945,212 ) $ 6,392,812 BEACON ROOFING SUPPLY, INC. Condensed Consolidating Balance Sheets (Unaudited; In thousands) September 30, 2018 Parent Guarantor Subsidiaries Non- Guarantor Subsidiaries Eliminations and Other Consolidated Assets Current assets: Cash and cash equivalents $ - $ 136,499 $ 1,959 $ (8,531 ) $ 129,927 Accounts receivable, net - 1,051,410 40,262 (1,139 ) 1,090,533 Inventories, net - 907,605 28,442 - 936,047 Prepaid expenses and other current assets 23,711 214,011 6,638 - 244,360 Total current assets 23,711 2,309,525 77,301 (9,670 ) 2,400,867 Intercompany receivable, net - 1,361,615 - (1,361,615 ) - Investments in consolidated subsidiaries 6,109,325 - - (6,109,325 ) - Deferred income taxes, net 22,475 - - (22,475 ) - Property and equipment, net 18,929 250,517 10,961 - 280,407 Goodwill - 2,461,725 30,054 - 2,491,779 Intangibles, net - 1,332,104 2,262 - 1,334,366 Other assets, net 1,243 - - - 1,243 Total assets $ 6,175,683 $ 7,715,486 $ 120,578 $ (7,503,085 ) $ 6,508,662 Liabilities and Stockholders' Equity Current liabilities: Accounts payable $ 24,154 $ 843,907 $ 22,482 $ (9,671 ) $ 880,872 Accrued expenses 41,448 564,331 5,760 - 611,539 Current portions of long-term debt/obligations 9,700 9,961 - - 19,661 Total current liabilities 75,302 1,418,199 28,242 (9,671 ) 1,512,072 Intercompany payable, net 1,322,156 - 39,459 (1,361,615 ) - Borrowings under revolving lines of credit, net - 89,352 3,090 - 92,442 Long-term debt, net 2,494,725 - - - 2,494,725 Deferred income taxes, net - 128,846 622 (22,474 ) 106,994 Long-term obligations under equipment financing and other, net - 13,639 - - 13,639 Other long-term liabilities - 5,207 83 - 5,290 Total liabilities 3,892,183 1,655,243 71,496 (1,393,760 ) 4,225,162 Convertible preferred stock 399,195 - - - 399,195 Total stockholders' equity 1,884,305 6,060,243 49,082 (6,109,325 ) 1,884,305 Total liabilities and stockholders' equity $ 6,175,683 $ 7,715,486 $ 120,578 $ (7,503,085 ) $ 6,508,662 BEACON ROOFING SUPPLY, INC. Condensed Consolidating Statements of Operations (Unaudited; In thousands, except share and per share amounts) Year Ended September 30, 2019 Parent Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations and Other Consolidated Net sales $ - $ 6,918,518 $ 186,642 $ - $ 7,105,160 Cost of products sold - 5,220,994 147,611 - 5,368,605 Gross profit - 1,697,524 39,031 - 1,736,555 Operating expense Selling, general and administrative 17,627 1,261,370 32,046 - 1,311,043 Depreciation 4,027 64,801 1,867 - 70,695 Amortization - 206,627 438 - 207,065 Total operating expense 21,654 1,532,798 34,351 - 1,588,803 Intercompany charges (income) (17,576 ) 17,132 444 - - Income (loss) from operations (4,078 ) 147,594 4,236 - 147,752 Interest expense, financing costs, and other 140,489 17,327 718 - 158,534 Intercompany interest expense (income) (39,670 ) 38,142 1,528 - - Income (loss) before provision for income taxes (104,897 ) 92,125 1,990 - (10,782 ) Provision for (benefit from) income taxes (116 ) (632 ) 578 - (170 ) Income (loss) before equity in net income of subsidiaries (104,781 ) 92,757 1,412 - (10,612 ) Equity in net income of subsidiaries 94,169 - - (94,169 ) - Net income (loss) $ (10,612 ) $ 92,757 $ 1,412 $ (94,169 ) $ (10,612 ) BEACON ROOFING SUPPLY, INC. Condensed Consolidating Statements of Operations (Unaudited; In thousands, except share and per share amounts) Year Ended September 30, 2018 Parent Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations and Other Consolidated Net sales $ - $ 6,239,332 $ 178,979 $ - $ 6,418,311 Cost of products sold - 4,685,616 139,374 - 4,824,990 Gross profit - 1,553,716 39,605 - 1,593,321 Operating expense Selling, general and administrative 5,909 1,147,390 33,893 - 1,187,192 Depreciation 1,989 56,598 1,731 - 60,318 Amortization - 140,664 521 - 141,185 Total operating expense 7,898 1,344,652 36,145 - 1,388,695 Intercompany charges (income) (6,734 ) 6,565 169 - - Income (loss) from operations (1,164 ) 202,499 3,291 - 204,626 Interest expense, financing costs, and other 124,169 11,648 727 - 136,544 Intercompany interest expense (income) (24,270 ) 22,738 1,532 - - Income (loss) before provision for income taxes (101,063 ) 168,113 1,032 - 68,082 Provision for (benefit from) income taxes 11,398 (42,261 ) 319 - (30,544 ) Income (loss) before equity in net income of subsidiaries (112,461 ) 210,374 713 - 98,626 Equity in net income of subsidiaries 211,087 - - (211,087 ) - Net income (loss) $ 98,626 $ 210,374 $ 713 $ (211,087 ) $ 98,626 BEACON ROOFING SUPPLY, INC. Condensed Consolidating Statements of Operations (Unaudited; In thousands, except share and per share amounts) Year Ended September 30, 2017 Parent Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations and Other Consolidated Net sales $ - $ 4,198,935 $ 177,735 $ - $ 4,376,670 Cost of products sold - 3,162,896 137,835 - 3,300,731 Gross profit - 1,036,039 39,900 - 1,075,939 Operating expense Selling, general and administrative 26,962 685,690 30,724 - 743,376 Depreciation 1,534 30,758 1,710 - 34,002 Amortization - 81,880 585 - 82,465 Total operating expense 28,496 798,328 33,019 - 859,843 Intercompany charges (income) (4,664 ) 4,342 322 - - Income (loss) from operations (23,832 ) 233,369 6,559 - 216,096 Interest expense, financing costs, and other 38,660 14,033 58 - 52,751 Intercompany interest expense (income) (24,458 ) 22,927 1,531 - - Income (loss) before provision for income taxes (38,034 ) 196,409 4,970 - 163,345 Provision for (benefit from) income taxes (3,284 ) 64,399 1,366 - 62,481 Income (loss) before equity in net income of subsidiaries (34,750 ) 132,010 3,604 - 100,864 Equity in net income of subsidiaries 135,614 - - (135,614 ) - Net income (loss) $ 100,864 $ 132,010 $ 3,604 $ (135,614 ) $ 100,864 BEACON ROOFING SUPPLY, INC. Condensed Consolidating Statements of Comprehensive Income (Unaudited; In thousands) Year Ended September 30, 2019 Parent Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations and Other Consolidated Net income (loss) $ (10,612 ) $ 92,757 $ 1,412 $ (94,169 ) $ (10,612 ) Other comprehensive income (loss): Foreign currency translation adjustment (1,734 ) - (1,734 ) 1,734 (1,734 ) Unrealized gain (loss) due to change in fair value of derivatives, net of tax (1,612 ) - (1,612 ) 1,612 (1,612 ) Total other comprehensive income (loss) (3,346 ) - (3,346 ) 3,346 (3,346 ) Comprehensive income (loss) $ (13,958 ) $ 92,757 $ (1,934 ) $ (90,823 ) $ (13,958 ) Year Ended September 30, 2018 Parent Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations and Other Consolidated Net income (loss) $ 98,626 $ 210,374 $ 713 $ (211,087 ) $ 98,626 Other comprehensive income (loss): Foreign currency translation adjustment (2,687 ) - (2,687 ) 2,687 (2,687 ) Total other comprehensive income (loss) (2,687 ) - (2,687 ) 2,687 (2,687 ) Comprehensive income (loss) $ 95,939 $ 210,374 $ (1,974 ) $ (208,400 ) $ 95,939 Year Ended September 30, 2017 Parent Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations and Other Consolidated Net income (loss) $ 100,864 $ 132,010 $ 3,604 $ (135,614 ) $ 100,864 Other comprehensive income (loss): Foreign currency translation adjustment 3,706 - 3,706 (3,706 ) 3,706 Total other comprehensive income (loss) 3,706 - 3,706 (3,706 ) 3,706 Comprehensive income (loss) $ 104,570 $ 132,010 $ 7,310 $ (139,320 ) $ 104,570 BEACON ROOFING SUPPLY, INC. Condensed Consolidating Statements of Cash Flows (Unaudited; In thousands) Year Ended September 30, 2019 Parent Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations and Other Consolidated Net cash provided by (used in) operating activities $ 6,250 $ 188,268 $ 11,339 $ 6,796 $ 212,653 Investing Activities Purchases of property and equipment (7,156 ) (48,311 ) (1,564 ) - (57,031 ) Acquisition of businesses, net - (163,973 ) - - (163,973 ) Proceeds from the sale of assets - 9,256 13 - 9,269 Intercompany activity 35,777 - - (35,777 ) - Net cash provided by (used in) investing activities 28,621 (203,028 ) (1,551 ) (35,777 ) (211,735 ) Financing Activities Borrowings under revolving lines of credit - 2,049,500 50,585 - 2,100,085 Repayments under revolving lines of credit - (2,060,396 ) (53,586 ) - (2,113,982 ) Repayments under term loan (9,700 ) - - - (9,700 ) Payment of debt issuance costs (817 ) - - - (817 ) Repayments under equipment financing facilities and other - (10,001 ) - - (10,001 ) Payment of dividends on preferred stock (24,000 ) - - - (24,000 ) Proceeds from issuance of common stock related to equity awards 3,314 - - - 3,314 Taxes paid related to net share settlement of equity awards (3,668 ) - - - (3,668 ) Intercompany activity - (35,629 ) (1,826 ) 37,455 - Net cash provided by (used in) financing activities (34,871 ) (56,526 ) (4,827 ) 37,455 (58,769 ) Effect of exchange rate changes on cash and cash equivalents - - 154 57 211 Net increase (decrease) in cash and cash equivalents - (71,286 ) 5,115 8,531 (57,640 ) Cash and cash equivalents, beginning of period - 136,499 1,959 (8,531 ) 129,927 Cash and cash equivalents, end of period $ - $ 65,213 $ 7,074 $ - $ 72,287 BEACON ROOFING SUPPLY, INC. Condensed Consolidating Statements of Cash Flows (Unaudited; In thousands) Year Ended September 30, 2018 Parent Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations and Other Consolidated Net cash provided by (used in) operating activities $ (100,302 ) $ 638,451 $ (680 ) $ 1,912 $ 539,381 Investing Activities Purchases of property and equipment (14,354 ) (29,132 ) (2,524 ) - (46,010 ) Acquisition of businesses, net (2,740,480 ) - - - (2,740,480 ) Proceeds from the sale of assets - 2,121 28 - 2,149 Intercompany activity 699,970 - - (699,970 ) - Net cash provided by (used in) investing activities (2,054,864 ) (27,011 ) (2,496 ) (699,970 ) (2,784,341 ) Financing Activities Borrowings under revolving lines of credit - 2,766,447 41,294 - 2,807,741 Repayments under revolving lines of credit - (2,666,447 ) (41,294 ) - (2,707,741 ) Borrowings under term loan 970,000 - - - 970,000 Repayments under term loan (445,850 ) - - - (445,850 ) Borrowings under senior notes 1,300,000 - - - 1,300,000 Payment of debt issuance costs (58,266 ) (7,522 ) - - (65,788 ) Repayments under equipment financing facilities and other - (11,593 ) - - (11,593 ) Proceeds from issuance of convertible preferred stock 400,000 - - - 400,000 Payment of stock issuance costs (1,279 ) - - - (1,279 ) Payment of dividends on preferred stock (12,978 ) - - - (12,978 ) Proceeds from issuance of common stock related to equity awards 7,514 - - - 7,514 Taxes paid related to net share settlement of equity awards (3,975 ) - - - (3,975 ) Intercompany activity - (705,625 ) 2,967 702,658 - Net cash provided by (used in) financing activities 2,155,166 (624,740 ) 2,967 702,658 2,236,051 Effect of exchange rate changes on cash and cash equivalents - - 586 - 586 Net increase (decrease) in cash and cash equivalents - (13,300 ) 377 4,600 (8,323 ) Cash and cash equivalents, beginning of period - 149,799 1,582 (13,131 ) 138,250 Cash and cash equivalents, end of period $ - $ 136,499 $ 1,959 $ (8,531 ) $ 129,927 BEACON ROOFING SUPPLY, INC. Condensed Consolidating Statements of Cash Flows (Unaudited; In thousands) Year Ended September 30, 2017 Parent Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations and Other Consolidated Net cash provided by (used in) operating activities $ (2,466 ) $ 313,396 $ 4,888 $ (618 ) $ 315,200 Investing Activities Purchases of property and equipment (3,517 ) (34,584 ) (1,727 ) - (39,828 ) Acquisition of businesses, net (129,390 ) - - - (129,390 ) Proceeds from the sale of assets - 2,150 83 - 2,233 Intercompany activity (203,163 ) - - 203,163 - Net cash provided by (used in) investing activities (336,070 ) (32,434 ) (1,644 ) 203,163 (166,985 ) Financing Activities Borrowings under revolving lines of credit - 2,445,084 19,044 - 2,464,128 Repayments under revolving lines of credit - (2,812,663 ) (20,567 ) - (2,833,230 ) Repayments under term loan (4,500 ) - - - (4,500 ) Payment of debt issuance costs (1,669 ) - - - (1,669 ) Repayments under equipment financing facilities and other - (10,049 ) 15 - (10,034 ) Proceeds from secondary offering of common stock 345,503 - - - 345,503 Payment of stock issuance costs (14,684 ) - - - (14,684 ) Proceeds from issuance of common stock related to equity awards 11,341 - - - 11,341 Taxes paid related to net share settlement of equity awards (392 ) - - - (392 ) Excess tax benefit from stock-based compensation 2,937 - - - 2,937 Intercompany activity - 209,018 (2,279 ) (206,739 ) - Net cash provided by (used in) financing activities 338,536 (168,610 ) (3,787 ) (206,739 ) (40,600 ) Effect of exchange rate changes on cash and cash equivalents - - (751 ) - (751 ) Net increase (decrease) in cash and cash equivalents - 112,352 (1,294 ) (4,194 ) 106,864 Cash and cash equivalents, beginning of period - 37,447 2,876 (8,937 ) 31,386 Cash and cash equivalents, end of period $ - $ 149,799 $ 1,582 $ (13,131 ) $ 138,250

Allowance for Doubtful Accounts

Allowance for Doubtful Accounts	12 Months Ended
	Sep. 30, 2019
Allowance For Doubtful Accounts [Abstract]
Allowance for Doubtful Accounts	16. Allowance for Doubtful Accounts The following table summarizes changes in the valuation of the allowance for doubtful accounts (in thousands): Year Ended September 30, Beginning Balance Charged to Operations Write-offs Ending Balance 2019 $ 17,584 $ 9,478 $ (13,967 ) $ 13,095 2018 11,829 10,948 (5,193 ) 17,584 2017 14,812 2,914 (5,897 ) 11,829 The decrease in valuation as of September 30, 2019 is primarily due to an acceleration in write-offs of aged balances that were previously reserved.

Fair Value Measurement

Fair Value Measurement	12 Months Ended
	Sep. 30, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurement	17. Fair Value Measurement As of September 30, 2019, the carrying amount of cash and cash equivalents, accounts receivable, prepaid and other current assets, accounts payable and accrued expenses approximated fair value because of the short-term nature of these instruments. The Company measures its cash equivalents at amortized cost, which approximates fair value based upon quoted market prices (Level 1). As of September 30, 2019, based upon recent trading prices (Level 2 — market approach), the fair value of the Company’s $300.0 million Senior Notes due in 2023 was $310.5 million and the fair value of the $1.30 billion Senior Notes due in 2025 was $1.28 billion. As of September 30, 2019, the fair value of the Company’s term loan and revolving asset-based line of credit approximated the amount outstanding. The Company estimates the fair value of these financing arrangements by discounting the future cash flows of each instrument using estimated market rates of debt instruments with similar maturities and credit profiles (Level 3).

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Sep. 30, 2019
Compensation And Retirement Disclosure [Abstract]
Employee Benefit Plans	18. Employee Benefit Plans The Company maintains defined contribution plans covering all full-time employees of the Company who have 90 days of service and are at least 21 years old. An eligible employee may elect to make a before-tax contribution of between 1% and 100% of his or her compensation through payroll deductions, not to exceed the annual limit set by law. The Company currently matches the first 50% of participant contributions limited to 6% of a participant’s gross compensation (maximum Company match is 3%). The combined total expense for this plan and a similar plan for Canadian employees was $11.7 million, $11.8 million, and $8.2 million for the years ended September 30, 2019, 2018, and 2017, respectively. The Company sponsors an external pension fund for certain of its foreign employees who belong to a local union. Pension contributions are made to government-sponsored social security pension plans in accordance with local legal requirements. Annual contributions were $1.0 million, $0.2 million, and $0.1 million for the years ended September 30, 2019, 2018, and 2017, respectively. The Company also participates in multi-employer defined benefit plans for which it is not the sponsor. The aggregated expense for these plans for the fiscal year ended September 30, 2019 was $2.6 million. As of September 30, 2019, the Company’s multi-employer defined benefit plans are reported to have underfunded liabilities. If the Company withdraws from participation in one of these plans, applicable law would require the Company to make a lump-sum contribution to the plan. The Company’s withdrawal liability depends on the extent of the plan’s funding of vested benefits, among other factors. In 2019, the Company’s collective bargaining agreements covering 42 employees in its Chicago, Cincinnati and Toledo branches expired. As a result of good faith collective bargaining, the Company has withdrawn from the Central States Pension Fund. The Company does not believe the final lump-sum contribution will have a material impact on operations.

Financial Derivatives

Financial Derivatives	12 Months Ended
	Sep. 30, 2019
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Financial Derivatives	19. Financial Derivatives The Company uses interest rate derivative instruments to manage the risk related to fluctuating cash flows from interest rate changes by converting a portion of its variable-rate borrowings into fixed-rate borrowings. On September 11, 2019, the Company entered into two interest rate swap agreements to manage the interest rate risk associated with the variable-rate on the 2025 Term Loan. Each swap agreement has a notional amount of $250 million. One agreement (the “5-year swap”) will expire on August 30, 2024 and swaps the thirty-day LIBOR with a fixed-rate of 1.49%. The second agreement (the “3-year swap”) will expire on August 30, 2022 and swaps the thirty-day LIBOR with a fixed-rate of 1.50%. At the inception of the swap agreements, the Company determined that both swaps qualified for cash flow hedge accounting under ASC 815. Therefore, changes in the fair value of the effective portions of the swaps, net of taxes, will be recognized in other comprehensive income each period, then reclassified into the consolidated statements of operations as a component of interest expense, financing costs, and other in the period in which the hedged transaction affects earnings. Any ineffective portions of the hedges are immediately recognized in earnings as a component of interest expense, financing costs and other. The effectiveness of the swaps will be assessed qualitatively by the Company during the lives of the hedges by a) comparing the current terms of the hedges with the related hedged debt to assure they continue to coincide and b) through an evaluation of the ability of the counterparty to the hedges to honor their obligations under the hedges. The Company performed a qualitative analysis as of September 30, 2019 and concluded that the swap agreements continue to meet the requirements under ASC 815 to qualify for cash flow hedge accounting. As of September 30, 2019, the fair value of the 3-year and 5-year swaps, net of tax, were $0.5 million and $1.1 million, respectively, both in favor of the counterparty. These amounts are included in accrued expenses in the accompanying consolidated balance sheets. The Company records any differences paid or received on its interest rate hedges to interest expense, financing costs and other. The table below presents the combined fair values, net of tax, of the interest rate derivative instruments: Location on Fair Value Liabilities as of September 30, Instrument Balance Sheet Hierarchy 2019 2018 Designated interest rate swaps Accrued expenses Level 2 $ (1,612 ) $ - The fair value of the interest rate swaps is determined through the use of a pricing model, which utilizes verifiable inputs such as market interest rates that are observable at commonly quoted intervals (generally referred to as the “LIBOR Curve”) for the full terms of the hedge agreements. These values reflect a Level 2 measurement under the applicable fair value hierarchy. The table below presents the amounts of gain (loss) on the interest rate derivative instruments recognized in other comprehensive income (OCI): Year Ended September 30, Instrument 2019 2018 2017 Designated interest rate swaps $ (1,612 ) $ - $ - The table below presents the amounts of gain (loss) on the interest rate derivative instruments recognized in interest expense, financing costs and other: Year Ended September 30, Instrument 2019 2018 2017 Designated interest rate swaps $ - $ - $ - Non-designated interest rate swaps (reclassified from accumulated other comprehensive income) $ - $ - $ (388 ) On March 28, 2013, the Company entered into an interest rate swap agreement with a notional amount of $213.8 million which expired on March 31, 2017. This agreement swapped the thirty-day LIBOR to a fixed-rate of 1.38% and had scheduled reductions of the notional amount equal to $2.8 million per quarter, effectively matching the repayment schedule under the Term Loan outstanding at that time. The Company determined this swap agreement qualified for cash flow hedge accounting under ASC 815, and therefore changes in the fair value of the effective portions of the swap, net of taxes, were recognized through other comprehensive income each period. On October 1, 2015, the Company terminated the swap agreement and settled the $2.4 million unrealized loss with the counterparty. This $2.4 million unrealized loss was recognized on a straight-line basis as interest expense from the termination date through March 31, 2017, the original expiration date of the swap agreement.

Subsequent Events

Subsequent Events	12 Months Ended
	Sep. 30, 2019
Subsequent Events [Abstract]
Subsequent Events	20. Subsequent Events On October 9, 2019, the Company, and certain subsidiaries of the Company as guarantors, executed a private offering of $300.0 million aggregate principal at a rate of 4.500% per annum (the “2026 Senior Notes”) at an issue price of 100%. The 2026 Senior Notes mature on November 15, 2026. Interest is payable on May 15 and November 15 of each year, commencing on May 15, 2020. The 2026 Senior Notes and related subsidiary guarantees were offered and sold in a private transaction exempt from the registration requirements of the Securities Act of 1933, as amended (the “Securities Act”), to qualified institutional buyers in accordance with Rule 144A under the Securities Act and to non-U.S. persons outside of the United States pursuant to Regulation S under the Securities Act. The 2026 Senior Notes and related subsidiary guarantees have not been, and will not be, registered under the Securities Act or the securities laws of any state or other jurisdiction, and may not be offered or sold in the United States absent registration or an applicable exemption from the registration requirements of the Securities Act and other applicable securities laws. On October 28, 2019, the Company used the net proceeds from the offering, together with cash on hand and available borrowings under its existing senior secured asset based revolving credit facility (the “2023 ABL”), to redeem all $300.0 million aggregate principal amount outstanding of its 6.375% senior secured notes due 2023 (the “2023 Senior Notes”) at a redemption price of 103.188% and to pay all related accrued interest, fees and expenses. The intent of the transaction was to take advantage of lower market interest rates by refinancing the existing 2023 Senior Notes with the 2026 Senior Notes. The Company has accounted for the re-finance as a debt extinguishment of the 2023 Senior Notes and an issuance of the 2026 Senior Notes. As a result, the Company will record a n estimated loss on extinguishment of $ million in the first fiscal quarter of fiscal year 2020.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All inter-company transactions have been eliminated. Certain prior period amounts have been reclassified to conform to current period presentation.
Use of Estimates	Use of Estimates The preparation of consolidated financial statements in conformity with United States generally accepted accounting principles (“GAAP”) requires management to make estimates and assumptions that affect the amounts reported in these consolidated financial statements and accompanying notes. Significant items subject to such estimates include inventories, purchase price allocations, recoverability of goodwill and intangibles, and income taxes. Actual amounts could differ from those estimates.
Fiscal Year	Fiscal Year The fiscal years presented are the years ended September 30, 2019 (“2019”), September 30, 2018 (“2018”), and September 30, 2017 (“2017”). Each of the Company’s first three quarters ends on the last day of the calendar month.
Segment Information	Segment Information Operating segments are defined as components of a business that can earn revenue and incur expenses for which discrete financial information is evaluated on a regular basis by the chief operating decision maker (“CODM”) in order to decide how to allocate resources and assess performance. The Company’s CODM, the Chief Executive Officer, reviews consolidated results of operations to make decisions, therefore the Company views its operations and manages its business as one operating segment.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers all highly liquid investments with maturities of three months or less when purchased to be cash equivalents. Cash and cash equivalents also include unsettled credit card transactions. Cash equivalents are comprised of money market funds which invest primarily in commercial paper or bonds with a rating of A-1 or better, and bank certificates of deposit.
Accounts Receivable	Accounts Receivable Accounts receivable are derived from unpaid invoiced amounts and are recorded at their net realizable value. The allowance for doubtful accounts is calculated based on actual historical write-offs and current economic factors and represents the Company’s best estimate of its credit exposure. Each month the Company reviews its receivables on a customer-by-customer basis and any balances that are deemed uncollectible are written off against the allowance after all means of collection have been exhausted and the potential for recovery is considered remote. The Company’s accounts receivable are primarily from customers in the building industry located in the United States and Canada, and no single customer represented at least 10% of the Company’s revenue during the year ended September 30, 2019 or accounts receivable as of September 30, 2019.
Concentrations of Risk	Concentrations of Risk Financial instruments that potentially subject the Company to significant concentration of credit risk consist primarily of cash, cash equivalents and accounts receivable. The Company maintains the majority of its cash and cash equivalents with one financial institution, which management believes to be financially sound and with minimal credit risk. The Company’s deposits typically exceed amounts guaranteed by the Federal Deposit Insurance Corporation.
Inventories	Inventories Inventories, consisting substantially of finished goods, are valued at the lower of cost or market (net realizable value). Cost is determined using the moving weighted-average cost method. The Company’s arrangements with vendors typically provide for rebates after it makes a special purchase and/or monthly, quarterly and/or annual rebates of a specified amount of consideration payable when a number of measures have been achieved. Annual rebates are generally related to a specified cumulative level of purchases on a calendar-year basis. The Company accounts for such rebates as a reduction of the inventory value until the product is sold, at which time such rebates reduce cost of sales in the consolidated statements of operations. Throughout the year, the Company estimates the amount of the periodic rebates based upon the expected level of purchases. The Company continually revises these estimates to reflect actual rebates earned based on actual purchase levels. Amounts due from vendors under these arrangements are included in “prepaid expenses and other current assets” in the accompanying consolidated balance sheets.
Property and Equipment	Property and Equipment Property and equipment acquired in connection with acquisitions are recorded at fair value as of the date of the acquisition and depreciated utilizing the straight-line method over the estimated remaining lives. All other additions are recorded at cost, and depreciation is computed using the straight-line method. The Company reviews the estimated useful lives of its fixed assets on an ongoing basis and the following table summarizes the estimates currently used: Asset Class Estimated Useful Life Buildings and improvements 40 years Equipment 3 to 7 years Furniture and fixtures 7 years Leasehold improvements Shorter of the estimated useful life or the term of the lease, considering renewal options expected to be exercised.
Business Combinations	Business Combinations The Company records acquisitions resulting in the consolidation of a business using the acquisition method of accounting. Under this method, the acquiring Company records the assets acquired, including intangible assets that can be identified and named, and liabilities assumed based on their estimated fair values at the date of acquisition. The Company uses an income approach to determine the fair value of acquired intangible assets, specifically the multi-period excess earnings method for customer relationships and the relief from royalty method for trade names. Various Level 3 fair value assumptions are used in the determination of these estimated fair values, including items such sales growth rates, cost synergies, customer attrition rates, discount rates, and other prospective financial information. The purchase price in excess of the fair value of the assets acquired and liabilities assumed is recorded as goodwill. Estimates associated with the accounting for acquisitions may change as additional information becomes available regarding the assets acquired and liabilities assumed. Transaction costs associated with acquisitions are expensed as incurred.
Goodwill and Intangibles	Goodwill and Intangibles On an annual basis and at interim periods when circumstances require, the Company tests the recoverability of its goodwill and indefinite-lived intangible assets. Examples of such indicators include a significant change in the business climate, unexpected competition, loss of key personnel or a decline in the Company’s market capitalization below the Company’s net book value. The Company performs impairment assessments at the reporting unit level, which is defined as an operating segment or one level below an operating segment, also known as a component. The Company currently has five components which it evaluates for aggregation by examining the distribution methods, sales mix, and operating results of each component to determine if these characteristics will be sustained over a long-term basis. For purposes of this evaluation, the Company expects its components to exhibit similar economic characteristics 3-5 years after events such as an acquisition within the Company’s core roofing business or management/business restructuring. Components that exhibit similar economic characteristics are subsequently aggregated into a single reporting unit. Based on the Company’s most recent impairment assessment performed as of August 31, 2019, it was determined that all of the Company’s components exhibited similar economic characteristics, and therefore should be aggregated into a single reporting unit (collectively, the “Reporting Unit”). To test for the recoverability of goodwill and indefinite-lived intangible assets, the Company first performs a qualitative assessment based on economic, industry and company-specific factors for all or selected reporting units to determine whether the existence of events and circumstances indicates that it is more likely than not that the goodwill or indefinite-lived intangible asset is impaired. Based on the results of the qualitative assessment, two additional steps in the impairment assessment may be required. The first step would require a comparison of each reporting unit’s fair value to the respective carrying value. If the carrying value exceeds the fair value, a second step is performed to measure the amount of impairment loss on a relative fair value basis, if any. Based on the Company’s most recent qualitative impairment assessment performed as of August 31, 2019 , the Company concluded that there were no indicators of impairment, and that therefore it was more likely than not that the fair value of the goodwill and indefinite-lived intangible assets exceeded their net carrying amount, and therefore the quantitative two-step impairment test was not required. The Company amortizes certain identifiable intangible assets that have finite lives, currently consisting of non-compete agreements, customer relationships and trade names. Non-compete agreements are amortized on a straight-line basis over the terms of the associated contractual agreements; customer relationship assets are amortized on an accelerated basis based on the expected cash flows generated by the existing customers; and trade names are amortized on an accelerated basis over a five or ten year period. Amortizable intangible assets are tested for impairment, when deemed necessary, based on undiscounted cash flows and, if impaired, are written down to fair value based on either discounted cash flows or appraised values. In connection with certain financing arrangements, the Company has debt issuance costs that are amortized over the lives of the associated financings.
Evaluation of Long-Lived Assets	Evaluation of Long-Lived Assets The Company evaluates the recoverability of its long-lived assets for impairment whenever events or circumstances indicate that the carrying amount of the assets may not be recoverable. Recoverability is measured by comparing the carrying amount of the asset to the future undiscounted cash flows the asset is expected to generate. If the asset is considered to be impaired, the amount of any impairment is measured as the difference between the carrying value and the fair value of the impaired asset.
Fair Value Measurement	Fair Value Measurement The Company applies fair value accounting for all financial assets and liabilities that are reported at fair value in the financial statements on a recurring basis. Fair value is defined as the price that would be received from selling an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. The accounting guidance establishes a defined three-tier hierarchy to classify and disclose the fair value of assets and liabilities on both the date of their initial measurement as well as all subsequent periods. The hierarchy prioritizes the inputs used to measure fair value by the lowest level of input that is available and significant to the fair value measurement. The three levels are described as follows: • Level 1 : Observable inputs. Quoted prices in active markets for identical assets and liabilities; • Level 2 : Observable inputs other than the quoted price. Includes quoted prices for similar instruments, quoted prices for identical or similar instruments in inactive markets and amounts derived from valuation models where all significant inputs are observable in active markets; and • Level 3 : Unobservable inputs. Includes amounts derived from valuation models where one or more significant inputs are unobservable and require the Company to develop relevant assumptions. The Company evaluates its financial assets and liabilities subject to fair value measurements on a recurring basis to determine the appropriate level of classification as of each reporting period.
Financial Derivatives	Financial Derivatives The Company has entered into interest rate swaps to minimize the risks and costs associated with financing activities, as well as to maintain an appropriate mix of fixed-rate and floating-rate debt. The swap agreements are contracts to exchange variable-rate for fixed-interest rate payments over the life of the agreements. The Company's derivative instruments are designated as cash flow hedges, for which the Company records the effective portions of changes in their fair value, net of tax, in other comprehensive income. The Company recognizes any ineffective portion of the hedges in the consolidated statement of operations through interest expense, financing costs and other.
Net Sales	Net Sales The Company records net sales when performance obligations with our customer are satisfied. A performance obligation is a promise to transfer a distinct good to the customer and is the unit of account. The transaction price is allocated to each distinct performance obligation and recognized as net sales when, or as, the performance obligation is satisfied. All contracts have a single performance obligation as the promise to transfer the individual good is not separately identifiable from other promises and is, therefore, not distinct. Performance obligations are satisfied at a point in time and net sales are recognized when the customer accepts the delivery of a product or takes possession of a product with rights and rewards of ownership. For goods shipped by third party carriers, the Company recognizes revenue upon shipment since the terms are generally FOB shipping point at which time control passes to the customer. The Company also arranges for certain products to be shipped directly from the manufacturer to the customer. The Company recognizes the gross revenue for these sales upon shipment as the terms are FOB shipping point at which time control passes to the customer. The Company enters into agreements with customers to offer rebates, generally based on achievement of specified sales levels and various marketing allowances that are common industry practice. Reductions to net sales for customer programs and incentive offerings, including promotions and other volume-based incentives, are estimated using the most likely amount method and recorded in the period in which the sale occurs. Provisions for early payment discounts are accrued in the same period in which the sale occurs. The Company does not have any material payment terms as payment is received shortly after the transfer of control of the products to the customer. Commissions to internal sales teams are paid to obtain contracts. As these contracts are less than one year, these costs are expensed as incurred. The Company includes shipping and handling costs billed to customers in net sales. Related costs are accounted for as fulfillment activities and are recognized as cost of products sold when control of the products transfers to the customer.
Leases	Leases The Company leases the majority of its facilities and enters into various other operating lease agreements in conducting its business. At the inception of each lease, the Company evaluates the lease agreement to determine whether the lease is an operating or capital lease. Operating lease expenses are recognized in the statements of operations on a straight-line basis over the term of the related lease. Some of the Company’s lease agreements may contain renewal options, tenant improvement allowances, rent holidays or rent escalation clauses. When such items are included in a lease agreement, the Company records a deferred rent asset or liability on the consolidated balance sheets equal to the difference between the rent expense and cash rent payments. The cost of property and equipment acquired under capital lease arrangements represents the lesser of the present value of the minimum lease payments or the fair value of the leased asset as of the inception of the lease.
Stock-Based Compensation	Stock-Based Compensation The Company applies the fair value method to recognize compensation expense for stock-based awards. Using this method, the estimated grant-date fair value of the award is recognized on a straight-line basis over the requisite service period based on the portion of the award that is expected to vest. The Company estimates forfeitures at the time of grant and revises the estimates, if necessary, in subsequent periods if actual forfeitures differ from those estimates. For awards with a performance-based vesting condition, the Company accrues stock-based compensation expense if it is probable that the performance condition will be achieved. Stock-based compensation expense for restricted stock units is measured based on the fair value of the Company’s common stock on the grant date. The Company utilizes the Black-Scholes option pricing model to estimate the grant-date fair value of option awards. The exercise price of option awards is set to equal the estimated fair value of the common stock at the date of the grant. The following weighted-average assumptions are also used to calculate the estimated fair value of option awards: • Expected volatility : The expected volatility of the Company’s shares is estimated using the historical stock price volatility over the most recent period commensurate with the estimated expected term of the awards. • Expected term : For employee stock option awards, the Company determines the weighted average expected term equal to the weighted period between the vesting period and the contract life of all outstanding options. • Dividend yield : The Company has not paid dividends and does not anticipate paying a cash dividend in the foreseeable future and, accordingly, uses an expected dividend yield of zero. • Risk-free interest rate : The Company bases the risk-free interest rate on the implied yield available on a U.S. Treasury note with a term equal to the estimated expected term of the awards.
Foreign Currency Translation	Foreign Currency Translation The Company’s operations located outside of the United States where the local currency is the functional currency are translated into U.S. dollars using the current rate method. Results of operations are translated at the average rate of exchange for the period. Assets and liabilities are translated at the closing rates on the period end date. Gains and losses on translation of these accounts are accumulated and reported as a separate component of equity and other comprehensive income (loss). Gains and losses on foreign currency transactions are recognized in the consolidated statements of operations as a component of interest expense, financing costs, and other.
Income Taxes	Income Taxes The Company accounts for income taxes using the liability method, which requires it to recognize a current tax liability or asset for current taxes payable or refundable and a deferred tax liability or asset for the estimated future tax effects of temporary differences between the financial statement and tax reporting bases of assets and liabilities to the extent that they are realizable. Deferred tax expense (benefit) results from the net change in deferred tax assets and liabilities during the year. FASB ASC Topic 740 prescribes a recognition threshold and measurement attribute for the financial statement recognition and measurement of a tax position taken or expected to be taken in a tax return. Based on this guidance, the Company analyzes its filing positions in all of the federal and state jurisdictions where it is required to file income tax returns, as well as all open tax years in these jurisdictions. Tax benefits from uncertain tax positions are recognized if it is more likely than not that the position is sustainable based solely on its technical merits.
Net Income (Loss) per Share	Net Income (Loss) per Share Basic net income (loss) per share is calculated by dividing net income (loss) attributable to common shareholders by the weighted-average number of common shares outstanding during the period, without consideration for common share equivalents or the conversion of Preferred Stock. Common share equivalents consist of the incremental common shares issuable upon the exercise of stock options and vesting of restricted stock unit awards. Diluted net income (loss) per common share is calculated by dividing net income (loss) attributable to common shareholders by the fully diluted weighted-average number of common shares outstanding during the period. Holders of Preferred Stock participate in dividends on an as-converted basis when declared on common shares. As a result, Preferred Stock is classified as a participating security and thereby requires the allocation of income that would have otherwise been available to common shareholders when calculating net income (loss) per share. Diluted net income (loss) per share is calculated by utilizing the most dilutive result of the if-converted and two-class methods. In both methods, net income (loss) attributable to common shareholders and the weighted-average common shares outstanding are adjusted to account for the impact of the assumed issuance of potential common shares that are dilutive, subject to dilution sequencing rules.
Recent Accounting Pronouncements - Adopted and Not Yet Adopted	Recent Accounting Pronouncements—Adopted In May 2014, the FASB issued ASU 2014-09, “ Revenue from Contracts with Customers In January 2017, the FASB issued ASU 2017-01, “ Business Combinations: Clarifying the Definition of a Business In March 2017, the FASB issued ASU 2017-07, " Compensation—Retirement Benefits (Topic 715), Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost In May 2017, the FASB issued ASU 2017-09, “ Scope of Modification Accounting .” This guidance is intended to provide clarity and reduce both diversity in practice and cost and complexity when applying the guidance in Compensation – Stock Compensation, to a change to the terms or conditions of a share-based payment award. This new standard is effective for annual reporting periods, and interim reporting periods contained therein, beginning after December 15, 2017. The Company adopted the standard as of October 1, 2018 and the standard did not have a material impact on the Company’s financial statements and related disclosures. In August 2017, the FASB issued ASU 2017-12, “ Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities In June 2018, the FASB issued ASU 2018-07, “ Compensation—Stock Compensation (Topic 718), Improvements to Nonemployee Share-Based Payment Accounting Recent Accounting Pronouncements—Not Yet Adopted In February 2016, the FASB issued ASU 2016-02, “ Leases In June 2016, the FASB issued ASU 2016-13, “ Financial Instruments—Credit Losses: Measurement of Credit Losses on Financial Instruments In January 2017, the FASB issued ASU 2017-04, “ Simplifying the Accounting for Goodwill Impairment In February 2018, the FASB issued ASU 2018-02, “ Income Statement—Reporting Comprehensive Income

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Summary of Property and Equipment Estimated Useful Life	All other additions are recorded at cost, and depreciation is computed using the straight-line method. The Company reviews the estimated useful lives of its fixed assets on an ongoing basis and the following table summarizes the estimates currently used: Asset Class Estimated Useful Life Buildings and improvements 40 years Equipment 3 to 7 years Furniture and fixtures 7 years Leasehold improvements Shorter of the estimated useful life or the term of the lease, considering renewal options expected to be exercised.

Acquisitions (Tables)

Acquisitions (Tables)	12 Months Ended
	Sep. 30, 2019
Business Combinations [Abstract]
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed	As of March 31, 2019, the Company had finalized the purchase accounting entries for the Allied Acquisition, detailed as follows (in thousands): January 2, 2018 January 2, 2018 (as reported at March 31, 2018) Adjustments (as adjusted at March 31, 2019) Cash $ 19,322 $ (19,153 ) $ 169 Accounts receivable 315,485 22,064 337,549 Inventory 322,705 (7,920 ) 314,785 Prepaid and other current assets 59,279 16,161 75,440 Property, plant, and equipment 139,528 (168 ) 139,360 Goodwill 1,130,635 102,145 1,232,780 Intangible assets 1,037,000 - 1,037,000 Current liabilities (271,252 ) 11,963 (259,289 ) Non-current liabilities (6,820 ) 6,097 (723 ) Total purchase price $ 2,745,882 $ 131,189 $ 2,877,071

Net Sales (Tables)

Net Sales (Tables)	12 Months Ended
	Sep. 30, 2019
Revenue From Contract With Customer [Abstract]
Summary of Net Sales by Product Line and Geography	The following table presents the Company’s net sales by product line and geography for the year ended September 30, 2019 (in thousands): Year Ended September 30, 2019 U.S. Canada Total Residential roofing products $ 3,023,266 $ 56,362 $ 3,079,628 Non-residential roofing products 1,582,757 122,421 1,705,178 Complementary building products 2,312,496 7,858 2,320,354 Total net sales $ 6,918,519 $ 186,641 $ 7,105,160

Net Income (Loss) Per Share (Ta

Net Income (Loss) Per Share (Tables)	12 Months Ended
	Sep. 30, 2019
Earnings Per Share [Abstract]
Components and Calculation of Basic and Diluted Net Income (Loss) Per Share	The following table presents the components and calculations of basic and diluted net income (loss) per share for each period presented (in thousands, except share and per share amounts): Year Ended September 30, 2019 2018 2017 Net income (loss) $ (10,612 ) $ 98,626 $ 100,864 Dividends on preferred shares 24,000 18,000 - Net income (loss) attributable to common shareholders $ (34,612 ) $ 80,626 $ 100,864 Undistributed income allocated to participating securities - (7,742 ) - Net income (loss) attributable to common shareholders - basic and diluted $ (34,612 ) $ 72,884 $ 100,864 Weighted-average common shares outstanding - basic 68,424,288 68,012,879 60,315,648 Effect of common share equivalents - 1,178,160 1,028,615 Weighted-average common shares outstanding - diluted 68,424,288 69,191,039 61,344,263 Net income (loss) per share - basic $ (0.51 ) $ 1.07 $ 1.67 Net income (loss) per share - diluted $ (0.51 ) $ 1.05 $ 1.64
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share	The following table includes the number of shares that may be dilutive common shares in the future. These shares were not included in the computation of diluted net income (loss) per share because the effect was either anti-dilutive or the requisite performance conditions were not met: Year Ended September 30, 2019 2018 2017 Stock options 1,336,259 388,731 331,681 Restricted stock units 122,278 192,151 61,890 Preferred Stock 9,694,619 7,224,483 -

Prepaid Expenses and Other Cu_2

Prepaid Expenses and Other Current Assets (Tables)	12 Months Ended
	Sep. 30, 2019
Prepaid Expenses And Other Current Assets [Abstract]
Schedule of Prepaid Expenses and Other Current Assets	The following table summarizes the significant components of prepaid expenses and other current assets (in thousands): September 30, 2019 2018 Vendor rebates $ 262,876 $ 199,725 Other 52,767 44,635 Total prepaid expenses and other current assets $ 315,643 $ 244,360

Property and Equipment (Tables)

Property and Equipment (Tables)	12 Months Ended
	Sep. 30, 2019
Property Plant And Equipment [Abstract]
Property and Equipment, net	The following table provides a detailed breakout of property and equipment, by type (in thousands): September 30, 2019 2018 Land and buildings $ 83,373 $ 82,991 Equipment 448,072 419,385 Furniture and fixtures 39,986 34,901 Total property and equipment 571,431 537,277 Accumulated depreciation (311,055 ) (256,870 ) Total property and equipment, net $ 260,376 $ 280,407

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	12 Months Ended
	Sep. 30, 2019
Goodwill And Intangible Assets Disclosure [Abstract]
Summary of Changes in goodwill	The following table sets forth the change in the carrying amount of goodwill during the years ended September 30, 2019 and 2018, respectively (in thousands): Balance as of September 30, 2017 $ 1,251,986 Acquisitions 1,240,913 Translation and other adjustments (1,120 ) Balance as of September 30, 2018 $ 2,491,779 Balance as of September 30, 2018 $ 2,491,779 Acquisitions 1 (513 ) Translation and other adjustments (676 ) Balance as of September 30, 2019 $ 2,490,590 ____________________________ 1 Reflects purchase accounting adjustments related to fiscal year 2018 acquisition of Atlas Supply, Inc. (see Note 3 for further discussion).
Summary of Intangible Assets	The following table summarizes intangible assets by category (in thousands, except time period amounts): September 30, Weighted- Average Remaining Life 1 2019 2018 (Years) Amortizable intangible assets: Non-compete agreements $ 2,824 $ 2,824 2.49 Customer relationships 1,530,970 1,530,565 17.65 Trademarks 10,500 10,500 6.92 Beneficial lease arrangements 8,060 8,060 3.59 Total amortizable intangible assets 1,552,354 1,551,949 Accumulated amortization (619,864 ) (410,633 ) Total amortizable intangible assets, net $ 932,490 $ 1,141,316 Indefinite lived trademarks 193,050 193,050 Total intangibles, net $ 1,125,540 $ 1,334,366 1
Summary of Estimated Future Amortization	The following table summarizes the estimated future amortization expense for intangible assets (in thousands): Year Ending September 30, 2020 $ 179,549 2021 149,980 2022 121,431 2023 97,522 2024 78,873 Thereafter 305,135 Total future amortization expense $ 932,490

Financing Arrangements (Tables)

Financing Arrangements (Tables)	12 Months Ended
	Sep. 30, 2019
Debt Disclosure [Abstract]
Schedule of Long-term Debt Instruments	The following table summarizes all financing arrangements from the respective periods presented (in thousands): September 30, 2019 2018 Revolving Lines of Credit 2023 ABL: U.S. Revolver, expires January 2023 1 $ 80,961 $ 89,352 Canada Revolver, expires January 2023 2 - 3,090 Current portion - - Borrowings under revolving lines of credit, net $ 80,961 $ 92,442 Long-term Debt, net Term Loans: Term Loan, matures January 2025 3 $ 926,535 $ 930,726 Current portion (9,700 ) (9,700 ) Long-term borrowings under term loans 916,835 921,026 Senior Notes: Senior Notes, mature October 2023 4 294,886 293,607 Senior Notes, mature November 2025 5 1,282,902 1,280,092 Current portion - - Long-term borrowings under senior notes 1,577,788 1,573,699 Long-term debt, net $ 2,494,623 $ 2,494,725 Equipment Financing Facilities and Other Equipment financing facilities, various maturities through September 2021 6 $ 6,885 $ 11,222 Capital lease obligations, various maturities through November 2021 7 6,713 12,378 Current portion (8,989 ) (9,961 ) Long-term obligations under equipment financing and other, net $ 4,609 $ 13,639 ____________________________________________________________ 1 2 3 4 5 6 7
Schedule of Maturities of Long-term Debt	Annual principal payments for all outstanding financing arrangements for each of the next five years and thereafter are as follows (in thousands): Year Ending September 30, 2023 ABL 2025 Term Loan Senior Notes 1 Equipment Financing and Other Total 2020 $ - $ 9,700 $ - $ 8,989 $ 18,689 2021 - 9,700 - 4,367 14,067 2022 - 9,700 - 213 9,913 2023 89,104 9,700 300,000 29 398,833 2024 - 9,700 - - 9,700 Thereafter - 906,950 1,300,000 - 2,206,950 Total debt 89,104 955,450 1,600,000 13,598 2,658,152 Unamortized debt issuance costs (8,143 ) (28,915 ) (22,212 ) - (59,270 ) Total long-term debt $ 80,961 $ 926,535 $ 1,577,788 $ 13,598 $ 2,598,882 1

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Sep. 30, 2019
Commitments And Contingencies Disclosure [Abstract]
Schedule of Minimum Rental Commitments under Non-cancelable Operating Leases	At September 30, 2019, the minimum rental commitments under all non-cancelable operating leases with initial or remaining terms of more than one year were as follows (in thousands): Year Ending September 30, 2020 $ 110,858 2021 103,185 2022 88,086 2023 70,839 2024 54,185 Thereafter 100,256 Total minimum lease payments $ 527,409

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Income (Loss) (Tables)	12 Months Ended
	Sep. 30, 2019
Equity [Abstract]
Reclassification out of Accumulated Other Comprehensive Income	The following table summarizes the components of and changes in accumulated other comprehensive loss (in thousands): Foreign Derivative Accumulated Other Currency Translation Financial Instruments Comprehensive Loss Balance as of September 30, 2016 $ (18,269 ) $ (388 ) $ (18,657 ) Other comprehensive loss before reclassifications 3,706 - 3,706 Reclassifications out of other comprehensive loss - 388 388 Balance as of September 30, 2017 $ (14,563 ) $ - $ (14,563 ) Other comprehensive income before reclassifications (2,687 ) - (2,687 ) Reclassifications out of other comprehensive loss - - - Balance as of September 30, 2018 $ (17,250 ) $ - $ (17,250 ) Other comprehensive income before reclassifications (1,734 ) (1,612 ) (3,346 ) Reclassifications out of other comprehensive loss - - - Balance as of September 30, 2019 $ (18,984 ) $ (1,612 ) $ (20,596 )

Stock-based Compensation (Table

Stock-based Compensation (Tables)	12 Months Ended
	Sep. 30, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Fair Values of Options, Black-Scholes Option-Pricing Model, Weighted-Average Assumptions	The fair values of the options granted for the year ended September 30, 2019 were estimated on the dates of grants using the Black-Scholes option-pricing model with the following weighted-average assumptions: Year Ended September 30, 2019 2018 2017 Risk-free interest rate 2.86 % 2.10 % 1.97 % Expected volatility 29.68 % 26.43 % 28.83 % Expected life (in years) 5.22 5.46 5.30 Dividend yield - - -
Stock Options Outstanding and Activity During the Period	The following table summarizes all stock option activity for the periods presented (in thousands, except share, per share, and time period amounts): Options Outstanding Weighted- Average Exercise Price Weighted- Average Remaining Contractual Term (Years) Aggregate Intrinsic Value 1 Balance as of September 30, 2018 1,969,037 $ 33.08 5.7 $ 14,088 Granted 674,015 27.67 Exercised (183,347 ) 18.08 Canceled/Forfeited (117,108 ) 35.18 Expired (3,108 ) 26.74 Balance as of September 30, 2019 2,339,489 $ 32.61 6.1 $ 12,034 Vested and expected to vest after September 30, 2019 2,305,869 $ 32.62 6.1 $ 11,870 Exercisable as of September 30, 2019 1,484,158 $ 31.54 4.5 $ 8,343 ___________________________________________________________________________ 1
Stock Option Grants, Vesting, and Exercises	The following table summarizes additional information on stock options for the periods presented (in thousands, except per share amounts): Year Ended September 30, 2019 2018 2017 Weighted-average fair value of stock options granted $ 8.91 $ 15.86 $ 14.21 Total grant date fair value of stock options vested 3,850 4,208 5,541 Total intrinsic value of stock options exercised 2,849 9,645 10,941
Restricted Shares and Units Outstanding and Activity During the Period	The following table summarizes all restricted stock unit activity for the periods presented: RSUs Outstanding Weighted-Average Grant Date Fair Value Balance as of September 30, 2018 934,023 $ 47.00 Granted 722,531 28.02 Released (375,084 ) 40.65 Canceled/Forfeited (158,112 ) 42.92 Balance as of September 30, 2019 1,123,358 $ 37.48 Vested and expected to vest after September 30, 2019 908,892 $ 39.41
Schedule Of Restricted Stock Units Additional Information	The following table summarizes additional information on RSUs for the period presented (in thousands, except share and per share amounts): Year Ended September 30, 2019 2018 2017 Weighted-average fair value of RSUs granted $ 28.02 $ 57.40 $ 47.31 Total grant date fair value of RSUs vested 16,087 6,656 4,562 Total intrinsic value of RSUs released 11,460 11,041 6,079

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Sep. 30, 2019
Income Tax Disclosure [Abstract]
Schedule Of Income Tax Provision (Benefit)	The following table summarizes the components of the income tax provision (benefit) (in thousands): Year Ended September 30, 2019 2018 2017 Current: Federal 1 $ - $ (4,435 ) $ 52,718 Foreign 579 492 1,366 State 1,647 3,516 8,975 Total current taxes $ 2,226 $ (427 ) $ 63,059 Deferred: Federal $ (1,452 ) $ (35,249 ) $ (656 ) Foreign - (173 ) - State (944 ) 5,305 78 Total deferred taxes $ (2,396 ) $ (30,117 ) $ (578 ) Provision for (benefit from) income taxes $ (170 ) $ (30,544 ) $ 62,481 _____________________________ 1
Principal Reason for the Difference Between Effective Income Tax Rate and the Statutory Federal Income	The following table is a reconciliation of the statutory federal income tax rate to the Company’s effective income tax rate for the periods presented: Year Ended September 30, 2019 2018 2017 U.S. federal income taxes at statutory rate 21.0 % 24.5 % 35.0 % State income taxes, net of federal benefit (3.3 %) 5.2 % 3.9 % Share-based payments (4.7 %) (3.9 %) 0.0 % Deferred tax asset/liability remeasurement 1 0.0 % (73.5 %) 0.0 % Repatriation transition tax 1 4.3 % 1.8 % 0.0 % Non-deductible meals and entertainment (13.9 %) 2.2 % 0.6 % Other (1.8 %) (1.2 %) (1.2 %) Effective tax rate 1.6 % (44.9 %) 38.3 % _____________________________ 1 2018 includes Impact of Tax Cut and Jobs Act of 2017
Components of the Company's Deferred Taxes	temporary differences are determined according to ASC 740 Income Taxes. Temporary differences that give rise to deferred tax assets and liabilities are as follows (in thousands): September 30, 2019 2018 Deferred tax assets: Deferred compensation $ 11,099 $ 11,346 Allowance for doubtful accounts 4,218 663 Accrued vacation and other 5,148 5,079 Inventory valuation 14,307 12,900 Tax loss carryforwards 1 18,272 17,271 Unrealized loss on financial derivatives 510 - Other 1,611 1,517 Total deferred tax assets $ 55,165 $ 48,776 Deferred tax liabilities: Excess tax over book depreciation and amortization $ (159,078 ) $ (155,770 ) Total deferred tax liabilities (159,078 ) (155,770 ) Net deferred income tax liabilities $ (103,913 ) $ (106,994 ) _____________________________ 1 Comprised of net operating loss, foreign tax, and alternative minimum tax carryforwards

Geographic and Product Data (Ta

Geographic and Product Data (Tables)	12 Months Ended
	Sep. 30, 2019
Segment Reporting [Abstract]
Schedule of Geographic Information	The following tables summarize certain geographic information for the periods presented (in thousands): September 30, 2019 2018 Long-lived assets: U.S. $ 1,182,552 $ 1,409,742 Canada 12,373 13,224 Total long-lived assets $ 1,194,925 $ 1,422,966

Supplemental Guarantor Inform_2

Supplemental Guarantor Information (Tables)	12 Months Ended
	Sep. 30, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Condensed Consolidating Balance Sheets	BEACON ROOFING SUPPLY, INC. Condensed Consolidating Balance Sheets (Unaudited; In thousands) September 30, 2019 Parent Guarantor Subsidiaries Non- Guarantor Subsidiaries Eliminations and Other Consolidated Assets Current assets: Cash and cash equivalents $ - $ 65,213 $ 7,074 $ - $ 72,287 Accounts receivable, net - 1,067,109 42,165 (1,140 ) 1,108,134 Inventories, net - 988,925 29,258 - 1,018,183 Prepaid expenses and other current assets 15,788 291,736 8,119 - 315,643 Total current assets 15,788 2,412,983 86,616 (1,140 ) 2,514,247 Intercompany receivable, net - 1,561,217 - (1,561,217 ) - Investments in consolidated subsidiaries 6,365,732 - - (6,365,732 ) - Deferred income taxes, net 17,123 - - (17,123 ) - Property and equipment, net 20,507 229,267 10,602 - 260,376 Goodwill - 2,461,212 29,378 - 2,490,590 Intangibles, net - 1,123,768 1,772 - 1,125,540 Other assets, net 2,059 - - - 2,059 Total assets $ 6,421,209 $ 7,788,447 $ 128,368 $ (7,945,212 ) $ 6,392,812 Liabilities and Stockholders' Equity Current liabilities: Accounts payable $ 51,142 $ 745,820 $ 27,109 $ (1,140 ) $ 822,931 Accrued expenses 80,556 504,150 14,449 - 599,155 Current portions of long-term debt/obligations 9,700 8,989 - - 18,689 Total current liabilities 141,398 1,258,959 41,558 (1,140 ) 1,440,775 Intercompany payable, net 1,523,640 - 37,577 (1,561,217 ) - Borrowings under revolving lines of credit, net - 80,961 - - 80,961 Long-term debt, net 2,494,623 - - - 2,494,623 Deferred income taxes, net - 120,643 393 (17,123 ) 103,913 Long-term obligations under equipment financing and other, net - 4,609 - - 4,609 Other long-term liabilities - 6,301 82 - 6,383 Total liabilities 4,159,661 1,471,473 79,610 (1,579,480 ) 4,131,264 Convertible preferred stock 399,195 - - - 399,195 Total stockholders' equity 1,862,353 6,316,974 48,758 (6,365,732 ) 1,862,353 Total liabilities and stockholders' equity $ 6,421,209 $ 7,788,447 $ 128,368 $ (7,945,212 ) $ 6,392,812 BEACON ROOFING SUPPLY, INC. Condensed Consolidating Balance Sheets (Unaudited; In thousands) September 30, 2018 Parent Guarantor Subsidiaries Non- Guarantor Subsidiaries Eliminations and Other Consolidated Assets Current assets: Cash and cash equivalents $ - $ 136,499 $ 1,959 $ (8,531 ) $ 129,927 Accounts receivable, net - 1,051,410 40,262 (1,139 ) 1,090,533 Inventories, net - 907,605 28,442 - 936,047 Prepaid expenses and other current assets 23,711 214,011 6,638 - 244,360 Total current assets 23,711 2,309,525 77,301 (9,670 ) 2,400,867 Intercompany receivable, net - 1,361,615 - (1,361,615 ) - Investments in consolidated subsidiaries 6,109,325 - - (6,109,325 ) - Deferred income taxes, net 22,475 - - (22,475 ) - Property and equipment, net 18,929 250,517 10,961 - 280,407 Goodwill - 2,461,725 30,054 - 2,491,779 Intangibles, net - 1,332,104 2,262 - 1,334,366 Other assets, net 1,243 - - - 1,243 Total assets $ 6,175,683 $ 7,715,486 $ 120,578 $ (7,503,085 ) $ 6,508,662 Liabilities and Stockholders' Equity Current liabilities: Accounts payable $ 24,154 $ 843,907 $ 22,482 $ (9,671 ) $ 880,872 Accrued expenses 41,448 564,331 5,760 - 611,539 Current portions of long-term debt/obligations 9,700 9,961 - - 19,661 Total current liabilities 75,302 1,418,199 28,242 (9,671 ) 1,512,072 Intercompany payable, net 1,322,156 - 39,459 (1,361,615 ) - Borrowings under revolving lines of credit, net - 89,352 3,090 - 92,442 Long-term debt, net 2,494,725 - - - 2,494,725 Deferred income taxes, net - 128,846 622 (22,474 ) 106,994 Long-term obligations under equipment financing and other, net - 13,639 - - 13,639 Other long-term liabilities - 5,207 83 - 5,290 Total liabilities 3,892,183 1,655,243 71,496 (1,393,760 ) 4,225,162 Convertible preferred stock 399,195 - - - 399,195 Total stockholders' equity 1,884,305 6,060,243 49,082 (6,109,325 ) 1,884,305 Total liabilities and stockholders' equity $ 6,175,683 $ 7,715,486 $ 120,578 $ (7,503,085 ) $ 6,508,662
Condensed Consolidating Statements of Operations	BEACON ROOFING SUPPLY, INC. Condensed Consolidating Statements of Operations (Unaudited; In thousands, except share and per share amounts) Year Ended September 30, 2019 Parent Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations and Other Consolidated Net sales $ - $ 6,918,518 $ 186,642 $ - $ 7,105,160 Cost of products sold - 5,220,994 147,611 - 5,368,605 Gross profit - 1,697,524 39,031 - 1,736,555 Operating expense Selling, general and administrative 17,627 1,261,370 32,046 - 1,311,043 Depreciation 4,027 64,801 1,867 - 70,695 Amortization - 206,627 438 - 207,065 Total operating expense 21,654 1,532,798 34,351 - 1,588,803 Intercompany charges (income) (17,576 ) 17,132 444 - - Income (loss) from operations (4,078 ) 147,594 4,236 - 147,752 Interest expense, financing costs, and other 140,489 17,327 718 - 158,534 Intercompany interest expense (income) (39,670 ) 38,142 1,528 - - Income (loss) before provision for income taxes (104,897 ) 92,125 1,990 - (10,782 ) Provision for (benefit from) income taxes (116 ) (632 ) 578 - (170 ) Income (loss) before equity in net income of subsidiaries (104,781 ) 92,757 1,412 - (10,612 ) Equity in net income of subsidiaries 94,169 - - (94,169 ) - Net income (loss) $ (10,612 ) $ 92,757 $ 1,412 $ (94,169 ) $ (10,612 ) BEACON ROOFING SUPPLY, INC. Condensed Consolidating Statements of Operations (Unaudited; In thousands, except share and per share amounts) Year Ended September 30, 2018 Parent Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations and Other Consolidated Net sales $ - $ 6,239,332 $ 178,979 $ - $ 6,418,311 Cost of products sold - 4,685,616 139,374 - 4,824,990 Gross profit - 1,553,716 39,605 - 1,593,321 Operating expense Selling, general and administrative 5,909 1,147,390 33,893 - 1,187,192 Depreciation 1,989 56,598 1,731 - 60,318 Amortization - 140,664 521 - 141,185 Total operating expense 7,898 1,344,652 36,145 - 1,388,695 Intercompany charges (income) (6,734 ) 6,565 169 - - Income (loss) from operations (1,164 ) 202,499 3,291 - 204,626 Interest expense, financing costs, and other 124,169 11,648 727 - 136,544 Intercompany interest expense (income) (24,270 ) 22,738 1,532 - - Income (loss) before provision for income taxes (101,063 ) 168,113 1,032 - 68,082 Provision for (benefit from) income taxes 11,398 (42,261 ) 319 - (30,544 ) Income (loss) before equity in net income of subsidiaries (112,461 ) 210,374 713 - 98,626 Equity in net income of subsidiaries 211,087 - - (211,087 ) - Net income (loss) $ 98,626 $ 210,374 $ 713 $ (211,087 ) $ 98,626 BEACON ROOFING SUPPLY, INC. Condensed Consolidating Statements of Operations (Unaudited; In thousands, except share and per share amounts) Year Ended September 30, 2017 Parent Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations and Other Consolidated Net sales $ - $ 4,198,935 $ 177,735 $ - $ 4,376,670 Cost of products sold - 3,162,896 137,835 - 3,300,731 Gross profit - 1,036,039 39,900 - 1,075,939 Operating expense Selling, general and administrative 26,962 685,690 30,724 - 743,376 Depreciation 1,534 30,758 1,710 - 34,002 Amortization - 81,880 585 - 82,465 Total operating expense 28,496 798,328 33,019 - 859,843 Intercompany charges (income) (4,664 ) 4,342 322 - - Income (loss) from operations (23,832 ) 233,369 6,559 - 216,096 Interest expense, financing costs, and other 38,660 14,033 58 - 52,751 Intercompany interest expense (income) (24,458 ) 22,927 1,531 - - Income (loss) before provision for income taxes (38,034 ) 196,409 4,970 - 163,345 Provision for (benefit from) income taxes (3,284 ) 64,399 1,366 - 62,481 Income (loss) before equity in net income of subsidiaries (34,750 ) 132,010 3,604 - 100,864 Equity in net income of subsidiaries 135,614 - - (135,614 ) - Net income (loss) $ 100,864 $ 132,010 $ 3,604 $ (135,614 ) $ 100,864
Condensed Consolidating Statements of Comprehensive Income	BEACON ROOFING SUPPLY, INC. Condensed Consolidating Statements of Comprehensive Income (Unaudited; In thousands) Year Ended September 30, 2019 Parent Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations and Other Consolidated Net income (loss) $ (10,612 ) $ 92,757 $ 1,412 $ (94,169 ) $ (10,612 ) Other comprehensive income (loss): Foreign currency translation adjustment (1,734 ) - (1,734 ) 1,734 (1,734 ) Unrealized gain (loss) due to change in fair value of derivatives, net of tax (1,612 ) - (1,612 ) 1,612 (1,612 ) Total other comprehensive income (loss) (3,346 ) - (3,346 ) 3,346 (3,346 ) Comprehensive income (loss) $ (13,958 ) $ 92,757 $ (1,934 ) $ (90,823 ) $ (13,958 ) Year Ended September 30, 2018 Parent Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations and Other Consolidated Net income (loss) $ 98,626 $ 210,374 $ 713 $ (211,087 ) $ 98,626 Other comprehensive income (loss): Foreign currency translation adjustment (2,687 ) - (2,687 ) 2,687 (2,687 ) Total other comprehensive income (loss) (2,687 ) - (2,687 ) 2,687 (2,687 ) Comprehensive income (loss) $ 95,939 $ 210,374 $ (1,974 ) $ (208,400 ) $ 95,939 Year Ended September 30, 2017 Parent Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations and Other Consolidated Net income (loss) $ 100,864 $ 132,010 $ 3,604 $ (135,614 ) $ 100,864 Other comprehensive income (loss): Foreign currency translation adjustment 3,706 - 3,706 (3,706 ) 3,706 Total other comprehensive income (loss) 3,706 - 3,706 (3,706 ) 3,706 Comprehensive income (loss) $ 104,570 $ 132,010 $ 7,310 $ (139,320 ) $ 104,570
Condensed Consolidating Statements of Cash Flows	BEACON ROOFING SUPPLY, INC. Condensed Consolidating Statements of Cash Flows (Unaudited; In thousands) Year Ended September 30, 2019 Parent Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations and Other Consolidated Net cash provided by (used in) operating activities $ 6,250 $ 188,268 $ 11,339 $ 6,796 $ 212,653 Investing Activities Purchases of property and equipment (7,156 ) (48,311 ) (1,564 ) - (57,031 ) Acquisition of businesses, net - (163,973 ) - - (163,973 ) Proceeds from the sale of assets - 9,256 13 - 9,269 Intercompany activity 35,777 - - (35,777 ) - Net cash provided by (used in) investing activities 28,621 (203,028 ) (1,551 ) (35,777 ) (211,735 ) Financing Activities Borrowings under revolving lines of credit - 2,049,500 50,585 - 2,100,085 Repayments under revolving lines of credit - (2,060,396 ) (53,586 ) - (2,113,982 ) Repayments under term loan (9,700 ) - - - (9,700 ) Payment of debt issuance costs (817 ) - - - (817 ) Repayments under equipment financing facilities and other - (10,001 ) - - (10,001 ) Payment of dividends on preferred stock (24,000 ) - - - (24,000 ) Proceeds from issuance of common stock related to equity awards 3,314 - - - 3,314 Taxes paid related to net share settlement of equity awards (3,668 ) - - - (3,668 ) Intercompany activity - (35,629 ) (1,826 ) 37,455 - Net cash provided by (used in) financing activities (34,871 ) (56,526 ) (4,827 ) 37,455 (58,769 ) Effect of exchange rate changes on cash and cash equivalents - - 154 57 211 Net increase (decrease) in cash and cash equivalents - (71,286 ) 5,115 8,531 (57,640 ) Cash and cash equivalents, beginning of period - 136,499 1,959 (8,531 ) 129,927 Cash and cash equivalents, end of period $ - $ 65,213 $ 7,074 $ - $ 72,287 BEACON ROOFING SUPPLY, INC. Condensed Consolidating Statements of Cash Flows (Unaudited; In thousands) Year Ended September 30, 2018 Parent Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations and Other Consolidated Net cash provided by (used in) operating activities $ (100,302 ) $ 638,451 $ (680 ) $ 1,912 $ 539,381 Investing Activities Purchases of property and equipment (14,354 ) (29,132 ) (2,524 ) - (46,010 ) Acquisition of businesses, net (2,740,480 ) - - - (2,740,480 ) Proceeds from the sale of assets - 2,121 28 - 2,149 Intercompany activity 699,970 - - (699,970 ) - Net cash provided by (used in) investing activities (2,054,864 ) (27,011 ) (2,496 ) (699,970 ) (2,784,341 ) Financing Activities Borrowings under revolving lines of credit - 2,766,447 41,294 - 2,807,741 Repayments under revolving lines of credit - (2,666,447 ) (41,294 ) - (2,707,741 ) Borrowings under term loan 970,000 - - - 970,000 Repayments under term loan (445,850 ) - - - (445,850 ) Borrowings under senior notes 1,300,000 - - - 1,300,000 Payment of debt issuance costs (58,266 ) (7,522 ) - - (65,788 ) Repayments under equipment financing facilities and other - (11,593 ) - - (11,593 ) Proceeds from issuance of convertible preferred stock 400,000 - - - 400,000 Payment of stock issuance costs (1,279 ) - - - (1,279 ) Payment of dividends on preferred stock (12,978 ) - - - (12,978 ) Proceeds from issuance of common stock related to equity awards 7,514 - - - 7,514 Taxes paid related to net share settlement of equity awards (3,975 ) - - - (3,975 ) Intercompany activity - (705,625 ) 2,967 702,658 - Net cash provided by (used in) financing activities 2,155,166 (624,740 ) 2,967 702,658 2,236,051 Effect of exchange rate changes on cash and cash equivalents - - 586 - 586 Net increase (decrease) in cash and cash equivalents - (13,300 ) 377 4,600 (8,323 ) Cash and cash equivalents, beginning of period - 149,799 1,582 (13,131 ) 138,250 Cash and cash equivalents, end of period $ - $ 136,499 $ 1,959 $ (8,531 ) $ 129,927 BEACON ROOFING SUPPLY, INC. Condensed Consolidating Statements of Cash Flows (Unaudited; In thousands) Year Ended September 30, 2017 Parent Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations and Other Consolidated Net cash provided by (used in) operating activities $ (2,466 ) $ 313,396 $ 4,888 $ (618 ) $ 315,200 Investing Activities Purchases of property and equipment (3,517 ) (34,584 ) (1,727 ) - (39,828 ) Acquisition of businesses, net (129,390 ) - - - (129,390 ) Proceeds from the sale of assets - 2,150 83 - 2,233 Intercompany activity (203,163 ) - - 203,163 - Net cash provided by (used in) investing activities (336,070 ) (32,434 ) (1,644 ) 203,163 (166,985 ) Financing Activities Borrowings under revolving lines of credit - 2,445,084 19,044 - 2,464,128 Repayments under revolving lines of credit - (2,812,663 ) (20,567 ) - (2,833,230 ) Repayments under term loan (4,500 ) - - - (4,500 ) Payment of debt issuance costs (1,669 ) - - - (1,669 ) Repayments under equipment financing facilities and other - (10,049 ) 15 - (10,034 ) Proceeds from secondary offering of common stock 345,503 - - - 345,503 Payment of stock issuance costs (14,684 ) - - - (14,684 ) Proceeds from issuance of common stock related to equity awards 11,341 - - - 11,341 Taxes paid related to net share settlement of equity awards (392 ) - - - (392 ) Excess tax benefit from stock-based compensation 2,937 - - - 2,937 Intercompany activity - 209,018 (2,279 ) (206,739 ) - Net cash provided by (used in) financing activities 338,536 (168,610 ) (3,787 ) (206,739 ) (40,600 ) Effect of exchange rate changes on cash and cash equivalents - - (751 ) - (751 ) Net increase (decrease) in cash and cash equivalents - 112,352 (1,294 ) (4,194 ) 106,864 Cash and cash equivalents, beginning of period - 37,447 2,876 (8,937 ) 31,386 Cash and cash equivalents, end of period $ - $ 149,799 $ 1,582 $ (13,131 ) $ 138,250

Allowance for Doubtful Accoun_2

Allowance for Doubtful Accounts (Tables)	12 Months Ended
	Sep. 30, 2019
Allowance For Doubtful Accounts [Abstract]
Allowance for Doubtful Accounts	The following table summarizes changes in the valuation of the allowance for doubtful accounts (in thousands): Year Ended September 30, Beginning Balance Charged to Operations Write-offs Ending Balance 2019 $ 17,584 $ 9,478 $ (13,967 ) $ 13,095 2018 11,829 10,948 (5,193 ) 17,584 2017 14,812 2,914 (5,897 ) 11,829

Financial Derivatives (Tables)

Financial Derivatives (Tables)	12 Months Ended
	Sep. 30, 2019
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Summary of Combined Fair Values, Net of Tax of Interest Rate Derivative Instruments	The Company records any differences paid or received on its interest rate hedges to interest expense, financing costs and other. The table below presents the combined fair values, net of tax, of the interest rate derivative instruments: Location on Fair Value Liabilities as of September 30, Instrument Balance Sheet Hierarchy 2019 2018 Designated interest rate swaps Accrued expenses Level 2 $ (1,612 ) $ -
Summary of Amounts of Gain (Loss) on Interest Rate Derivative Instruments Recognized in Other Comprehensive Income (OCI)	The table below presents the amounts of gain (loss) on the interest rate derivative instruments recognized in other comprehensive income (OCI): Year Ended September 30, Instrument 2019 2018 2017 Designated interest rate swaps $ (1,612 ) $ - $ -
Summary of Amounts of Gain (Loss) on Interest Rate Derivative Instruments Recognized in Interest Expense, Financing costs and Other	The table below presents the amounts of gain (loss) on the interest rate derivative instruments recognized in interest expense, financing costs and other: Year Ended September 30, Instrument 2019 2018 2017 Designated interest rate swaps $ - $ - $ - Non-designated interest rate swaps (reclassified from accumulated other comprehensive income) $ - $ - $ (388 )

Company Overview - Additional I

Company Overview - Additional Information (Detail)	12 Months Ended
	Sep. 30, 2019StateProvince
Company Overview [Line Items]
Date of incorporation	Aug. 22, 1997
U.S. [Member]
Company Overview [Line Items]
Number of states in which entity operates | State	50
Canada [Member]
Company Overview [Line Items]
Number of provinces in which entity operates | Province	6

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Detail) $ in Millions	12 Months Ended
	Sep. 30, 2019USD ($)SegmentCustomer	Sep. 30, 2018	Sep. 30, 2017
Significant Accounting Policies [Line Items]
Number of operating segments | Segment	1
Number of customers, with at least 10% of revenue | Customer	0
Number of customers, with at least 10% of accounts receivable | Customer	0
Expected dividend yield	0.00%	0.00%	0.00%
Trade Names [Member]
Significant Accounting Policies [Line Items]
Finite-lived intangible assets, amortization method	accelerated basis over a five or ten year period
Minimum [Member]
Significant Accounting Policies [Line Items]
Amortization period	5 years
Minimum [Member] | Accounting Standards Update 2016-02 [Member]
Significant Accounting Policies [Line Items]
Operating lease right of use assets	$ 480
Operating lease liabilities	$ 470
Minimum [Member] | Trade Names [Member]
Significant Accounting Policies [Line Items]
Amortization period	5 years
Maximum [Member]
Significant Accounting Policies [Line Items]
Amortization period	20 years
Maximum [Member] | Accounting Standards Update 2016-02 [Member]
Significant Accounting Policies [Line Items]
Operating lease right of use assets	$ 500
Operating lease liabilities	$ 490
Maximum [Member] | Trade Names [Member]
Significant Accounting Policies [Line Items]
Amortization period	10 years
Major Supplier Concentration Risk [Member] | Minimum [Member] | Cost of Goods, Total [Member]
Significant Accounting Policies [Line Items]
Goodwill impairment test period	3 years
Major Supplier Concentration Risk [Member] | Maximum [Member] | Cost of Goods, Total [Member]
Significant Accounting Policies [Line Items]
Goodwill impairment test period	5 years

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Summary of Property and Equipment Estimated Useful Life (Detail)	12 Months Ended
	Sep. 30, 2019
Building and Building Improvements [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life	40 years
Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life	7 years
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life	Shorter of the estimated useful life or the term of the lease, considering renewal options expected to be exercised.
Minimum [Member] | Equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life	3 years
Maximum [Member] | Equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life	7 years

Acquisitions - Additional Infor

Acquisitions - Additional Information (Detail)

Jul. 16, 2018USD ($)Location

May 01, 2018USD ($)Location

Jan. 02, 2018USD ($)StateLocation$ / sharesshares

May 01, 2017USD ($)Location

Mar. 01, 2017USD ($)Location

Jan. 09, 2017USD ($)Location

Jan. 03, 2017USD ($)Location

Dec. 16, 2016USD ($)Location

Sep. 30, 2019USD ($)$ / sharesshares

Sep. 30, 2017USD ($)BranchBusiness

Mar. 31, 2019USD ($)

Sep. 30, 2018USD ($)Branch$ / sharesshares

Mar. 31, 2018USD ($)

Oct. 25, 2017USD ($)

Business Acquisition [Line Items]

Preferred stock, issuance | shares

0

0

Mezzanine equity

$ 399,195,000

$ 399,195,000

Common stock, par value | $ / shares

$ 0.01

$ 0.01

Number of business locations acquired | Branch

23

7

Business acquisitions purchase price allocation goodwill amount

$ 2,490,590,000

$ 1,251,986,000

$ 2,491,779,000

Number of business locations acquired | Business

5

Senior Notes, Matures November 2025 [Member]

Business Acquisition [Line Items]

Debt instrument, aggregate principal amount

$ 1,300,000,000

Allied Acquisition [Member]

Business Acquisition [Line Items]

Adjusted purchase price

2,880,000,000

$ 2,877,071,000

$ 2,745,882,000

Net working capital adjustment

88,100,000

Business acquisition purchase price and tax position

164,000,000

Number of business locations acquired | Location

208

Number of states business location acquired | State

31

Business acquisition, goodwill, tax deductible amount

1,100,000,000

Business acquisitions purchase price allocation goodwill amount

1,232,780,000

1,130,635,000

Business acquisitions purchase price allocation intangible assets other than goodwill

$ 1,037,000,000

$ 1,037,000,000

Allied Acquisition [Member] | Investment Agreement [Member] | Series A Cumulative Convertible Participating Preferred Stock [Member]

Business Acquisition [Line Items]

Preferred stock, issuance | shares

400,000

Preferred stock, par value | $ / shares

$ 0.01

Preferred stock, liquidation preference value

$ 400,000,000

Preferred stock, liquidation purchase price per share | $ / shares

$ 1,000

Proceeds from convertible preferred stock

$ 400,000,000

Preferred stock conversion price per share | $ / shares

$ 41.26

Preferred stock dividend rate

6.00%

Mezzanine equity

399,200,000

Unamortized issuance costs

800,000

Allied Acquisition [Member] | Secured Term Loan B Facility [Member]

Business Acquisition [Line Items]

Long-term line of credit

$ 970,000,000

Allied Acquisition [Member] | Secured Term Loan B Facility [Member] | LIBOR [Member]

Business Acquisition [Line Items]

Base borrowing rates

1.25%

Allied Acquisition [Member] | Senior Notes, Matures November 2025 [Member]

Business Acquisition [Line Items]

Debt instrument, aggregate principal amount

$ 1,300,000,000

Allied Acquisition [Member] | Senior-secured Asset-based Revolving Line Of Credit [Member] | LIBOR [Member]

Business Acquisition [Line Items]

Base borrowing rates

2.25%

Allied Acquisition [Member] | Stock Purchase Agreement [Member]

Business Acquisition [Line Items]

Acquisition purchase price in cash

$ 2,625,000,000

Tri-State Builder Supply [Member]

Business Acquisition [Line Items]

Number of business locations acquired | Location

1

Business acquisition, sales reported by acquired entity for last annual period

$ 6,000,000

Atlas Supply, Inc. [Member]

Business Acquisition [Line Items]

Number of business locations acquired | Location

6

Business acquisition, sales reported by acquired entity for last annual period

$ 37,000,000

Series of Individually Immaterial Business Acquisitions [Member]

Business Acquisition [Line Items]

Business acquisition, goodwill, tax deductible amount

$ 7,000,000

Business acquisitions purchase price allocation goodwill amount

$ 53,000,000

7,600,000

Business acquisitions purchase price allocation intangible assets other than goodwill

$ 47,400,000

$ 11,400,000

BJ Supply Company [Member]

Business Acquisition [Line Items]

Number of business locations acquired | Location

1

Business acquisition, sales reported by acquired entity for last annual period

$ 4,000,000

American Building and Roofing, Inc. [Member]

Business Acquisition [Line Items]

Number of business locations acquired | Location

7

Business acquisition, sales reported by acquired entity for last annual period

$ 36,000,000

Eco Insulation Supply [Member]

Business Acquisition [Line Items]

Number of business locations acquired | Location

1

Business acquisition, sales reported by acquired entity for last annual period

$ 8,000,000

Acme Building Materials, Inc. [Member]

Business Acquisition [Line Items]

Number of business locations acquired | Location

3

Business acquisition, sales reported by acquired entity for last annual period

$ 13,000,000

Lowry's Inc. [Member]

Business Acquisition [Line Items]

Number of business locations acquired | Location

11

Business acquisition, sales reported by acquired entity for last annual period

$ 76,000,000

Acquisitions - Schedule of Reco

Acquisitions - Schedule of Recognized Identified Assets Acquired and Liabilities Assumed (Detail) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Mar. 31, 2019	Sep. 30, 2019		Sep. 30, 2018	Mar. 31, 2018	Sep. 30, 2017
Business Combination Separately Recognized Transactions [Line Items]
Goodwill		$ 2,490,590		$ 2,491,779		$ 1,251,986
Goodwill		(513)	[1]	$ 1,240,913
Allied Acquisition [Member]
Business Combination Separately Recognized Transactions [Line Items]
Cash	$ 169				$ 19,322
Accounts receivable	337,549				315,485
Inventory	314,785				322,705
Prepaid and other current assets	75,440				59,279
Property, plant, and equipment	139,360				139,528
Goodwill	1,232,780				1,130,635
Intangible assets	1,037,000				1,037,000
Current liabilities	(259,289)				(271,252)
Non-current liabilities	(723)				(6,820)
Total purchase price	2,877,071	$ 2,880,000			$ 2,745,882
Cash	(19,153)
Accounts receivable	22,064
Inventory	(7,920)
Prepaid and other current assets	16,161
Property, plant, and equipment	(168)
Goodwill	102,145
Current liabilities	11,963
Non-current liabilities	6,097
Total purchase price	$ 131,189
[1]	Reflects purchase accounting adjustments related to fiscal year 2018 acquisition of Atlas Supply, Inc. (see Note 3 for further discussion).

Net Sales - Summary of Net Sale

Net Sales - Summary of Net Sales by Product Line and Geography (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Disaggregation Of Revenue [Line Items]
Net sales	$ 7,105,160	$ 6,418,311	$ 4,376,670
U.S. [Member]
Disaggregation Of Revenue [Line Items]
Net sales	6,918,519
Canada [Member]
Disaggregation Of Revenue [Line Items]
Net sales	186,641
Residential Roofing Products [Member]
Disaggregation Of Revenue [Line Items]
Net sales	3,079,628
Residential Roofing Products [Member] | U.S. [Member]
Disaggregation Of Revenue [Line Items]
Net sales	3,023,266
Residential Roofing Products [Member] | Canada [Member]
Disaggregation Of Revenue [Line Items]
Net sales	56,362
Non-Residential Roofing Products [Member]
Disaggregation Of Revenue [Line Items]
Net sales	1,705,178
Non-Residential Roofing Products [Member] | U.S. [Member]
Disaggregation Of Revenue [Line Items]
Net sales	1,582,757
Non-Residential Roofing Products [Member] | Canada [Member]
Disaggregation Of Revenue [Line Items]
Net sales	122,421
Complementary Building Products [Member]
Disaggregation Of Revenue [Line Items]
Net sales	2,320,354
Complementary Building Products [Member] | U.S. [Member]
Disaggregation Of Revenue [Line Items]
Net sales	2,312,496
Complementary Building Products [Member] | Canada [Member]
Disaggregation Of Revenue [Line Items]
Net sales	$ 7,858

Net Income (Loss) Per Share - C

Net Income (Loss) Per Share - Components and Calculation of Basic and Diluted Net Income (Loss) Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
		Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Earnings Per Share [Abstract]
Net income (loss)		$ (10,612)	$ 98,626	$ 100,864
Dividends on preferred shares	[1]	24,000	18,000	0
Net income (loss) attributable to common shareholders		(34,612)	80,626	100,864
Undistributed income allocated to participating securities			(7,742)
Net income (loss) attributable to common shareholders - basic and diluted		$ (34,612)	$ 72,884	$ 100,864
Weighted-average common shares outstanding - basic		68,424,288	68,012,879	60,315,648
Effect of common share equivalents			1,178,160	1,028,615
Weighted-average common shares outstanding - diluted		68,424,288	69,191,039	61,344,263
Net income (loss) per share - basic	[2]	$ (0.51)	$ 1.07	$ 1.67
Net income (loss) per share - diluted	[2]	$ (0.51)	$ 1.05	$ 1.64
[1]	Year ended September 30, 2019 amount is composed of $5.0 million in undeclared cumulative Preferred Stock dividends, as well as an additional $19.0 million of Preferred Stock dividends that had been declared and paid as of period end Year ended September 30, 2018 amount is composed of $5.0 million in undeclared cumulative Preferred Stock dividends, as well as an additional $13.0 million of Preferred Stock dividends that had been declared and paid as of period end
[2]	See Note 5 for detailed calculations and further discussion.

Net Income (Loss) Per Share - S

Net Income (Loss) Per Share - Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share (Detail) - shares	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Preferred Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of diluted net income (loss) per share	9,694,619	7,224,483
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of diluted net income (loss) per share	1,336,259	388,731	331,681
Restricted Stock Units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of diluted net income (loss) per share	122,278	192,151	61,890

Prepaid Expenses and Other Cu_3

Prepaid Expenses and Other Current Assets - Schedule of Prepaid Expenses and Other Current Assets (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Sep. 30, 2018
Prepaid Expenses And Other Current Assets [Abstract]
Vendor rebates	$ 262,876	$ 199,725
Other	52,767	44,635
Total prepaid expenses and other current assets	$ 315,643	$ 244,360

Property and Equipment - Proper

Property and Equipment - Property and Equipment, net (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Sep. 30, 2018
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 571,431	$ 537,277
Accumulated depreciation	(311,055)	(256,870)
Total property and equipment, net	260,376	280,407
Land and Buildings [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	83,373	82,991
Equipment [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	448,072	419,385
Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 39,986	$ 34,901

Property and Equipment - Additi

Property and Equipment - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Property Plant And Equipment [Abstract]
Depreciation	$ 70,695	$ 60,318	$ 34,002

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets - Summary of Changes in goodwill (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2019		Sep. 30, 2018
Goodwill And Intangible Assets Disclosure [Abstract]
Beginning balance	$ 2,491,779		$ 1,251,986
Acquisitions	(513)	[1]	1,240,913
Translation and other adjustments	(676)		(1,120)
Ending balance	$ 2,490,590		$ 2,491,779
[1]	Reflects purchase accounting adjustments related to fiscal year 2018 acquisition of Atlas Supply, Inc. (see Note 3 for further discussion).

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Goodwill And Intangible Assets [Line Items]
Finite-lived Intangible Assets Acquired		$ 1,050,000
Amortization of Intangible Assets	$ 207,065	141,185	$ 82,465
Minimum [Member]
Goodwill And Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	5 years
Maximum [Member]
Goodwill And Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	20 years
Weighted Average [Member]
Goodwill And Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	17 years 6 months
Trademarks [Member]
Goodwill And Intangible Assets [Line Items]
Indefinite-lived Intangible Assets Acquired		120,000
Customer Relationships [Member]
Goodwill And Intangible Assets [Line Items]
Finite-lived Intangible Assets Acquired		920,800
Customer Relationships [Member] | Weighted Average [Member]
Goodwill And Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	17 years 7 months 24 days
Beneficial Lease Arrangements [Member]
Goodwill And Intangible Assets [Line Items]
Finite-lived Intangible Assets Acquired		$ 7,000
Beneficial Lease Arrangements [Member] | Weighted Average [Member]
Goodwill And Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	3 years 7 months 2 days

Goodwill and Intangible Asset_4

Goodwill and Intangible Assets - Summary of Intangible Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Finite Lived Intangible Assets [Line Items]
Amortizable intangible assets	$ 1,552,354	$ 1,551,949
Accumulated amortization	(619,864)	(410,633)
Total amortizable intangible assets, net	932,490	1,141,316
Indefinite lived trademarks	193,050	193,050
Total intangibles, net	$ 1,125,540	1,334,366
Weighted Average [Member]
Finite Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	17 years 6 months
Minimum [Member]
Finite Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	5 years
Maximum [Member]
Finite Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	20 years
Noncompete Agreements [Member]
Finite Lived Intangible Assets [Line Items]
Amortizable intangible assets	$ 2,824	2,824
Noncompete Agreements [Member] | Weighted Average [Member]
Finite Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	2 years 5 months 26 days
Customer Relationships [Member]
Finite Lived Intangible Assets [Line Items]
Amortizable intangible assets	$ 1,530,970	1,530,565
Customer Relationships [Member] | Weighted Average [Member]
Finite Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	17 years 7 months 24 days
Trademarks [Member]
Finite Lived Intangible Assets [Line Items]
Amortizable intangible assets	$ 10,500	10,500
Trademarks [Member] | Weighted Average [Member]
Finite Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	6 years 11 months 1 day
Beneficial Lease Arrangements [Member]
Finite Lived Intangible Assets [Line Items]
Amortizable intangible assets	$ 8,060	$ 8,060
Beneficial Lease Arrangements [Member] | Weighted Average [Member]
Finite Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	3 years 7 months 2 days

Goodwill and Intangible Asset_5

Goodwill and Intangible Assets - Summary of Estimated Future Amortization (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Sep. 30, 2018
Goodwill And Intangible Assets Disclosure [Abstract]
2020	$ 179,549
2021	149,980
2022	121,431
2023	97,522
2024	78,873
Thereafter	305,135
Total amortizable intangible assets, net	$ 932,490	$ 1,141,316

Financing Arrangements - Long-t

Financing Arrangements - Long-term Debt Instruments (Detail) - USD ($)		Sep. 30, 2019		Sep. 30, 2018		Jan. 02, 2018
Debt Instrument [Line Items]
Borrowings under revolving lines of credit/term loans, net		$ 80,961,000		$ 92,442,000
Current portion		0		0
Long-term borrowings under senior notes		1,577,788,000		1,573,699,000
Long-term debt, net		2,494,623,000		2,494,725,000
Equipment financing facilities, various maturities through September 2021	[1]	6,885,000		11,222,000
Capital lease obligations, various maturities through November 2021	[2]	6,713,000		12,378,000
Long-term obligations under equipment financing and other, net		4,609,000		13,639,000
Senior Notes, Matures October 2023 [Member]
Debt Instrument [Line Items]
Senior Notes	[3]	294,886,000		293,607,000
Senior Notes, Matures November 2025 [Member]
Debt Instrument [Line Items]
Senior Notes	[4]	1,282,902,000		1,280,092,000
Equipment Financing Facilities and Other [Member]
Debt Instrument [Line Items]
Current portion		(8,989,000)		(9,961,000)
Long-term obligations under equipment financing and other, net		4,609,000		13,639,000
Revolving Lines of Credit [Member]
Debt Instrument [Line Items]
Borrowings under revolving lines of credit/term loans, net		80,961,000		92,442,000
Revolving Lines of Credit [Member] | 2023 ABL [Member]
Debt Instrument [Line Items]
Borrowings under revolving lines of credit/term loans, net		81,000,000
Revolving Lines of Credit [Member] | 2023 ABL [Member] | U.S. [Member]
Debt Instrument [Line Items]
Total Borrowings under revolving lines of credit/term loans	[5]	80,961,000		89,352,000
Revolving Lines of Credit [Member] | 2023 ABL [Member] | Canada [Member]
Debt Instrument [Line Items]
Total Borrowings under revolving lines of credit/term loans	[6]			3,090,000
Term Loan [Member]
Debt Instrument [Line Items]
Current portion		(9,700,000)		(9,700,000)
Borrowings under revolving lines of credit/term loans, net		916,835,000		921,026,000
Term Loan [Member] | Term Loan, Matures January 2025 [Member]
Debt Instrument [Line Items]
Total Borrowings under revolving lines of credit/term loans		$ 926,535,000	[7]	$ 930,726,000	[7]	$ 970,000,000
[1]	Fixed interest rates ranging from 2.33% to 2.89% for all periods presented.
[2]	Fixed interest rates ranging from 2.72% to 10.39% for all periods presented.
[3]	Interest rate of 6.38% for all periods presented.
[4]	Interest rate of 4.88% for all periods presented.
[5]	Effective rate on borrowings of 5.41% and 3.36% as of September 30, 2019 and 2018, respectively.
[6]	Effective rate on borrowings of 3.95% as of September 30, 2018.
[7]	Interest rate of 4.36% and 4.53% as of September 30, 2019 and 2018, respectively.

Financing Arrangements - Long_2

Financing Arrangements - Long-term Debt Instruments (Parenthetical) (Detail)	Jan. 02, 2018	Sep. 30, 2019	Sep. 30, 2018
Equipment Financing Facilities [Member]
Debt Instrument [Line Items]
Debt instrument maturity date		Sep. 30, 2021	Sep. 30, 2021
Equipment Financing Facilities [Member] | Minimum [Member]
Debt Instrument [Line Items]
Equipment financing facilities, fixed interest rate percentage		2.33%	2.33%
Equipment Financing Facilities [Member] | Maximum [Member]
Debt Instrument [Line Items]
Equipment financing facilities, fixed interest rate percentage		2.89%	2.89%
Capital Lease Obligations [Member]
Debt Instrument [Line Items]
Debt instrument maturity date		Nov. 30, 2021	Nov. 30, 2021
Capital Lease Obligations [Member] | Minimum [Member]
Debt Instrument [Line Items]
Capital lease obligations, fixed interest rate percentage		2.72%	2.72%
Capital Lease Obligations [Member] | Maximum [Member]
Debt Instrument [Line Items]
Capital lease obligations, fixed interest rate percentage		10.39%	10.39%
Senior Notes, Matures October 2023 [Member]
Debt Instrument [Line Items]
Debt interest rate at period end		6.38%	6.38%
Debt instrument maturity date		Oct. 1, 2023	Oct. 1, 2023
Senior Notes, Matures November 2025 [Member]
Debt Instrument [Line Items]
Debt interest rate at period end		4.88%	4.88%
Debt instrument maturity date		Nov. 1, 2025	Nov. 1, 2025
Revolving Lines of Credit [Member] | 2023 ABL [Member]
Debt Instrument [Line Items]
Debt instrument maturity date	Jan. 2, 2023
Revolving Lines of Credit [Member] | 2023 ABL [Member] | U.S. [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Interest Rate at Period End		5.41%	3.36%
Line of Credit Facility, Expiration Date		Jan. 2, 2023	Jan. 2, 2023
Revolving Lines of Credit [Member] | 2023 ABL [Member] | Canada [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Interest Rate at Period End			3.95%
Line of Credit Facility, Expiration Date			Jan. 2, 2023
Term Loan [Member] | Term Loan, Matures January 2025 [Member]
Debt Instrument [Line Items]
Debt interest rate at period end		4.36%	4.53%
Debt instrument maturity date	Jan. 2, 2025	Jan. 2, 2025	Jan. 2, 2025

Financing Arrangements - Financ

Financing Arrangements - Financing - Allied Acquisition - Additional Information (Detail) - USD ($)	Jan. 02, 2018	Sep. 30, 2019		Sep. 30, 2018		Sep. 30, 2017	Oct. 01, 2015
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 3,570,000,000						$ 1,450,000,000
Borrowings under senior notes		$ 0		$ 1,300,000,000		$ 0
Payments of debt issuance costs	65,300,000	817,000		65,788,000		1,669,000
Gains (Losses) on Extinguishment of Debt		0		(1,248,000)		$ 0
Allied Financing Arrangements [Member]
Debt Instrument [Line Items]
Payments of debt issuance costs	2,000,000
Gains (Losses) on Extinguishment of Debt	(1,200,000)
Senior Notes, Matures November 2025 [Member]
Debt Instrument [Line Items]
Borrowings under senior notes	1,300,000,000
Revolving Lines of Credit [Member] | 2023 ABL [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	1,300,000,000
Proceeds from Lines of Credit	525,000,000
Term Loan [Member] | Term Loan, Matures January 2025 [Member]
Debt Instrument [Line Items]
Long-term line of credit	$ 970,000,000	$ 926,535,000	[1]	$ 930,726,000	[1]
[1]	Interest rate of 4.36% and 4.53% as of September 30, 2019 and 2018, respectively.

Financing Arrangements - 2023 A

Financing Arrangements - 2023 ABL - Additional Information (Detail)	Jan. 02, 2018USD ($)	Sep. 30, 2019USD ($)Covenant	Sep. 30, 2018USD ($)	Oct. 01, 2015USD ($)
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 3,570,000,000			$ 1,450,000,000
Borrowings under revolving lines of credit/term loans, net		$ 80,961,000	$ 92,442,000
Unamortized debt issuance costs		59,270,000
2023 ABL [Member]
Debt Instrument [Line Items]
Unamortized debt issuance costs		8,143,000
Revolving Lines of Credit [Member]
Debt Instrument [Line Items]
Borrowings under revolving lines of credit/term loans, net		$ 80,961,000	$ 92,442,000
Revolving Lines of Credit [Member] | 2023 ABL [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 1,300,000,000
Debt instrument maturity date	Jan. 2, 2023
Line of credit facility, unused fees		0.25%
Number of financial covenants | Covenant		1
Fixed charge coverage ratio		100.00%
Borrowings under revolving lines of credit/term loans, net		$ 81,000,000
Unamortized debt issuance costs		8,100,000
Revolving Lines of Credit [Member] | U.S. [Member] | 2023 ABL [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 1,200,000,000
Standby letters of credit outstanding		$ 13,300,000
Revolving Lines of Credit [Member] | Canada [Member] | 2023 ABL [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 100,000,000

Financing Arrangements - 2025 T

Financing Arrangements - 2025 Term Loan - Additional Information (Detail) - USD ($)	Jan. 02, 2018	Sep. 30, 2019		Sep. 30, 2018
Debt Instrument [Line Items]
Unamortized debt issuance costs		$ 59,270,000
Term Loan, Matures January 2025 [Member]
Debt Instrument [Line Items]
Unamortized debt issuance costs		28,915,000
Term Loan [Member] | Term Loan, Matures January 2025 [Member]
Debt Instrument [Line Items]
Long-term line of credit	$ 970,000,000	$ 926,535,000	[1]	$ 930,726,000	[1]
Debt Instrument, Frequency of Periodic Payment		quarterly
Debt Instrument, Periodic Payment	$ 2,400,000
Debt instrument maturity date	Jan. 2, 2025	Jan. 2, 2025		Jan. 2, 2025
Unamortized debt issuance costs		$ 28,900,000
[1]	Interest rate of 4.36% and 4.53% as of September 30, 2019 and 2018, respectively.

Financing Arrangements - 2025 S

Financing Arrangements - 2025 Senior Notes - Additional Information (Detail) - USD ($)		12 Months Ended
		Sep. 30, 2019	Sep. 30, 2018	Oct. 25, 2017
Debt Instrument [Line Items]
Unamortized debt issuance costs		$ 59,270,000
Senior Notes, Matures November 2025 [Member]
Debt Instrument [Line Items]
Debt instrument, aggregate principal amount				$ 1,300,000,000
Debt instrument interest rate		4.88%	4.88%
Debt instrument, issue price percentage				100.00%
Debt instrument maturity date		Nov. 1, 2025	Nov. 1, 2025
Unamortized debt issuance costs		$ 17,100,000
Senior Notes Payable	[1]	$ 1,282,902,000	$ 1,280,092,000
[1]	Interest rate of 4.88% for all periods presented.

Financing Arrangements - Fina_2

Financing Arrangements - Financing - RSG Acquisition - Additional Information (Detail) - USD ($)	Jan. 02, 2018	Oct. 01, 2015	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 3,570,000,000	$ 1,450,000,000
Borrowings under senior notes			$ 0	$ 1,300,000,000	$ 0
Payments of debt issuance costs	$ 65,300,000		817,000	$ 65,788,000	$ 1,669,000
Roofing Supply Group [Member]
Debt Instrument [Line Items]
Payments of debt issuance costs			$ 31,300,000
2020 ABL [Member] | Revolving Lines of Credit [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		700,000,000
Proceeds from Lines of Credit		350,000,000
2022 Term Loan [Member] | Term Loan [Member]
Debt Instrument [Line Items]
Long-term line of credit		450,000,000
Senior Notes, Matures October 2023 [Member]
Debt Instrument [Line Items]
Borrowings under senior notes		$ 300,000,000

Financing Arrangements - 2020 A

Financing Arrangements - 2020 ABL - Additional Information (Detail) - USD ($)	Oct. 01, 2015	Jan. 02, 2018
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 1,450,000,000	$ 3,570,000,000
Revolving Lines of Credit [Member] | 2020 ABL [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 700,000,000
Debt instrument maturity date	Oct. 1, 2020
Debt instrument paid off date	Jan. 2, 2018
U.S. [Member] | Revolving Lines of Credit [Member] | 2020 ABL [Member]
Debt Instrument [Line Items]
Long-term line of credit	$ 670,000,000
Canada [Member] | Revolving Lines of Credit [Member] | 2020 ABL [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 30,000,000

Financing Arrangements - 2022 T

Financing Arrangements - 2022 Term Loan - Additional Information (Detail) - Term Loan [Member] - 2022 Term Loan [Member] $ in Millions	Oct. 01, 2015USD ($)
Debt Instrument [Line Items]
Long-term line of credit	$ 450
Debt instrument paid off date	Jan. 2, 2018
Write off of debt issuance costs	$ 0.7
Debt Instrument, Frequency of Periodic Payment	quarterly
Debt Instrument, Periodic Payment	$ 1.1
Debt instrument maturity date	Oct. 1, 2022

Financing Arrangements - 2023 S

Financing Arrangements - 2023 Senior Notes - Additional Information (Detail) - USD ($) $ in Thousands		Oct. 01, 2015	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Debt Instrument [Line Items]
Borrowings under senior notes			$ 0	$ 1,300,000	$ 0
Unamortized debt issuance costs			59,270
Senior Notes, Matures October 2023 [Member]
Debt Instrument [Line Items]
Borrowings under senior notes		$ 300,000
Debt instrument, coupon rate		6.38%
Unamortized debt issuance costs			5,100
Senior Notes Payable	[1]		$ 294,886	$ 293,607
[1]	Interest rate of 6.38% for all periods presented.

Financing Arrangements - Schedu

Financing Arrangements - Schedule of Maturities of Long-term Debt (Detail) $ in Thousands	Sep. 30, 2019USD ($)
Debt Instrument [Line Items]
2020	$ 18,689
2021	14,067
2022	9,913
2023	398,833
2024	9,700
Thereafter	2,206,950
Total debt	2,658,152
Unamortized debt issuance costs	(59,270)
Total long-term debt	2,598,882
2023 ABL [Member]
Debt Instrument [Line Items]
2020	0
2021	0
2022	0
2023	89,104
2024	0
Thereafter	0
Total debt	89,104
Unamortized debt issuance costs	(8,143)
Total long-term debt	80,961
2025 Term Loan [Member]
Debt Instrument [Line Items]
2020	9,700
2021	9,700
2022	9,700
2023	9,700
2024	9,700
Thereafter	906,950
Total debt	955,450
Unamortized debt issuance costs	(28,915)
Total long-term debt	926,535
Equipment Financing and Other [Member]
Debt Instrument [Line Items]
2020	8,989
2021	4,367
2022	213
2023	29
2024	0
Thereafter	0
Total debt	13,598
Unamortized debt issuance costs	0
Total long-term debt	13,598
Senior Notes [Member]
Debt Instrument [Line Items]
2020	0	[1]
2021	0	[1]
2022	0	[1]
2023	300,000	[1]
2024	0	[1]
Thereafter	1,300,000	[1]
Total debt	1,600,000	[1]
Unamortized debt issuance costs	(22,212)	[1]
Total long-term debt	$ 1,577,788	[1]
[1]	Represent principal amounts for 2023 Senior Notes and 2025 Senior Notes. In October 2019, the 2023 Senior Notes were fully redeemed and replaced in connection with re-financing efforts (see Note 20 for additional information).

Commitments and Contingencies -

Commitments and Contingencies - Schedule of Minimum Rental Commitments under Non-cancelable Operating Leases (Detail) $ in Thousands	Sep. 30, 2019USD ($)
Commitments And Contingencies Disclosure [Abstract]
2020	$ 110,858
2021	103,185
2022	88,086
2023	70,839
2024	54,185
Thereafter	100,256
Total minimum lease payments	$ 527,409

Commitments and Contingencies_2

Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Commitments And Contingencies Disclosure [Abstract]
Rent expense	$ 110.6	$ 99.1	$ 60.1

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Income (Loss) - Reclassification out of Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	$ 1,884,305	$ 1,781,806	$ 1,323,827
Other comprehensive income (loss) before reclassifications	(3,346)	(2,687)	3,706
Reclassifications out of other comprehensive loss			388
Balance	1,862,353	1,884,305	1,781,806
Foreign Currency Translation
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	(17,250)	(14,563)	(18,269)
Other comprehensive income (loss) before reclassifications	(1,734)	(2,687)	3,706
Balance	(18,984)	(17,250)	(14,563)
Derivative Financial Instruments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance			(388)
Other comprehensive income (loss) before reclassifications	(1,612)
Reclassifications out of other comprehensive loss			388
Balance	(1,612)
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	(17,250)	(14,563)	(18,657)
Balance	$ (20,596)	$ (17,250)	$ (14,563)

Stock-based Compensation - Addi

Stock-based Compensation - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017	Feb. 09, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock (voting), shares authorized	100,000,000	100,000,000
Common Stock (voting), issued	68,574,176	68,135,790
Common Stock (voting), outstanding	68,574,176	68,135,790
Stock-based compensation number of shares authorized				5,000,000
Stock-based compensation number of shares available for awards	1,781,109
Restricted Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of shares that will vest	100.00%
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-qualified options granted expiration period	10 years
Vesting period	3 years
Allocated stock-based compensation expense	$ 4.1	$ 3.9	$ 4.8
Unrecognized compensation cost related to unvested stock	$ 5.4
Unrecognized compensation cost related to unvested stock, expected weighted-average period of recognition	1 year 10 months 24 days
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated stock-based compensation expense	$ 12.3	12.6	$ 10.3
Unrecognized compensation cost related to unvested stock		$ 14.3
Unrecognized compensation cost related to unvested stock, expected weighted-average period of recognition	1 year 7 months 6 days
Restricted Stock Units (RSUs) [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of shares that will vest	0.00%
Restricted Stock Units (RSUs) [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of shares that will vest	200.00%

Stock-based Compensation - Fair

Stock-based Compensation - Fair Values of Options, Black-Scholes Option-Pricing Model, Weighted-Average Assumptions (Detail)	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Risk-free interest rate	2.86%	2.10%	1.97%
Expected volatility	29.68%	26.43%	28.83%
Expected life (in years)	5 years 2 months 19 days	5 years 5 months 15 days	5 years 3 months 18 days
Dividend yield	0.00%	0.00%	0.00%

Stock-based compensation - Stoc

Stock-based compensation - Stock Options Outstanding and Activity During the Period (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Options Outstanding
Balance as of September 30, 2018	1,969,037
Granted	674,015
Exercised	(183,347)
Canceled/Forfeited	(117,108)
Expired	(3,108)
Balance as of September 30, 2019	2,339,489	1,969,037
Vested and expected to vest after September 30, 2019	2,305,869
Exercisable as of September 30, 2019	1,484,158
Weighted-Average Exercise Price
Beginning Balance	$ 33.08
Granted	27.67
Exercised	18.08
Canceled/Forfeited	35.18
Expired	26.74
Ending Balance	32.61	$ 33.08
Vested and expected to vest after September 30, 2019	32.62
Exercisable as of September 30, 2019	$ 31.54
Weighted-Average Remaining Contractual Life
Balance	6 years 1 month 6 days	5 years 8 months 12 days
Vested and expected to vest after September 30, 2019	6 years 1 month 6 days
Exercisable as of September 30, 2019	4 years 6 months
Aggregate Intrinsic Value
Balance	$ 12,034	$ 14,088
Vested and expected to vest after September 30, 2019	11,870
Exercisable as of September 30, 2019	$ 8,343

Stock-based compensation - St_2

Stock-based compensation - Stock Option Grants, Vesting, and Exercises (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Weighted-average fair value of stock options granted	$ 8.91	$ 15.86	$ 14.21
Total grant date fair value of stock options vested	$ 3,850	$ 4,208	$ 5,541
Total intrinsic value of stock options exercised	$ 2,849	$ 9,645	$ 10,941

Stock-based Compensation - Rest

Stock-based Compensation - Restricted Shares and Units Outstanding and Activity During the Period (Detail) - $ / shares	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Weighted - Average Grant Date Fair Value
Granted	$ 28.02	$ 57.40	$ 47.31
Restricted Stock Units (RSUs) [Member]
Outstanding
Balance as of September 30, 2018	934,023
Granted	722,531
Released	(375,084)
Canceled/Forfeited	(158,112)
Balance as of September 30, 2019	1,123,358	934,023
Vested and expected to vest after September 30, 2019	908,892
Weighted - Average Grant Date Fair Value
Balance as of September 30, 2018	$ 47
Granted	28.02
Released	40.65
Canceled/Forfeited	42.92
Balance as of September 30, 2019	37.48	$ 47
Vested and expected to vest after September 30, 2019	$ 39.41

Stock-based Compensation - Sche

Stock-based Compensation - Schedule Of Restricted Stock Units Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Weighted-average fair value of RSUs granted	$ 28.02	$ 57.40	$ 47.31
Total grant date fair value of RSUs vested	$ 16,087	$ 6,656	$ 4,562
Total intrinsic value of RSUs released	$ 11,460	$ 11,041	$ 6,079

Income Taxes - Summary of Compo

Income Taxes - Summary of Components of Income Tax Provision (Benefit) (Detail) - USD ($) $ in Thousands		12 Months Ended
		Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Current:
Federal		$ 0	$ (4,435)	$ 52,718
Foreign		579	492	1,366
State		1,647	3,516	8,975
Total current taxes		2,226	(427)	63,059
Deferred:
Federal		(1,452)	(35,249)	(656)
Foreign		0	(173)	0
State		(944)	5,305	78
Total deferred taxes		(2,396)	(30,117)	(578)
Provision for (benefit from) income taxes	[1]	$ (170)	$ (30,544)	$ 62,481
[1]	Year ended September 30, 2018 amounts include a net tax benefit $49.2 million resulting from recording the provisional impact of the enactment of the 2017 Tax Cuts and Jobs Act (“TCJA”).

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Statutory Federal Income Tax Rate (Detail)	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Income Tax Disclosure [Abstract]
U.S. federal income taxes at statutory rate	21.00%	24.50%	35.00%
State income taxes, net of federal benefit	(3.30%)	5.20%	3.90%
Share-based payments	(4.70%)	(3.90%)	0.00%
Deferred tax asset/liability remeasurement	0.00%	(73.50%)	0.00%
Repatriation transition tax	4.30%	1.80%	0.00%
Non-deductible meals and entertainment	(13.90%)	2.20%	0.60%
Other	(1.80%)	(1.20%)	(1.20%)
Effective tax rate	1.60%	(44.90%)	38.30%

Income Taxes - Schedule of Temp

Income Taxes - Schedule of Temporary Differences That Give Rise to Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Sep. 30, 2018
Deferred tax assets:
Deferred compensation	$ 11,099	$ 11,346
Allowance for doubtful accounts	4,218	663
Accrued vacation and other	5,148	5,079
Inventory valuation	14,307	12,900
Tax loss carryforwards	18,272	17,271
Unrealized loss on financial derivatives	510
Other	1,611	1,517
Total deferred tax assets	55,165	48,776
Deferred tax liabilities:
Excess tax over book depreciation and amortization	(159,078)	(155,770)
Total deferred tax liabilities	(159,078)	(155,770)
Net deferred income tax liabilities	$ (103,913)	$ (106,994)

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail)	12 Months Ended
	Sep. 30, 2019USD ($)StateProvince	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)	Sep. 30, 2016USD ($)
Operating loss carryforwards	$ 31,500,000			$ 135,300,000
Net operating loss carryforward utilized	26,300,000
Goodwill	2,490,590,000	$ 2,491,779,000	$ 1,251,986,000
Goodwill amortizable for income tax	1,100,000,000
Uncertain tax positions	$ 0
U.S. [Member]
Number of States in which Entity Operates | State	50
Canada [Member]
Number of provinces in which entity operates | Province	6

Geographic and Product Data - S

Geographic and Product Data - Schedule Of Geographic Information (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Sep. 30, 2018
Segment Reporting Information [Line Items]
Long-lived assets	$ 1,194,925	$ 1,422,966
U.S. [Member]
Segment Reporting Information [Line Items]
Long-lived assets	1,182,552	1,409,742
Canada [Member]
Segment Reporting Information [Line Items]
Long-lived assets	$ 12,373	$ 13,224

Supplemental Guarantor Inform_3

Supplemental Guarantor Information - Condensed Consolidating Balance Sheets (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Current assets:
Cash and cash equivalents	$ 72,287	$ 129,927
Accounts receivable, net	1,108,134	1,090,533
Inventories, net	1,018,183	936,047
Prepaid expenses and other current assets	315,643	244,360
Total current assets	2,514,247	2,400,867
Intercompany receivable, net	0	0
Investments in consolidated subsidiaries	0	0
Deferred income taxes, net	0	0
Property and equipment, net	260,376	280,407
Goodwill	2,490,590	2,491,779	$ 1,251,986
Intangibles, net	1,125,540	1,334,366
Other assets, net	2,059	1,243
Total assets	6,392,812	6,508,662
Current liabilities:
Accounts payable	822,931	880,872
Accrued expenses	599,155	611,539
Current portions of long-term debt/obligations	18,689	19,661
Total current liabilities	1,440,775	1,512,072
Intercompany payable, net	0	0
Borrowings under revolving lines of credit, net	80,961	92,442
Long-term debt, net	2,494,623	2,494,725
Deferred income taxes, net	103,913	106,994
Long-term obligations under equipment financing and other, net	4,609	13,639
Other long-term liabilities	6,383	5,290
Total liabilities	4,131,264	4,225,162
Convertible preferred stock	399,195	399,195
Total stockholders' equity	1,862,353	1,884,305	$ 1,781,806	$ 1,323,827
Total liabilities and stockholders' equity	6,392,812	6,508,662
Reportable Legal Entities [Member] | Parent Company [Member]
Current assets:
Cash and cash equivalents	0	0
Accounts receivable, net	0	0
Inventories, net	0	0
Prepaid expenses and other current assets	15,788	23,711
Total current assets	15,788	23,711
Intercompany receivable, net	0	0
Investments in consolidated subsidiaries	6,365,732	6,109,325
Deferred income taxes, net	17,123	22,475
Property and equipment, net	20,507	18,929
Goodwill	0	0
Intangibles, net	0	0
Other assets, net	2,059	1,243
Total assets	6,421,209	6,175,683
Current liabilities:
Accounts payable	51,142	24,154
Accrued expenses	80,556	41,448
Current portions of long-term debt/obligations	9,700	9,700
Total current liabilities	141,398	75,302
Intercompany payable, net	1,523,640	1,322,156
Borrowings under revolving lines of credit, net	0	0
Long-term debt, net	2,494,623	2,494,725
Deferred income taxes, net	0	0
Long-term obligations under equipment financing and other, net	0	0
Other long-term liabilities	0	0
Total liabilities	4,159,661	3,892,183
Convertible preferred stock	399,195	399,195
Total stockholders' equity	1,862,353	1,884,305
Total liabilities and stockholders' equity	6,421,209	6,175,683
Reportable Legal Entities [Member] | Guarantor Subsidiaries [Member]
Current assets:
Cash and cash equivalents	65,213	136,499
Accounts receivable, net	1,067,109	1,051,410
Inventories, net	988,925	907,605
Prepaid expenses and other current assets	291,736	214,011
Total current assets	2,412,983	2,309,525
Intercompany receivable, net	1,561,217	1,361,615
Investments in consolidated subsidiaries	0	0
Deferred income taxes, net	0	0
Property and equipment, net	229,267	250,517
Goodwill	2,461,212	2,461,725
Intangibles, net	1,123,768	1,332,104
Other assets, net	0	0
Total assets	7,788,447	7,715,486
Current liabilities:
Accounts payable	745,820	843,907
Accrued expenses	504,150	564,331
Current portions of long-term debt/obligations	8,989	9,961
Total current liabilities	1,258,959	1,418,199
Intercompany payable, net	0	0
Borrowings under revolving lines of credit, net	80,961	89,352
Long-term debt, net	0	0
Deferred income taxes, net	120,643	128,846
Long-term obligations under equipment financing and other, net	4,609	13,639
Other long-term liabilities	6,301	5,207
Total liabilities	1,471,473	1,655,243
Convertible preferred stock	0	0
Total stockholders' equity	6,316,974	6,060,243
Total liabilities and stockholders' equity	7,788,447	7,715,486
Reportable Legal Entities [Member] | Non-Guarantor Subsidiaries [Member]
Current assets:
Cash and cash equivalents	7,074	1,959
Accounts receivable, net	42,165	40,262
Inventories, net	29,258	28,442
Prepaid expenses and other current assets	8,119	6,638
Total current assets	86,616	77,301
Intercompany receivable, net	0	0
Investments in consolidated subsidiaries	0	0
Deferred income taxes, net	0	0
Property and equipment, net	10,602	10,961
Goodwill	29,378	30,054
Intangibles, net	1,772	2,262
Other assets, net	0	0
Total assets	128,368	120,578
Current liabilities:
Accounts payable	27,109	22,482
Accrued expenses	14,449	5,760
Current portions of long-term debt/obligations	0	0
Total current liabilities	41,558	28,242
Intercompany payable, net	37,577	39,459
Borrowings under revolving lines of credit, net	0	3,090
Long-term debt, net	0	0
Deferred income taxes, net	393	622
Long-term obligations under equipment financing and other, net	0	0
Other long-term liabilities	82	83
Total liabilities	79,610	71,496
Convertible preferred stock	0	0
Total stockholders' equity	48,758	49,082
Total liabilities and stockholders' equity	128,368	120,578
Eliminations and Other [Member]
Current assets:
Cash and cash equivalents	0	(8,531)
Accounts receivable, net	(1,140)	(1,139)
Inventories, net	0	0
Prepaid expenses and other current assets	0	0
Total current assets	(1,140)	(9,670)
Intercompany receivable, net	(1,561,217)	(1,361,615)
Investments in consolidated subsidiaries	(6,365,732)	(6,109,325)
Deferred income taxes, net	(17,123)	(22,475)
Property and equipment, net	0	0
Goodwill	0	0
Intangibles, net	0	0
Other assets, net	0	0
Total assets	(7,945,212)	(7,503,085)
Current liabilities:
Accounts payable	(1,140)	(9,671)
Accrued expenses	0	0
Current portions of long-term debt/obligations	0	0
Total current liabilities	(1,140)	(9,671)
Intercompany payable, net	(1,561,217)	(1,361,615)
Borrowings under revolving lines of credit, net	0	0
Long-term debt, net	0	0
Deferred income taxes, net	(17,123)	(22,474)
Long-term obligations under equipment financing and other, net	0	0
Other long-term liabilities	0	0
Total liabilities	(1,579,480)	(1,393,760)
Convertible preferred stock	0	0
Total stockholders' equity	(6,365,732)	(6,109,325)
Total liabilities and stockholders' equity	$ (7,945,212)	$ (7,503,085)

Supplemental Guarantor Inform_4

Supplemental Guarantor Information - Condensed Consolidating Statements of Operations (Detail) - USD ($) $ in Thousands		12 Months Ended
		Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Net sales		$ 7,105,160	$ 6,418,311	$ 4,376,670
Cost of products sold		5,368,605	4,824,990	3,300,731
Gross profit		1,736,555	1,593,321	1,075,939
Operating expense
Selling, general and administrative		1,311,043	1,187,192	743,376
Depreciation		70,695	60,318	34,002
Amortization		207,065	141,185	82,465
Total operating expense		1,588,803	1,388,695	859,843
Intercompany charges (income)		0	0	0
Income (loss) from operations		147,752	204,626	216,096
Interest expense, financing costs, and other		158,534	136,544	52,751
Intercompany interest expense (income)		0	0	0
Income (loss) before provision for income taxes		(10,782)	68,082	163,345
Provision for (benefit from) income taxes	[1]	(170)	(30,544)	62,481
Income (loss) before equity in net income of subsidiaries		(10,612)	98,626	100,864
Equity in net income of subsidiaries		0	0	0
Net income (loss)		(10,612)	98,626	100,864
Reportable Legal Entities [Member] | Parent Company [Member]
Net sales		0	0	0
Cost of products sold		0	0	0
Gross profit		0	0	0
Operating expense
Selling, general and administrative		17,627	5,909	26,962
Depreciation		4,027	1,989	1,534
Amortization		0	0	0
Total operating expense		21,654	7,898	28,496
Intercompany charges (income)		(17,576)	(6,734)	(4,664)
Income (loss) from operations		(4,078)	(1,164)	(23,832)
Interest expense, financing costs, and other		140,489	124,169	38,660
Intercompany interest expense (income)		(39,670)	(24,270)	(24,458)
Income (loss) before provision for income taxes		(104,897)	(101,063)	(38,034)
Provision for (benefit from) income taxes		(116)	11,398	(3,284)
Income (loss) before equity in net income of subsidiaries		(104,781)	(112,461)	(34,750)
Equity in net income of subsidiaries		94,169	211,087	135,614
Net income (loss)		(10,612)	98,626	100,864
Reportable Legal Entities [Member] | Guarantor Subsidiaries [Member]
Net sales		6,918,518	6,239,332	4,198,935
Cost of products sold		5,220,994	4,685,616	3,162,896
Gross profit		1,697,524	1,553,716	1,036,039
Operating expense
Selling, general and administrative		1,261,370	1,147,390	685,690
Depreciation		64,801	56,598	30,758
Amortization		206,627	140,664	81,880
Total operating expense		1,532,798	1,344,652	798,328
Intercompany charges (income)		17,132	6,565	4,342
Income (loss) from operations		147,594	202,499	233,369
Interest expense, financing costs, and other		17,327	11,648	14,033
Intercompany interest expense (income)		38,142	22,738	22,927
Income (loss) before provision for income taxes		92,125	168,113	196,409
Provision for (benefit from) income taxes		(632)	(42,261)	64,399
Income (loss) before equity in net income of subsidiaries		92,757	210,374	132,010
Equity in net income of subsidiaries		0	0	0
Net income (loss)		92,757	210,374	132,010
Reportable Legal Entities [Member] | Non-Guarantor Subsidiaries [Member]
Net sales		186,642	178,979	177,735
Cost of products sold		147,611	139,374	137,835
Gross profit		39,031	39,605	39,900
Operating expense
Selling, general and administrative		32,046	33,893	30,724
Depreciation		1,867	1,731	1,710
Amortization		438	521	585
Total operating expense		34,351	36,145	33,019
Intercompany charges (income)		444	169	322
Income (loss) from operations		4,236	3,291	6,559
Interest expense, financing costs, and other		718	727	58
Intercompany interest expense (income)		1,528	1,532	1,531
Income (loss) before provision for income taxes		1,990	1,032	4,970
Provision for (benefit from) income taxes		578	319	1,366
Income (loss) before equity in net income of subsidiaries		1,412	713	3,604
Equity in net income of subsidiaries		0	0	0
Net income (loss)		1,412	713	3,604
Eliminations and Other [Member]
Net sales		0	0	0
Cost of products sold		0	0	0
Gross profit		0	0	0
Operating expense
Selling, general and administrative		0	0	0
Depreciation		0	0	0
Amortization		0	0	0
Total operating expense		0	0	0
Intercompany charges (income)		0	0	0
Income (loss) from operations		0	0	0
Interest expense, financing costs, and other		0	0	0
Intercompany interest expense (income)		0	0	0
Income (loss) before provision for income taxes		0	0	0
Provision for (benefit from) income taxes		0	0	0
Income (loss) before equity in net income of subsidiaries		0	0	0
Equity in net income of subsidiaries		(94,169)	(211,087)	(135,614)
Net income (loss)		$ (94,169)	$ (211,087)	$ (135,614)
[1]	Year ended September 30, 2018 amounts include a net tax benefit $49.2 million resulting from recording the provisional impact of the enactment of the 2017 Tax Cuts and Jobs Act (“TCJA”).

Supplemental Guarantor Inform_5

Supplemental Guarantor Information - Condensed Consolidating Statements of Comprehensive Income (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Net income (loss)	$ (10,612)	$ 98,626	$ 100,864
Other comprehensive income (loss):
Foreign currency translation adjustment	(1,734)	(2,687)	3,706
Unrealized gain (loss) due to change in fair value of derivatives, net of tax	(1,612)	0	0
Total other comprehensive income (loss)	(3,346)	(2,687)	3,706
Comprehensive income (loss)	(13,958)	95,939	104,570
Reportable Legal Entities [Member] | Parent Company [Member]
Net income (loss)	(10,612)	98,626	100,864
Other comprehensive income (loss):
Foreign currency translation adjustment	(1,734)	(2,687)	3,706
Unrealized gain (loss) due to change in fair value of derivatives, net of tax	(1,612)
Total other comprehensive income (loss)	(3,346)	(2,687)	3,706
Comprehensive income (loss)	(13,958)	95,939	104,570
Reportable Legal Entities [Member] | Guarantor Subsidiaries [Member]
Net income (loss)	92,757	210,374	132,010
Other comprehensive income (loss):
Foreign currency translation adjustment	0	0	0
Unrealized gain (loss) due to change in fair value of derivatives, net of tax	0
Total other comprehensive income (loss)	0	0	0
Comprehensive income (loss)	92,757	210,374	132,010
Reportable Legal Entities [Member] | Non-Guarantor Subsidiaries [Member]
Net income (loss)	1,412	713	3,604
Other comprehensive income (loss):
Foreign currency translation adjustment	(1,734)	(2,687)	3,706
Unrealized gain (loss) due to change in fair value of derivatives, net of tax	(1,612)
Total other comprehensive income (loss)	(3,346)	(2,687)	3,706
Comprehensive income (loss)	(1,934)	(1,974)	7,310
Eliminations and Other [Member]
Net income (loss)	(94,169)	(211,087)	(135,614)
Other comprehensive income (loss):
Foreign currency translation adjustment	1,734	2,687	(3,706)
Unrealized gain (loss) due to change in fair value of derivatives, net of tax	1,612
Total other comprehensive income (loss)	3,346	2,687	(3,706)
Comprehensive income (loss)	$ (90,823)	$ (208,400)	$ (139,320)

Supplemental Guarantor Inform_6

Supplemental Guarantor Information - Condensed Consolidating Statements of Cash Flows (Detail) - USD ($) $ in Thousands	Jan. 02, 2018	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Net cash provided by (used in) operating activities		$ 212,653	$ 539,381	$ 315,200
Investing Activities
Purchases of property and equipment		(57,031)	(46,010)	(39,828)
Acquisition of businesses, net		(163,973)	(2,740,480)	(129,390)
Proceeds from the sale of assets		9,269	2,149	2,233
Intercompany activity		0	0	0
Net cash provided by (used in) investing activities		(211,735)	(2,784,341)	(166,985)
Financing Activities
Borrowings under revolving lines of credit		2,100,085	2,807,741	2,464,128
Repayments under revolving lines of credit		(2,113,982)	(2,707,741)	(2,833,230)
Borrowings under term loan		0	970,000	0
Repayments under term loan		(9,700)	(445,850)	(4,500)
Borrowings under senior notes		0	1,300,000	0
Payment of debt issuance costs	$ (65,300)	(817)	(65,788)	(1,669)
Repayments under equipment financing facilities and other		(10,001)	(11,593)	(10,034)
Proceeds from secondary offering of common stock		0	0	345,503
Proceeds from issuance of convertible preferred stock		0	400,000	0
Payment of stock issuance costs		0	(1,279)	(14,684)
Payment of dividends on preferred stock		(24,000)	(12,978)	0
Proceeds from issuance of common stock related to equity awards		3,314	7,514	11,341
Taxes paid related to net share settlement of equity awards		(3,668)	(3,975)	(392)
Excess tax benefit from stock-based compensation		0	0	2,937
Intercompany activity		0	0	0
Net cash provided by (used in) financing activities		(58,769)	2,236,051	(40,600)
Effect of exchange rate changes on cash and cash equivalents		211	586	(751)
Net increase (decrease) in cash and cash equivalents		(57,640)	(8,323)	106,864
Cash and cash equivalents, beginning of period		129,927	138,250	31,386
Cash and cash equivalents, end of period		72,287	129,927	138,250
Reportable Legal Entities [Member] | Parent Company [Member]
Net cash provided by (used in) operating activities		6,250	(100,302)	(2,466)
Investing Activities
Purchases of property and equipment		(7,156)	(14,354)	(3,517)
Acquisition of businesses, net		0	(2,740,480)	(129,390)
Proceeds from the sale of assets		0	0	0
Intercompany activity		35,777	699,970	(203,163)
Net cash provided by (used in) investing activities		28,621	(2,054,864)	(336,070)
Financing Activities
Borrowings under term loan			970,000
Repayments under term loan		(9,700)	(445,850)	(4,500)
Borrowings under senior notes			1,300,000
Payment of debt issuance costs		(817)	(58,266)	(1,669)
Repayments under equipment financing facilities and other		0	0	0
Proceeds from secondary offering of common stock				345,503
Proceeds from issuance of convertible preferred stock			400,000
Payment of stock issuance costs			(1,279)	(14,684)
Payment of dividends on preferred stock		(24,000)	(12,978)
Proceeds from issuance of common stock related to equity awards		3,314	7,514	11,341
Taxes paid related to net share settlement of equity awards		(3,668)	(3,975)	(392)
Excess tax benefit from stock-based compensation				2,937
Intercompany activity		0	0	0
Net cash provided by (used in) financing activities		(34,871)	2,155,166	338,536
Effect of exchange rate changes on cash and cash equivalents		0	0	0
Net increase (decrease) in cash and cash equivalents		0	0	0
Cash and cash equivalents, beginning of period		0	0	0
Cash and cash equivalents, end of period		0	0	0
Reportable Legal Entities [Member] | Guarantor Subsidiaries [Member]
Net cash provided by (used in) operating activities		188,268	638,451	313,396
Investing Activities
Purchases of property and equipment		(48,311)	(29,132)	(34,584)
Acquisition of businesses, net		(163,973)	0	0
Proceeds from the sale of assets		9,256	2,121	2,150
Intercompany activity		0	0	0
Net cash provided by (used in) investing activities		(203,028)	(27,011)	(32,434)
Financing Activities
Borrowings under term loan			0
Repayments under term loan		0	0	0
Borrowings under senior notes			0
Payment of debt issuance costs		0	(7,522)	0
Repayments under equipment financing facilities and other		(10,001)	(11,593)	(10,049)
Proceeds from secondary offering of common stock				0
Proceeds from issuance of convertible preferred stock			0
Payment of stock issuance costs			0	0
Payment of dividends on preferred stock		0	0
Proceeds from issuance of common stock related to equity awards		0	0	0
Taxes paid related to net share settlement of equity awards		0	0	0
Excess tax benefit from stock-based compensation				0
Intercompany activity		(35,629)	(705,625)	209,018
Net cash provided by (used in) financing activities		(56,526)	(624,740)	(168,610)
Effect of exchange rate changes on cash and cash equivalents		0	0	0
Net increase (decrease) in cash and cash equivalents		(71,286)	(13,300)	112,352
Cash and cash equivalents, beginning of period		136,499	149,799	37,447
Cash and cash equivalents, end of period		65,213	136,499	149,799
Reportable Legal Entities [Member] | Non-Guarantor Subsidiaries [Member]
Net cash provided by (used in) operating activities		11,339	(680)	4,888
Investing Activities
Purchases of property and equipment		(1,564)	(2,524)	(1,727)
Acquisition of businesses, net		0	0	0
Proceeds from the sale of assets		13	28	83
Intercompany activity		0	0	0
Net cash provided by (used in) investing activities		(1,551)	(2,496)	(1,644)
Financing Activities
Borrowings under term loan			0
Repayments under term loan		0	0	0
Borrowings under senior notes			0
Payment of debt issuance costs		0	0	0
Repayments under equipment financing facilities and other		0	0	15
Proceeds from secondary offering of common stock				0
Proceeds from issuance of convertible preferred stock			0
Payment of stock issuance costs			0	0
Payment of dividends on preferred stock		0	0
Proceeds from issuance of common stock related to equity awards		0	0	0
Taxes paid related to net share settlement of equity awards		0	0	0
Excess tax benefit from stock-based compensation				0
Intercompany activity		(1,826)	2,967	(2,279)
Net cash provided by (used in) financing activities		(4,827)	2,967	(3,787)
Effect of exchange rate changes on cash and cash equivalents		154	586	(751)
Net increase (decrease) in cash and cash equivalents		5,115	377	(1,294)
Cash and cash equivalents, beginning of period		1,959	1,582	2,876
Cash and cash equivalents, end of period		7,074	1,959	1,582
Eliminations and Other [Member]
Net cash provided by (used in) operating activities		6,796	1,912	(618)
Investing Activities
Purchases of property and equipment		0	0	0
Acquisition of businesses, net		0	0	0
Proceeds from the sale of assets		0	0	0
Intercompany activity		(35,777)	(699,970)	203,163
Net cash provided by (used in) investing activities		(35,777)	(699,970)	203,163
Financing Activities
Borrowings under term loan			0
Repayments under term loan		0	0	0
Borrowings under senior notes			0
Payment of debt issuance costs		0	0	0
Repayments under equipment financing facilities and other		0	0	0
Proceeds from secondary offering of common stock				0
Proceeds from issuance of convertible preferred stock			0
Payment of stock issuance costs			0	0
Payment of dividends on preferred stock		0	0
Proceeds from issuance of common stock related to equity awards		0	0	0
Taxes paid related to net share settlement of equity awards		0	0	0
Excess tax benefit from stock-based compensation				0
Intercompany activity		37,455	702,658	(206,739)
Net cash provided by (used in) financing activities		37,455	702,658	(206,739)
Effect of exchange rate changes on cash and cash equivalents		57	0	0
Net increase (decrease) in cash and cash equivalents		8,531	4,600	(4,194)
Cash and cash equivalents, beginning of period		(8,531)	(13,131)	(8,937)
Cash and cash equivalents, end of period		0	(8,531)	(13,131)
Revolving Lines of Credit [Member]
Financing Activities
Borrowings under revolving lines of credit		2,100,085	2,807,741	2,464,128
Repayments under revolving lines of credit		(2,113,982)	(2,707,741)	(2,833,230)
Revolving Lines of Credit [Member] | Reportable Legal Entities [Member] | Parent Company [Member]
Financing Activities
Borrowings under revolving lines of credit		0	0	0
Repayments under revolving lines of credit		0	0	0
Revolving Lines of Credit [Member] | Reportable Legal Entities [Member] | Guarantor Subsidiaries [Member]
Financing Activities
Borrowings under revolving lines of credit		2,049,500	2,766,447	2,445,084
Repayments under revolving lines of credit		(2,060,396)	(2,666,447)	(2,812,663)
Revolving Lines of Credit [Member] | Reportable Legal Entities [Member] | Non-Guarantor Subsidiaries [Member]
Financing Activities
Borrowings under revolving lines of credit		50,585	41,294	19,044
Repayments under revolving lines of credit		(53,586)	(41,294)	(20,567)
Revolving Lines of Credit [Member] | Eliminations and Other [Member]
Financing Activities
Borrowings under revolving lines of credit		0	0	0
Repayments under revolving lines of credit		$ 0	$ 0	$ 0

Allowance for Doubtful Accoun_3

Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Allowance For Doubtful Accounts [Abstract]
Balance at beginning of Year	$ 17,584	$ 11,829	$ 14,812
Charged to Operations	9,478	10,948	2,914
Write-offs	(13,967)	(5,193)	(5,897)
Balance at end of year	$ 13,095	$ 17,584	$ 11,829

Fair Value Measurement - Additi

Fair Value Measurement - Additional Information (Detail) - Fair Value, Inputs, Level 2 [Member] $ in Millions	12 Months Ended
	Sep. 30, 2019USD ($)
Senior Notes Due in 2023 [Member]
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Debt instrument maturity year	2023
Senior Notes Due in 2025 [Member]
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Debt instrument maturity year	2025
Carrying Value [Member] | Senior Notes Due in 2023 [Member]
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Senior notes	$ 300
Carrying Value [Member] | Senior Notes Due in 2025 [Member]
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Senior notes	1,300
Fair Value [Member] | Senior Notes Due in 2023 [Member]
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Senior notes	310.5
Fair Value [Member] | Senior Notes Due in 2025 [Member]
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Senior notes	$ 1,280

Employee Benefit Plans - Additi

Employee Benefit Plans - Additional Information (Details) $ in Millions	12 Months Ended
	Sep. 30, 2019USD ($)Employee	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)
Defined Contribution Plan Service Period	90 days
Description of Defined Contribution Pension and Other Postretirement Plans	The Company currently matches the first 50% of participant contributions limited to 6% of a participant’s gross compensation (maximum Company match is 3%).
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent	100.00%
Defined Contribution Plan Minimum Annual Contributions Per Employee Percent	1.00%
Defined First 50% of Participant Contribution Plan	50.00%
Defined Contribution Plan, Cost Recognized	$ 11.7	$ 11.8	$ 8.2
Pension Contributions	1	$ 0.2	$ 0.1
Multi-employer defined benefit plans aggregated expense	$ 2.6
Number of employees in collective bargaining agreements | Employee	42
Minimum [Member]
Defined Contribution Plan Qualifying Age	21
Maximum [Member]
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	6.00%
Defined Contribution Plan, Employer Matching Contribution, Percent of Match	3.00%

Financial Derivatives - Additio

Financial Derivatives - Additional Information (Detail)	Sep. 11, 2019USD ($)Agreement	Mar. 31, 2017USD ($)	Mar. 28, 2013USD ($)	Sep. 30, 2019USD ($)	Oct. 01, 2015USD ($)
Derivative [Line Items]
Number of interest rate swap agreements | Agreement	2
Derivative, notional amount			$ 213,800,000
Derivative amortized amount			$ 2,800,000
Derivative, fair value, net					$ 2,400,000
Unrealized gain (loss) on derivatives		$ 2,400,000
5-Year Swap [Member]
Derivative [Line Items]
Derivative, notional amount	$ 250,000,000
Term of derivative agreement	5 years
Derivative, maturity date	Aug. 30, 2024
Derivative, fixed interest rate	1.49%
Derivative fair value, net of tax				$ 1,100,000
3-Year Swap [Member]
Derivative [Line Items]
Derivative, notional amount	$ 250,000,000
Term of derivative agreement	3 years
Derivative, maturity date	Aug. 30, 2022
Derivative, fixed interest rate	1.50%
Derivative fair value, net of tax				$ 500,000
Interest Rate Swap Fixed Rate of 1.38% [Member]
Derivative [Line Items]
Derivative, maturity date			Mar. 31, 2017
Derivative, fixed interest rate			1.38%
Derivative amortization frequency				quarter

Financial Derivatives - Summary

Financial Derivatives - Summary of Combined Fair Values, Net of Tax of Interest Rate Derivative Instruments (Details) $ in Thousands	Sep. 30, 2019USD ($)
Designated as Hedging Instrument [Member] | Interest Rate Swaps [Member] | Fair Value, Inputs, Level 2 [Member] | Accrued Expenses [Member]
Derivative [Line Items]
Derivative fair value, net of tax	$ (1,612)

Financial Derivatives - Summa_2

Financial Derivatives - Summary of Amounts of Gain (Loss) on Interest Rate Derivative Instruments Recognized in Other Comprehensive Income (OCI) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Derivative [Line Items]
Gain (loss) on interest rate derivative instruments recognized in OCI	$ (1,612)	$ 0	$ 0
Designated as Hedging Instrument [Member] | Interest Rate Swaps [Member]
Derivative [Line Items]
Gain (loss) on interest rate derivative instruments recognized in OCI	$ (1,612)

Financial Derivatives - Summa_3

Financial Derivatives - Summary of Amounts of Gain (Loss) on Interest Rate Derivative Instruments Recognized in Interest Expense, Financing costs and Other (Detail) $ in Thousands	12 Months Ended
	Sep. 30, 2017USD ($)
Not Designated as Hedging Instrument [Member] | Interest Rate Swaps [Member]
Derivative [Line Items]
Gain (loss) on interest rate derivative instruments	$ (388)

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) - USD ($)	Oct. 28, 2019	Oct. 09, 2019	Dec. 31, 2019	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Subsequent Event [Line Items]
Loss on debt extinguishment				$ 0	$ 1,248,000	$ 0
Senior Notes, Matures November 2026 [Member] | Subsequent Events [Member]
Subsequent Event [Line Items]
Debt instrument, aggregate principal amount		$ 300,000,000
Debt instrument interest rate		4.50%
Debt instrument, issue price percentage		100.00%
Debt instrument maturity date		Nov. 15, 2026
Debt instrument, interest payable commencement date		May 15, 2020
Senior Notes, Matures October 2023 [Member]
Subsequent Event [Line Items]
Debt instrument interest rate				6.38%	6.38%
Debt instrument maturity date				Oct. 1, 2023	Oct. 1, 2023
Senior Notes, Matures October 2023 [Member] | Subsequent Events [Member]
Subsequent Event [Line Items]
Debt instrument interest rate	6.375%
Redemption of senior debt	$ 300,000,000
Debt redemption price percentage of principal amount	103.188%
Debt instrument, redemption description	On October 28, 2019, the Company used the net proceeds from the offering, together with cash on hand and available borrowings under its existing senior secured asset based revolving credit facility (the “2023 ABL”), to redeem all $300.0 million aggregate principal amount outstanding of its 6.375% senior secured notes due 2023 (the “2023 Senior Notes”) at a redemption price of 103.188%
Refinancing the Existing 2023 Senior Notes with Issuance of 2026 Senior Notes [Member] | Forecast [Member]
Subsequent Event [Line Items]
Loss on debt extinguishment			$ 14,700,000