Nature of Business and Basis Of Presentation Correction of Prior Period Amounts (Income Statement) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended			9 Months Ended
	Aug. 31, 2012	Aug. 31, 2011		Aug. 31, 2012	Aug. 31, 2011
Provision for income taxes	$ 6,378	$ 3,919		$ 10,157	$ 21,536
Income from continuing operations	7,976	9,588		14,857	48,497
Net income	5,838	9,059		11,419	47,454
Basic
Continuing operations per share, basic	$ 0.13	$ 0.15		$ 0.24	$ 0.73
Net income per share	$ 0.09	$ 0.14		$ 0.18	$ 0.71
Diluted
Continuing operations per share, diluted	$ 0.12	$ 0.14		$ 0.23	$ 0.71
Net income per share	$ 0.09	$ 0.13		$ 0.18	$ 0.69
As Previously Reported [Member]
Provision for income taxes		4,377	[1]		21,909	[1]
Income from continuing operations		9,130	[1]		48,124	[1]
Net income		8,601	[1]		47,081	[1]
Basic
Continuing operations per share, basic		$ 0.14	[1]		$ 0.72	[1]
Net income per share		$ 0.13	[1]		$ 0.71	[1]
Diluted
Continuing operations per share, diluted		$ 0.14	[1]		$ 0.70	[1]
Net income per share		$ 0.13	[1]		$ 0.69	[1]
Adjustment [Member]
Provision for income taxes		(458)			(373)
Income from continuing operations		458			373
Net income		$ 458			$ 373
Basic
Continuing operations per share, basic		$ 0.01			$ 0.01
Net income per share		$ 0.01			$ 0.01
Diluted
Continuing operations per share, diluted		$ 0.01			$ 0.01
Net income per share		$ 0.01			$ 0.01

[1] The condensed consolidated statements of income for the three and nine months ended August 31, 2011 have been revised to reflect the impact of discontinued operations (Note 6).