Income Taxes - Classification of Deferred Tax Assets (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Sep. 30, 2011
Income Tax Disclosure [Line Items]
Total deferred tax assets	$ 551,082	$ 536,097
Deferred tax liabilities	(56,017)	(54,052)
Net deferred tax assets before valuation allowance	495,065	482,045
Valuation allowance	(488,217)	(479,285)
Net deferred tax assets	6,848	2,760
Subject To Annual Limitation [Member]
Income Tax Disclosure [Line Items]
Total deferred tax assets	87,441
Generally Not Subject to Annual Limitation [Member]
Income Tax Disclosure [Line Items]
Total deferred tax assets	345,839
Certain Components Likely To Be Subject To Annual Limitation [Member]
Income Tax Disclosure [Line Items]
Total deferred tax assets	$ 117,802