Stock-Based Compensation (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Oct. 31, 2013	Oct. 31, 2012	Oct. 31, 2013	Oct. 31, 2012
Amount of stock-based compensation costs and related deferred income tax benefit recognized in the financial statements
Total stock-based compensation costs	$ 4,131	$ 3,488	$ 13,441	$ 11,317
Less amount capitalized into qualifying real estate projects	(1,590)	(1,410)	(4,765)	(4,031)
Amount charged to operating expenses	2,541	2,078	8,676	7,286
Depreciation expense on capitalized stock-based compensation	241	206	721	620
Total stock-based compensation expense	2,782	2,284	9,397	7,906
Deferred income tax benefit	1,009	819	3,440	2,856
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	673	590	2,601	2,510
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	2,722	2,481	8,857	7,833
Performance share costs [Member]
Amount of stock-based compensation costs and related deferred income tax benefit recognized in the financial statements
Total stock-based compensation costs	$ 736	$ 417	$ 1,983	$ 974