Income Taxes (Narrative) (Details) - USD ($)	4 Months Ended	8 Months Ended	12 Months Ended
	Dec. 31, 2017	Aug. 31, 2018	Aug. 31, 2019	Aug. 31, 2018	Aug. 31, 2017	Aug. 31, 2016	Aug. 31, 2015
Income Taxes [Line Items]
U.S. federal corporate income tax rate	35.00%	21.00%		25.70%	35.00%	35.00%
Deferred income tax assets and liabilities resulting from U.S. tax reform				$ 517,000	$ (688,000)	$ (5,456,000)
Provisional deemed repatriation tax expense				1,700,000
Tax Cuts and Jobs Act, Incomplete Accounting, Change in Tax Rate, Deferred Tax Liability				0
Valuation allowance		$ 3,562,000		3,562,000	2,804,000
Unrecognized tax benefits that would impact effective tax rate		$ 1,100,000		1,100,000	1,100,000
Accrued interest and penalties				$ 1,000,000	$ 800,000
Maximum [Member]
Income Taxes [Line Items]
Percentage of Recognized largest amount benefit realized upon settlement		50.00%		50.00%
Statutes of limitation range period				5 years
Minimum [Member]
Income Taxes [Line Items]
Statutes of limitation range period				3 years
Filtration Business [Member]
Income Taxes [Line Items]
Valuation allowance		$ 1,200,000		$ 1,200,000
Capital loss on sale of business		5,100,000		5,100,000
U.S. [Member]
Income Taxes [Line Items]
Deferred income tax assets and liabilities resulting from U.S. tax reform				800,000
Certain Foreign Tax Jurisdiction [Member]
Income Taxes [Line Items]
Valuation allowance		$ 2,400,000		$ 2,400,000			$ 2,900,000
Scenario, Plan [Member]
Income Taxes [Line Items]
U.S. federal corporate income tax rate			21.00%