Summary of Charges Recorded in Connection with Restructuring by Reportable Segment (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Nov. 30, 2020	Nov. 30, 2019	Nov. 30, 2020	Nov. 30, 2019
Restructuring Cost And Reserve [Line Items]
Current Year Charges	$ 4,918	$ 4,801	$ 9,151	$ 11,423
MAP to Growth
Restructuring Cost And Reserve [Line Items]
Current Year Charges	4,918	4,801	9,151	11,423
Cumulative Costs to Date	102,083		102,083
Total Expected Costs	112,402		112,402
MAP to Growth | Severance and Benefit Costs
Restructuring Cost And Reserve [Line Items]
Current Year Charges	2,135	2,729	4,612	6,515
Cumulative Costs to Date	66,835		66,835
Total Expected Costs	69,894		69,894
MAP to Growth | Other Restructuring Costs
Restructuring Cost And Reserve [Line Items]
Current Year Charges	495	251	730	315
Cumulative Costs to Date	8,512		8,512
Total Expected Costs	9,177		9,177
MAP to Growth | Facility Closure and Other Related Costs
Restructuring Cost And Reserve [Line Items]
Current Year Charges	2,288	1,821	3,809	4,593
Cumulative Costs to Date	26,736		26,736
Total Expected Costs	33,331		33,331
MAP to Growth | Construction Products Segment
Restructuring Cost And Reserve [Line Items]
Current Year Charges	1,896	1,596	2,481	2,444
Cumulative Costs to Date	26,992		26,992
Total Expected Costs	29,705		29,705
MAP to Growth | Construction Products Segment | Severance and Benefit Costs
Restructuring Cost And Reserve [Line Items]
Current Year Charges	1,394	1,447	1,574	1,607
Cumulative Costs to Date	19,668		19,668
Total Expected Costs	20,568		20,568
MAP to Growth | Construction Products Segment | Other Restructuring Costs
Restructuring Cost And Reserve [Line Items]
Current Year Charges	62	39	99	39
Cumulative Costs to Date	2,039		2,039
Total Expected Costs	2,634		2,634
MAP to Growth | Construction Products Segment | Facility Closure and Other Related Costs
Restructuring Cost And Reserve [Line Items]
Current Year Charges	440	110	808	798
Cumulative Costs to Date	5,285		5,285
Total Expected Costs	6,503		6,503
MAP to Growth | Performance Coatings Segment
Restructuring Cost And Reserve [Line Items]
Current Year Charges	1,542	1,239	2,898	3,848
Cumulative Costs to Date	22,231		22,231
Total Expected Costs	25,443		25,443
MAP to Growth | Performance Coatings Segment | Severance and Benefit Costs
Restructuring Cost And Reserve [Line Items]
Current Year Charges	802	431	1,841	2,931
Cumulative Costs to Date	15,226		15,226
Total Expected Costs	16,714		16,714
MAP to Growth | Performance Coatings Segment | Other Restructuring Costs
Restructuring Cost And Reserve [Line Items]
Current Year Charges	184	172	213	172
Cumulative Costs to Date	814		814
Total Expected Costs	824		824
MAP to Growth | Performance Coatings Segment | Facility Closure and Other Related Costs
Restructuring Cost And Reserve [Line Items]
Current Year Charges	556	636	844	745
Cumulative Costs to Date	6,191		6,191
Total Expected Costs	7,905		7,905
MAP to Growth | Consumer Segment
Restructuring Cost And Reserve [Line Items]
Current Year Charges	985	1,124	2,470	2,407
Cumulative Costs to Date	25,993		25,993
Total Expected Costs	28,453		28,453
MAP to Growth | Consumer Segment | Severance and Benefit Costs
Restructuring Cost And Reserve [Line Items]
Current Year Charges	(4)	780	786	1,547
Cumulative Costs to Date	11,253		11,253
Total Expected Costs	11,253		11,253
MAP to Growth | Consumer Segment | Other Restructuring Costs
Restructuring Cost And Reserve [Line Items]
Current Year Charges	204		302
Cumulative Costs to Date	4,421		4,421
Total Expected Costs	4,481		4,481
MAP to Growth | Consumer Segment | Facility Closure and Other Related Costs
Restructuring Cost And Reserve [Line Items]
Current Year Charges	785	344	1,382	860
Cumulative Costs to Date	10,319		10,319
Total Expected Costs	12,719		12,719
MAP to Growth | Specialty Products Group ("SPG") Segment
Restructuring Cost And Reserve [Line Items]
Current Year Charges	495	819	1,302	2,708
Cumulative Costs to Date	13,520		13,520
Total Expected Costs	15,454		15,454
MAP to Growth | Specialty Products Group ("SPG") Segment | Severance and Benefit Costs
Restructuring Cost And Reserve [Line Items]
Current Year Charges	(57)	48	411	414
Cumulative Costs to Date	7,341		7,341
Total Expected Costs	8,012		8,012
MAP to Growth | Specialty Products Group ("SPG") Segment | Other Restructuring Costs
Restructuring Cost And Reserve [Line Items]
Current Year Charges	45	40	116	104
Cumulative Costs to Date	1,238		1,238
Total Expected Costs	1,238		1,238
MAP to Growth | Specialty Products Group ("SPG") Segment | Facility Closure and Other Related Costs
Restructuring Cost And Reserve [Line Items]
Current Year Charges	507	731	775	2,190
Cumulative Costs to Date	4,941		4,941
Total Expected Costs	6,204		6,204
MAP to Growth | Corporate/Other Segment
Restructuring Cost And Reserve [Line Items]
Current Year Charges		23		16
Cumulative Costs to Date	13,347		13,347
Total Expected Costs	13,347		13,347
MAP to Growth | Corporate/Other Segment | Severance and Benefit Costs
Restructuring Cost And Reserve [Line Items]
Current Year Charges		$ 23		$ 16
Cumulative Costs to Date	13,347		13,347
Total Expected Costs	$ 13,347		$ 13,347