Segments - Net Sales by Main Product Lines (Details) - USD ($) $ in Thousands	3 Months Ended
	Jul. 31, 2025	Jul. 31, 2024
Revenue from external customers
Total net sales	$ 1,414,332	$ 1,448,456
Wallboard
Revenue from external customers
Total net sales	556,393	587,929
Complementary products
Revenue from external customers
Total net sales	440,457	443,513
Steel framing
Revenue from external customers
Total net sales	196,553	209,858
Ceilings
Revenue from external customers
Total net sales	$ 220,929	$ 207,156