Summary of Significant Accounting Policies (Narrative) (Details) (USD $)	12 Months Ended
	Nov. 30, 2012	Nov. 30, 2011	Nov. 30, 2010
Significant Accounting Policies [Line Items]
Customer balance in excess of 10% of total revenues	0	0	0
Customer balance in excess of 10% of net accounts receivable	0	0
Depreciation of property and equipment	$ 14,931,000	$ 13,145,000	$ 13,414,000
Impairment of goodwill	0
Purchase price allocation period, maximum	1 year
Number of days after acquisition in which severance related costs are recorded as acquisition expenses	90 days
Gains (Losses) from foreign currency exchange	(700,000)	(1,900,000)	(1,900,000)
Advertising costs	$ 3,000,000	$ 2,400,000	$ 2,500,000