QUARTERLY INFORMATION (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended																12 Months Ended
	Oct. 31, 2011		Jul. 31, 2011		Apr. 30, 2011		Jan. 31, 2011		Oct. 31, 2010		Jul. 31, 2010		Apr. 30, 2010		Jan. 31, 2010		Oct. 31, 2011		Oct. 31, 2010		Oct. 31, 2009
Quarterly Financial Information [Line Items]
Revenues	$ 1,081,343		$ 1,076,247		$ 1,060,083		$ 1,029,169		$ 901,373		$ 869,029		$ 855,461		$ 869,884		$ 4,246,842		$ 3,495,747		$ 3,481,823
Gross profit	121,751		123,403		115,560		104,864		97,654		92,805		83,487		87,783		465,578		361,729
Other-than-temporary impairment losses on auction rate security:
Gross impairment losses									101				(101)								3,695
Impairements recognized in other comprehensive income									(101)				(26)						(127)		2,129
Income from continuing operations	18,182		27,911		14,200		8,405		21,438		20,973		8,623		12,836		68,698		63,870		55,490
(Loss) income from discontinued operations, net of taxes	(135)		(36)		(8)		(15)		368		(10)		(46)		(61)		(194)		251		(1,197)
Net income	$ 18,047		$ 27,875		$ 14,192		$ 8,390		$ 21,806		$ 20,963		$ 8,577		$ 12,775		$ 68,504		$ 64,121		$ 54,293
Net income per common share-Basic
Income from continuing operations	$ 0.34	[1]	$ 0.52	[1]	$ 0.27	[1]	$ 0.16	[1]	$ 0.42	[1]	$ 0.40	[1]	$ 0.16	[1]	$ 0.25	[1]	$ 1.29	[1]	$ 1.23	[1]	$ 1.08
Loss from discontinued operations		[1]		[1]		[1]		[1]		[1]		[1]		[1]		[1]		[1]		[1]	$ (0.02)
Net Income	$ 0.34	[1]	$ 0.52	[1]	$ 0.27	[1]	$ 0.16	[1]	$ 0.42	[1]	$ 0.40	[1]	$ 0.16	[1]	$ 0.25	[1]	$ 1.29	[1]	$ 1.23	[1]	$ 1.06
Net income per common share-Diluted
Income from continuing operations	$ 0.33	[1]	$ 0.51	[1]	$ 0.26	[1]	$ 0.16	[1]	$ 0.41	[1]	$ 0.40	[1]	$ 0.16	[1]	$ 0.24	[1]	$ 1.27	[1]	$ 1.21	[1]	$ 1.07
Loss from discontinued operations		[1]		[1]		[1]		[1]		[1]		[1]		[1]		[1]		[1]		[1]	$ (0.02)
Net Income	$ 0.33	[1]	$ 0.51	[1]	$ 0.26	[1]	$ 0.16	[1]	$ 0.41	[1]	$ 0.40	[1]	$ 0.16	[1]	$ 0.24	[1]	$ 1.27	[1]	$ 1.21	[1]	$ 1.05

[1] The sum of the quarterly per share amounts may not equal per share amounts reported for the year-to-date periods, due to the effects of rounding for each period.