Nature of Business and Basis Of Presentation Correction of Prior Period Amounts (Balance Sheet) (Details) (USD $) In Thousands, unless otherwise specified	Aug. 31, 2012	Nov. 30, 2011
Assets:
Other current assets	$ 26,863	$ 22,110
Deferred tax assets	10,105	13,458
Total current assets	471,755	407,911
Goodwill	252,735	256,211
Total assets	906,326	864,263
Liabilities and shareholders' equity:
Income taxes payable	4,171	6,048
Total current liabilities	217,466	226,144
Other noncurrent liabilities	2,574	4,857
Retained earnings, including accumulated other comprehensive loss	326,671	315,889
Total shareholders' equity	679,444	625,110
Total liabilities and shareholders' equity	906,326	864,263
As Previously Reported [Member]
Assets:
Other current assets		21,143	[1]
Deferred tax assets		14,291	[1]
Total current assets		407,777	[1]
Goodwill		257,824	[1]
Total assets		865,742	[1]
Liabilities and shareholders' equity:
Income taxes payable		11,412	[1]
Total current liabilities		231,508	[1]
Other noncurrent liabilities		3,782	[1]
Retained earnings, including accumulated other comprehensive loss		313,079	[1]
Total shareholders' equity		622,300	[1]
Total liabilities and shareholders' equity		865,742	[1]
Adjustment [Member]
Assets:
Other current assets		967
Deferred tax assets		(833)
Total current assets		134
Goodwill		(1,613)
Total assets		(1,479)
Liabilities and shareholders' equity:
Income taxes payable		(5,364)
Total current liabilities		(5,364)
Other noncurrent liabilities		1,075
Retained earnings, including accumulated other comprehensive loss		2,810
Total shareholders' equity		2,810
Total liabilities and shareholders' equity		$ (1,479)

[1] The condensed consolidated balance sheet as of November 30, 2011 was revised in previous filings to reflect purchase accounting measurement period adjustments (Note 7).