Segments - Net Sales by Main Product Lines (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Oct. 31, 2024	Oct. 31, 2023	Oct. 31, 2024	Oct. 31, 2023
Revenue from external customers
Total net sales	$ 1,470,776	$ 1,420,930	$ 2,919,232	$ 2,830,530
Wallboard
Revenue from external customers
Total net sales	582,119	585,174	1,170,048	1,156,599
Complementary products
Revenue from external customers
Total net sales	466,828	428,319	910,341	854,529
Steel framing
Revenue from external customers
Total net sales	217,388	232,108	427,246	468,868
Ceilings
Revenue from external customers
Total net sales	$ 204,441	$ 175,329	$ 411,597	$ 350,534