Segment Data and Foreign Operations (Details) $ in Thousands	3 Months Ended						6 Months Ended	9 Months Ended
	Nov. 30, 2019 USD ($) segment		Aug. 31, 2019 USD ($) segment	Nov. 30, 2018 USD ($)		Aug. 31, 2018 USD ($)	Aug. 31, 2019 USD ($)	Aug. 31, 2019 USD ($)	May 31, 2019 segment
Segment data
Number of operating segments | segment	3		3						2
Revenue	$ 66,802			$ 72,503
Income before income taxes	10,071			11,808
Interest	55			204
Depreciation	1,053			1,238
Amortization	2,914			3,113
Total assets	326,041		$ 307,968				$ 307,968	$ 307,968
Exit costs related to facilities	649			260
Curtailment and settlement loss				200
Granite Falls Location
Segment data
Exit costs related to facilities	499						1,260
Anticipated future exit costs	200
Pawtucket, RI manufacturing facility
Segment data
Exit costs related to facilities				260		$ 1,272		0
Adhesives, Sealants and Additives
Segment data
Revenue	25,822			26,698
Income before income taxes	7,482			8,265
Interest	21			79
Depreciation	314			383
Amortization	2,337			2,340
Total assets	144,015		135,583				135,583	135,583
Industrial Tapes
Segment data
Revenue	30,124			33,462
Income before income taxes	6,637	[1]		6,538	[2]
Interest	25			84
Depreciation	401			456
Amortization	450			450
Total assets	70,327		77,085				77,085	77,085
Corrosion Protection and Waterproofing
Segment data
Revenue	10,856			12,343
Income before income taxes	3,964			4,466
Interest	9			41
Depreciation	154			175
Amortization	127			323
Total assets	31,221		32,478				32,478	32,478
Industrial Materials | Granite Falls Location
Segment data
Exit costs related to facilities	499
Industrial Materials | Pawtucket, RI manufacturing facility
Segment data
Exit costs related to facilities	260
Reportable segments
Segment data
Income before income taxes	18,083			19,269
Total assets	245,563		245,146				245,146	245,146
Corporate and common costs
Segment data
Income before income taxes	(8,012)	[3]		$ (7,461)	[4]
Total assets	80,478		$ 62,822				$ 62,822	$ 62,822
Engineering Studies related to Facility Consolidation and Rationalization Initiative
Segment data
Business development cost	$ 150

[1] Includes $499 in exit costs related to the movement of the pulling and detection business out of the Granite Falls, NC location and into the Hickory, NC location during the first quarter of fiscal 2020

[2] Includes $260 of expense related to the closure and exit of our Pawtucket, RI location recognized in the first quarter of fiscal 2019

[3] Includes $150 of expense related to exploratory IT work performed to assess potential future upgrades to our companywide ERP system

[4] Includes $200 of pension-related settlement costs due to the timing of lump-sum distributions