Summary of Charges Recorded in Connection with Restructuring by Reportable Segment (Detail) - USD ($)	12 Months Ended
	May 31, 2020	May 31, 2019	May 31, 2018
Restructuring Cost And Reserve [Line Items]
Current Year Charges	$ 33,108,000	$ 42,310,000	$ 17,514,000
SPG reportable segment
Restructuring Cost And Reserve [Line Items]
Current Year Charges			0
2020 MAP to Growth
Restructuring Cost And Reserve [Line Items]
Current Year Charges	33,108,000	42,310,000	17,514,000
Cumulative Costs to Date	92,932,000
Total Expected Costs	110,919,000
2020 MAP to Growth | Severance and Benefit Costs
Restructuring Cost And Reserve [Line Items]
Current Year Charges	19,747,000	32,519,000	9,957,000
Cumulative Costs to Date	62,223,000
Total Expected Costs	72,423,000
2020 MAP to Growth | Facility Closure and Other Related Costs
Restructuring Cost And Reserve [Line Items]
Current Year Charges	8,548,000	8,195,000	6,184,000
Cumulative Costs to Date	22,927,000
Total Expected Costs	30,275,000
2020 MAP to Growth | Other Asset Write-offs
Restructuring Cost And Reserve [Line Items]
Current Year Charges	4,813,000	1,596,000	1,373,000
Cumulative Costs to Date	7,782,000
Total Expected Costs	8,221,000
2020 MAP to Growth | Construction Products Segment
Restructuring Cost And Reserve [Line Items]
Current Year Charges	8,726,000	11,598,000	4,187,000
Cumulative Costs to Date	24,511,000
Total Expected Costs	31,407,000
2020 MAP to Growth | Construction Products Segment | Severance and Benefit Costs
Restructuring Cost And Reserve [Line Items]
Current Year Charges	6,866,000	9,459,000	1,769,000
Cumulative Costs to Date	18,094,000
Total Expected Costs	22,243,000
2020 MAP to Growth | Construction Products Segment | Facility Closure and Other Related Costs
Restructuring Cost And Reserve [Line Items]
Current Year Charges	1,508,000	1,924,000	1,045,000
Cumulative Costs to Date	4,477,000
Total Expected Costs	7,140,000
2020 MAP to Growth | Construction Products Segment | Other Asset Write-offs
Restructuring Cost And Reserve [Line Items]
Current Year Charges	352,000	215,000	1,373,000
Cumulative Costs to Date	1,940,000
Total Expected Costs	2,024,000
2020 MAP to Growth | Performance Coatings Segment
Restructuring Cost And Reserve [Line Items]
Current Year Charges	9,094,000	9,839,000	400,000
Cumulative Costs to Date	19,333,000
Total Expected Costs	25,330,000
2020 MAP to Growth | Performance Coatings Segment | Severance and Benefit Costs
Restructuring Cost And Reserve [Line Items]
Current Year Charges	6,973,000	6,012,000	400,000
Cumulative Costs to Date	13,385,000
Total Expected Costs	17,073,000
2020 MAP to Growth | Performance Coatings Segment | Facility Closure and Other Related Costs
Restructuring Cost And Reserve [Line Items]
Current Year Charges	1,873,000	3,474,000
Cumulative Costs to Date	5,347,000
Total Expected Costs	7,349,000
2020 MAP to Growth | Performance Coatings Segment | Other Asset Write-offs
Restructuring Cost And Reserve [Line Items]
Current Year Charges	248,000	353,000
Cumulative Costs to Date	601,000
Total Expected Costs	908,000
2020 MAP to Growth | Consumer Segment
Restructuring Cost And Reserve [Line Items]
Current Year Charges	9,428,000	3,304,000	10,791,000
Cumulative Costs to Date	23,523,000
Total Expected Costs	25,749,000
2020 MAP to Growth | Consumer Segment | Severance and Benefit Costs
Restructuring Cost And Reserve [Line Items]
Current Year Charges	3,089,000	1,726,000	5,652,000
Cumulative Costs to Date	10,467,000
Total Expected Costs	11,493,000
2020 MAP to Growth | Consumer Segment | Facility Closure and Other Related Costs
Restructuring Cost And Reserve [Line Items]
Current Year Charges	2,245,000	1,553,000	5,139,000
Cumulative Costs to Date	8,937,000
Total Expected Costs	10,137,000
2020 MAP to Growth | Consumer Segment | Other Asset Write-offs
Restructuring Cost And Reserve [Line Items]
Current Year Charges	4,094,000	25,000
Cumulative Costs to Date	4,119,000
Total Expected Costs	4,119,000
2020 MAP to Growth | SPG reportable segment
Restructuring Cost And Reserve [Line Items]
Current Year Charges	4,633,000	7,585,000
Cumulative Costs to Date	12,218,000
Total Expected Costs	15,086,000
2020 MAP to Growth | SPG reportable segment | Severance and Benefit Costs
Restructuring Cost And Reserve [Line Items]
Current Year Charges	1,592,000	5,338,000
Cumulative Costs to Date	6,930,000
Total Expected Costs	8,267,000
2020 MAP to Growth | SPG reportable segment | Facility Closure and Other Related Costs
Restructuring Cost And Reserve [Line Items]
Current Year Charges	2,922,000	1,244,000
Cumulative Costs to Date	4,166,000
Total Expected Costs	5,649,000
2020 MAP to Growth | SPG reportable segment | Other Asset Write-offs
Restructuring Cost And Reserve [Line Items]
Current Year Charges	119,000	1,003,000
Cumulative Costs to Date	1,122,000
Total Expected Costs	1,170,000
2020 MAP to Growth | Corporate/Other Segment
Restructuring Cost And Reserve [Line Items]
Current Year Charges	1,227,000	9,984,000	2,136,000
Cumulative Costs to Date	13,347,000
Total Expected Costs	13,347,000
2020 MAP to Growth | Corporate/Other Segment | Severance and Benefit Costs
Restructuring Cost And Reserve [Line Items]
Current Year Charges	1,227,000	$ 9,984,000	$ 2,136,000
Cumulative Costs to Date	13,347,000
Total Expected Costs	$ 13,347,000