Pensions and Other Postretirement Benefits (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Feb. 29, 2020	Feb. 28, 2019	Feb. 29, 2020	Feb. 28, 2019
Components of net periodic benefit cost
Service cost	$ 74	$ 73	$ 147	$ 146
Interest cost	113	178	226	356
Expected return on plan assets	(98)	(109)	(196)	(221)
Amortization of prior service cost	1	1	2	2
Amortization of accumulated loss	174	119	348	237
Curtailment and settlement loss		273		473
Net periodic benefit cost	$ 264	$ 535	527	993
Employer contribution			$ 785	$ 784