Cover - shares	6 Months Ended
	Jun. 30, 2022	Jul. 31, 2022
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2022
Document Transition Report	false
Entity File Number	000-50924
Entity Registrant Name	BEACON ROOFING SUPPLY, INC.
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
Title of 12(b) Security	Common Stock, $0.01 par value
Trading Symbol	BECN
Security Exchange Name	NASDAQ
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 Common Stock, Shares Outstanding		65,002,001
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Document Fiscal Period Focus	Q2
Document Fiscal Year Focus	2022
Entity Central Index Key	0001124941