Accumulated Other Comprehensive Loss (Details) (USD $)	9 Months Ended
	Aug. 31, 2013	Nov. 30, 2012
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance, December 1, 2012	$ (10,764,000)
Other comprehensive income (loss) before reclassification, net of tax	(3,912,000)
Amounts reclassified from accumulated other comprehensive income	0
Balance, August 31, 2013	(14,676,000)
Foreign Currency Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance, December 1, 2012	(8,183,000)
Other comprehensive income (loss) before reclassification, net of tax	(4,010,000)
Amounts reclassified from accumulated other comprehensive income	0
Balance, August 31, 2013	(12,193,000)
Unrealized Gains (Losses) on Investments [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance, December 1, 2012	(2,581,000)
Other comprehensive income (loss) before reclassification, net of tax	98,000
Amounts reclassified from accumulated other comprehensive income	0
Balance, August 31, 2013	(2,483,000)
Tax effect on accumulated unrealized losses on investments	$ 1,400,000	$ 1,500,000