Financing Arrangements (Senior Notes) (Details) (USD $)			12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012 6.375% Senior Notes [Member]	Dec. 31, 2007 6.375% Senior Notes [Member]
Debt Instrument [Line Items]
Debt instrument, aggregate principal amount				$ 400,000,000
Debt instrument, stated interest rate (as a percentage)				6.375%
Debt instrument, maturity date				Dec. 31, 2017
Contingent payment of principal (as a percentage)			101.00%
Default on senior notes			0
Call feature (as a percentage)			100.00%
Number of days in year per debt terms			360 days
Number of months in year per debt terms			12 months
Number of days in month per debt terms			30 days
Debt instrument, benchmark for variable rate basis			Treasury rate
Treasury rate basis points (as a percentage)			0.30%
Senior note, failure to perform covenant			60 days
Threshold amount for noncompliance with senior note indenture			50,000,000
Minimum borrowed aggregate principal amount			50,000,000
Senior note, grace period for defaulted payment			30 days
Senior notes amount	$ 399,095,000	$ 398,890,000