Investments (Components Of Other Comprehensive Income Related To Available-For-Sale Securities) (Details) (USD $) In Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2011	Jul. 31, 2010	Jul. 31, 2011	Jul. 31, 2010
Investments
Accumulated OCI related to available-for-sale securities, beginning of the period	$ 17,967	$ 22,387	$ 17,871	$ 25,663
Unrealized gains on available-for-sale securities	928	1,275	1,089	2,713
Reclassification adjustment for gains included in net loss	(4,004)	(10,042)	(4,069)	(15,362)
Changes in accumulated OCI on available-for-sale securities, before tax	(3,076)	(8,767)	(2,980)	(12,649)
Other comprehensive income attributable to noncontrolling interest		45		24
Deferred income tax benefit		82		709
Changes in accumulated OCI on available-for-sale securities, net of tax	(3,076)	(8,640)	(2,980)	(11,916)
Accumulated OCI related to available-for-sale securities, end of the period	$ 14,891	$ 13,747	$ 14,891	$ 13,747