Segments - Net Sales by Main Product Lines (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Oct. 31, 2023	Oct. 31, 2022	Oct. 31, 2023	Oct. 31, 2022
Revenue from external customers
Total net sales	$ 1,420,930	$ 1,430,979	$ 2,830,530	$ 2,790,532
Wallboard
Revenue from external customers
Total net sales	585,174	584,557	1,156,599	1,106,111
Complementary products
Revenue from external customers
Total net sales	428,319	408,669	854,529	804,497
Steel framing
Revenue from external customers
Total net sales	232,108	278,152	468,868	553,048
Ceilings
Revenue from external customers
Total net sales	$ 175,329	$ 159,601	$ 350,534	$ 326,876