Accumulated Other Comprehensive Loss (Details) (USD $)	9 Months Ended
	Aug. 31, 2014	Nov. 30, 2013
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance, December 1, 2013	$ (11,659,000)
Other comprehensive income before reclassifications, net of tax	909,000
Amounts reclassified from accumulated other comprehensive loss to realized losses included in earnings, net of tax	1,617,000
Balance, August 31, 2014	(9,133,000)
Foreign Currency Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance, December 1, 2013	(9,249,000)
Other comprehensive income before reclassifications, net of tax	93,000
Amounts reclassified from accumulated other comprehensive loss to realized losses included in earnings, net of tax	0
Balance, August 31, 2014	(9,156,000)
Unrealized Gains (Losses) on Investments [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance, December 1, 2013	(2,410,000)
Other comprehensive income before reclassifications, net of tax	816,000
Amounts reclassified from accumulated other comprehensive loss to realized losses included in earnings, net of tax	1,617,000
Balance, August 31, 2014	23,000
Tax effect on accumulated unrealized losses on investments		$ 1,400,000