Stock-Based Compensation (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jul. 31, 2012	Jul. 31, 2011	Jul. 31, 2012	Jul. 31, 2011
Amount of stock-based compensation costs and related deferred income tax benefit recognized in the financial statements
Total stock-based compensation costs	$ 3,298	$ 3,083	$ 7,829	$ 6,325
Less amount capitalized into qualifying real estate projects	(618)	(1,493)	(2,621)	(1,924)
Amount charged to operating expenses	2,680	1,590	5,208	4,401
Depreciation expense on capitalized stock-based compensation	207	186	414	371
Total stock-based compensation expense	2,887	1,776	5,622	4,772
Deferred income tax benefit	1,046	620	2,037	1,738
Stock option costs [Member]
Amount of stock-based compensation costs and related deferred income tax benefit recognized in the financial statements
Total stock-based compensation costs	318	806	1,920	995
Restricted stock costs [Member]
Amount of stock-based compensation costs and related deferred income tax benefit recognized in the financial statements
Total stock-based compensation costs	2,522	2,277	5,352	5,330
Performance Shares [Member]
Amount of stock-based compensation costs and related deferred income tax benefit recognized in the financial statements
Total stock-based compensation costs	$ 458	$ 0	$ 557	$ 0