Leases (Narrative) (Details) - USD ($)	3 Months Ended
	Nov. 30, 2019	Sep. 01, 2019	Aug. 31, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Short term lease	$ 0
Assets	317,491,000		$ 302,662,000
Liabilities	171,499,000		$ 157,187,000
Operating lease right-of-use assets	8,734,000
Lease expense	500,000
Lease payments	$ 500,000
Weighted-average discount rate	3.10%
Weighted-average lease term	7 years 4 months 20 days
Accounting Standards Update 2016-02 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Assets		$ 9,000,000.0
Liabilities		$ 9,000,000
Operating lease right-of-use assets	$ 0