Revenue - Schedule of Disaggregated Revenues (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	May 31, 2025	May 31, 2024	May 31, 2025	May 31, 2024
Disaggregation of Revenue [Line Items]
Total sales	$ 1,178.6	$ 968.1	$ 3,136.5	$ 2,808.7
Operating Segments \| Acuity Brands Lighting
Disaggregation of Revenue [Line Items]
Total sales	923.2	898.5	2,649.8	2,618.4
Operating Segments \| Acuity Intelligent Spaces
Disaggregation of Revenue [Line Items]
Total sales	264.1	75.7	509.1	208.0
Operating Segments \| Independent sales network \| Acuity Brands Lighting
Disaggregation of Revenue [Line Items]
Total sales	685.3	637.1	1,944.4	1,874.6
Operating Segments \| Direct sales network \| Acuity Brands Lighting
Disaggregation of Revenue [Line Items]
Total sales	101.5	97.0	306.1	287.4
Operating Segments \| Retail sales \| Acuity Brands Lighting
Disaggregation of Revenue [Line Items]
Total sales	41.4	45.7	127.3	147.7
Operating Segments \| Corporate accounts \| Acuity Brands Lighting
Disaggregation of Revenue [Line Items]
Total sales	35.5	60.5	103.8	140.1
Operating Segments \| OEM and other \| Acuity Brands Lighting
Disaggregation of Revenue [Line Items]
Total sales	59.5	58.2	168.2	168.6
Eliminations
Disaggregation of Revenue [Line Items]
Total sales	$ (8.7)	$ (6.1)	$ (22.4)	$ (17.7)