Revenue - Summary of Revenues Disaggregated by Major Product and Sales Destination (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Feb. 28, 2022	Feb. 28, 2021	Feb. 28, 2022	Feb. 28, 2021
Disaggregation of Revenue [Line Items]
Revenues	$ 783,198	$ 600,111	$ 1,581,316	$ 1,092,218
Ferrous Revenues
Disaggregation of Revenue [Line Items]
Revenues	438,314	322,679	904,170	574,885
Nonferrous Revenues
Disaggregation of Revenue [Line Items]
Revenues	196,142	147,322	390,571	267,031
Steel Revenues
Disaggregation of Revenue [Line Items]
Revenues	116,196	99,191	219,434	187,605
Retail and Other Revenues
Disaggregation of Revenue [Line Items]
Revenues	32,546	30,919	67,141	62,697
Foreign
Disaggregation of Revenue [Line Items]
Revenues	435,471	332,197	906,644	600,596
Domestic
Disaggregation of Revenue [Line Items]
Revenues	$ 347,727	$ 267,914	$ 674,672	$ 491,622