Stock-Based Compensation (Details) (USD $) In Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2011	Jul. 31, 2010	Jul. 31, 2011	Jul. 31, 2010
Amount of stock-based compensation costs and related deferred income tax benefit recognized in the financial statements
Total stock-based compensation costs	$ 3,083	$ 3,779	$ 6,325	$ 9,046
Less amount capitalized into qualifying real estate projects	(1,493)	(2,092)	(1,924)	(4,585)
Amount charged to operating expenses	1,590	1,687	4,401	4,461
Depreciation expense on capitalized stock-based compensation	186	150	371	301
Total stock based compensation expense	1,776	1,837	4,772	4,762
Deferred income tax benefit	620	633	1,738	1,641
Employee Stock Option [Member]
Amount of stock-based compensation costs and related deferred income tax benefit recognized in the financial statements
Total stock-based compensation costs	806	1,362	995	4,214
Restricted Stock [Member]
Amount of stock-based compensation costs and related deferred income tax benefit recognized in the financial statements
Total stock-based compensation costs	$ 2,277	$ 2,417	$ 5,330	$ 4,832