Business Segment Information (Supplemental Financial Information) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended				9 Months Ended
	Oct. 31, 2012		Oct. 31, 2011		Oct. 31, 2012		Oct. 31, 2011
Segment Reporting Information [Line Items]
Total revenue	$ 201,520		$ 199,364		$ 610,581		$ 570,655
Total costs and expenses	194,807		200,183		580,855		575,857
Income (loss) from operations	6,713		(819)		29,726		(5,202)
Stock-based compensation expense	7,743		7,572		21,207		25,080
Interest expense	(7,818)		(7,909)		(23,240)		(24,571)
Depreciation and amortization	(14,274)		(13,676)		(42,665)		(39,348)
Other non-cash items	$ (2)	[1]	$ (44)	[1]	$ (539)	[1]	$ (266)	[1]

[1] Other non-cash items consist of write-downs of property and equipment.