Business and geographic segments - Holding Percentage of Subsidiaries (Detail)	Mar. 31, 2023
Chemicals
Segment Reporting Information [Line Items]
Controlling interest in subsidiary	81.00%
Component Products
Segment Reporting Information [Line Items]
Controlling interest in subsidiary	87.00%
Real Estate Management And Development | BMI
Segment Reporting Information [Line Items]
Controlling interest in subsidiary	63.00%
Real Estate Management And Development | LandWell | Aggregate General And Limited Interests
Segment Reporting Information [Line Items]
Controlling interest in subsidiary	77.00%