Income Taxes (Narrative) (Details) (USD $)	12 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2009	Sep. 30, 2008
Income Taxes [Line Items]
Effective tax rate	(79.70%)	33.50%	35.90%
Earnings or loss before income taxes, foreign	$ 5,000,000	$ 5,000,000	$ 5,000,000
Income tax provision	83,000,000	105,300,000	156,900,000
Cumulative undistributed earnings	20,200,000
Deferred tax liability undistributed earning	7,100,000
Unrecognized tax benefit	5,600,000	4,900,000	2,000,000	1,600,000
Unrecognized tax reserve that would affect income tax rate	5,600,000
Business acquisition, purchase price allocation, preacquisition income tax contingency accrual		2,700,000
Parent Company [Member]
Income Taxes [Line Items]
Income tax provision	(83,100,000)	(32,700,000)	(15,300,000)
Foreign [Member]
Income Taxes [Line Items]
Operating loss carryforwards	56,700,000
Benefits of operating loss carryforwards	200,000	7,700,000	10,500,000
Operating loss carryforward, valuation allowance	700,000	1,300,000
Tax years that remain open to examination	six
State [Member]
Income Taxes [Line Items]
Operating loss carryforwards	50,000,000
Tax credit carryforward, amount	7,000,000
Canada [Member]
Income Taxes [Line Items]
Withholding tax paid	1,700,000
Internal Revenue Service (IRS) [Member]
Income Taxes [Line Items]
Tax credit carryforward, valuation allowance	3,000,000	3,200,000	2,300,000
Tax years that remain open to examination	September 30, 2007
Maximum [Member] | State [Member]
Income Taxes [Line Items]
Tax years that remain open to examination	six
Minimum [Member] | State [Member]
Income Taxes [Line Items]
Tax years that remain open to examination	two
2012-2016 [Member] | Foreign [Member]
Income Taxes [Line Items]
Operating loss carryforwards	2,700,000
2012-2016 [Member] | State [Member]
Income Taxes [Line Items]
Operating loss carryforwards	4,500,000
2017-2021 [Member] | State [Member]
Income Taxes [Line Items]
Operating loss carryforwards	13,900,000
2022-2031 [Member] | State [Member]
Income Taxes [Line Items]
Operating loss carryforwards	31,600,000
Tax Credit Carryforward No Expiration Date [Member] | State [Member]
Income Taxes [Line Items]
Tax credit carryforward, amount	3,000,000
2012-2025 [Member] | State [Member]
Income Taxes [Line Items]
Tax credit carryforward, amount	4,000,000
2028-2031 [Member] | Foreign [Member]
Income Taxes [Line Items]
Operating loss carryforwards	52,900,000
Other Liabilities [Member]
Income Taxes [Line Items]
Unrecognized tax benefit	4,700,000
Other Current Liabilities [Member] | State [Member]
Income Taxes [Line Items]
Unrecognized tax benefit	800,000
Operating Loss And Tax Credit Carryforwards [Member]
Income Taxes [Line Items]
Valuation allowance, amount			0
Operating Loss And Tax Credit Carryforwards [Member] | State [Member]
Income Taxes [Line Items]
Valuation allowance, amount				1,800,000
2012-2016 [Member] | Maximum [Member] | Foreign [Member]
Income Taxes [Line Items]
Operating loss carryforwards, expiration year	2016
2012-2016 [Member] | Maximum [Member] | State [Member]
Income Taxes [Line Items]
Operating loss carryforwards, expiration year	2016
2012-2016 [Member] | Minimum [Member] | Foreign [Member]
Income Taxes [Line Items]
Operating loss carryforwards, expiration year	2012
2012-2016 [Member] | Minimum [Member] | State [Member]
Income Taxes [Line Items]
Operating loss carryforwards, expiration year	2012
2017-2021 [Member] | Maximum [Member] | State [Member]
Income Taxes [Line Items]
Operating loss carryforwards, expiration year	2021
2017-2021 [Member] | Minimum [Member] | State [Member]
Income Taxes [Line Items]
Operating loss carryforwards, expiration year	2017
2022-2031 [Member] | Maximum [Member] | State [Member]
Income Taxes [Line Items]
Operating loss carryforwards, expiration year	2031
2022-2031 [Member] | Minimum [Member] | State [Member]
Income Taxes [Line Items]
Operating loss carryforwards, expiration year	2022
2012-2025 [Member] | Maximum [Member] | State [Member]
Income Taxes [Line Items]
Tax credit carryforward, expiration year	2025
2012-2025 [Member] | Minimum [Member] | State [Member]
Income Taxes [Line Items]
Tax credit carryforward, expiration year	2012
2027-2031 [Member] | Maximum [Member] | Foreign [Member]
Income Taxes [Line Items]
Operating loss carryforwards, expiration year	2031
2027-2031 [Member] | Minimum [Member] | Foreign [Member]
Income Taxes [Line Items]
Operating loss carryforwards, expiration year	2027
Carry Forwards Expiration Dates None [Member] | Foreign [Member]
Income Taxes [Line Items]
Operating loss carryforwards	$ 1,000,000