Lines of Credit and Financing Arrangements (Details Textual 1) (USD $)	3 Months Ended		9 Months Ended			3 Months Ended
	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014 Revolving Credit Facility [Member]	Sep. 30, 2014 Maximum [Member]	Sep. 30, 2014 Minimum [Member]	Mar. 31, 2014 Revolving Credit Facility [Member] Maximum [Member]	Mar. 31, 2014 Revolving Credit Facility [Member] Minimum [Member]
Line of Credit Facility [Line Items]
Maximum securitization, amount				$ 220,000,000	$ 160,000,000
Maximum securitization as percentage of net pool balance		100.00%
Program fee	0.60%
Average floating commercial paper rate	0.77%	0.78%
Unused fee	101.00%
Fixed rate of agreement	0.30%
Domestic Revolving Credit Facility			650,000,000
Borrowings under Domestic Revolving Credit Facility			149,000,000
Committed standby letters of credit			27,200,000
Available for future borrowings			473,800,000
Extended maturity date			Oct. 31, 2016
Maximum increase in borrowings under Domestic Revolving Credit Facility			$ 100,000,000
Indebtedness to adjusted EBITDA ratio						3.5
Cash flow to net interest expense ratio							3.0