Line of Credit (Narrative) (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Aug. 31, 2013
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Unsecured credit facility	$ 150.0
Additional borrowing capacity	75.0
Line of credit facility outstanding amount	0
Standby letters of credit [Member]
Line of Credit Facility [Line Items]
Additional borrowing capacity	25.0
Letters of credit outstanding amount	0.4
Swing line loans [Member]
Line of Credit Facility [Line Items]
Additional borrowing capacity	$ 20.0