Annual and transition report of foreign private issuers pursuant to Section 13 or 15(d)

Operating Segment Information and Concentrations of Risk - Summary of Gross Sales by Major Customers (Details)

v3.21.1
Operating Segment Information and Concentrations of Risk - Summary of Gross Sales by Major Customers (Details) - Sales Revenue, Net - USD ($)
$ in Millions
12 Months Ended
Mar. 31, 2021
Mar. 31, 2020
Mar. 31, 2019
Geographic Concentration Risk | Non-US      
Segment Reporting Information [Line Items]      
Gross sales percentage (as percent) 33.00% 34.00% 36.00%
Customer A | North America Fiber Cement | Customer Concentration Risk      
Segment Reporting Information [Line Items]      
Net sales $ 347.3 $ 306.0 $ 260.5
Gross sales percentage (as percent) 12.00% 12.00% 10.40%