Income Taxes - Narrative (Details) - USD ($)	12 Months Ended
	Aug. 31, 2015	Aug. 31, 2014	Aug. 31, 2013
Operating Loss Carryforwards [Line Items]
Federal	$ 29,348,000	$ (23,444,000)	$ 92,102,000
Income (Loss) from Continuing Operations before Income Taxes, Domestic	800,000,000	1,200,000,000	1,100,000,000
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense	0	0	200,000
Operating Loss Carryforwards	431,400,000
Deferred Tax Assets, Operating Loss Carryforwards, Subject to Expiration	293,900,000
Change in valuation allowance for deferred tax asset	8,800,000
Current State and Local Tax Expense (Benefit)	3,891,000	31,203,000	11,805,000
Unrecognized Tax Benefits, Increase Resulting from Prior Period Tax Positions	0	35,718,000	$ 0
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued	0	0
Minimum
Operating Loss Carryforwards [Line Items]
Unrecognized Tax Benefits, Increase Resulting from Prior Period Tax Positions	0
Maximum
Operating Loss Carryforwards [Line Items]
Unrecognized Tax Benefits, Increase Resulting from Prior Period Tax Positions	36,500,000
Domestic Tax Authority [Member]
Operating Loss Carryforwards [Line Items]
Federal	30,800,000
State and Local Jurisdiction [Member]
Operating Loss Carryforwards [Line Items]
Current State and Local Tax Expense (Benefit)	19,300,000
Current assets
Operating Loss Carryforwards [Line Items]
Net deferred tax assets	85,000,000	86,500,000
Other Assets [Member]
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Net of Valuation Allowance, Noncurrent	1,600,000	2,600,000
Foreign tax credit
Operating Loss Carryforwards [Line Items]
Tax credit carryforward, amount	8,000,000
Alternative Minimum Tax Credit [Member]
Operating Loss Carryforwards [Line Items]
Tax credit carryforward, amount	5,600,000
General Business Tax Credit Carryforward [Member]
Operating Loss Carryforwards [Line Items]
Tax credit carryforward, amount	55,700,000
State tax credits [Member]
Operating Loss Carryforwards [Line Items]
Tax credit carryforward, amount	62,200,000
NCRA [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	62,200,000	$ 63,400,000
Change in valuation allowance for deferred tax asset	$ 20,100,000