Income Taxes (Tax Carryforwards) (Details) $ in Thousands	Aug. 31, 2019 USD ($)
Domestic - state
Operating Loss Carryforwards [Line Items]
Income tax net operating loss carryforwards	$ 57,299
Tax credit carryforwards	3,313
Domestic - federal
Operating Loss Carryforwards [Line Items]
Tax credit carryforwards	39,784
Foreign
Operating Loss Carryforwards [Line Items]
Income tax net operating loss carryforwards	565,609
Tax credit carryforwards	$ 15,345