Stock-Based Compensation (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jul. 31, 2013	Jul. 31, 2012	Jul. 31, 2013	Jul. 31, 2012
Amount of stock-based compensation costs and related deferred income tax benefit recognized in the financial statements
Total stock-based compensation costs	$ 4,058	$ 3,298	$ 9,310	$ 7,829
Less amount capitalized into qualifying real estate projects	(1,357)	(618)	(3,175)	(2,621)
Amount charged to operating expenses	2,701	2,680	6,135	5,208
Depreciation expense on capitalized stock-based compensation	240	207	480	414
Total stock-based compensation expense	2,941	2,887	6,615	5,622
Deferred income tax benefit	1,077	1,046	2,431	2,037
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	593	318	1,928	1,920
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	2,729	2,522	6,135	5,352
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	$ 458	$ 1,247	$ 557