Income Taxes - Classification of Deferred Tax Assets (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Income Tax Disclosure [Line Items]
Total deferred tax assets	$ 491,547	$ 546,773
Deferred tax liabilities	(43,496)	(54,257)
Net deferred tax assets before valuation allowance	448,051	492,516
Valuation allowance	(445,228)	(487,263)
Deferred tax assets, net	2,823	5,253
Subject to annual limitation
Income Tax Disclosure [Line Items]
Total deferred tax assets	102,207
Generally not subject to annual limitation
Income Tax Disclosure [Line Items]
Total deferred tax assets	348,435
Certain components likely to be subject to annual limitation
Income Tax Disclosure [Line Items]
Total deferred tax assets	$ 40,905