Pensions and Other Postretirement Benefits (Details) - USD ($) $ in Thousands	3 Months Ended
	Nov. 30, 2019	Nov. 30, 2018
Components of net periodic benefit cost
Service cost	$ 73	$ 73
Interest cost	113	178
Expected return on plan assets	(98)	(112)
Amortization of prior service cost	1	1
Amortization of accumulated loss	174	118
Curtailment and settlement loss		200
Net periodic benefit cost	263	458
Employer contribution	$ 392	$ 389