Investments (Components Of Other Comprehensive Income Related To Available-For-Sale Securities) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Oct. 31, 2011	Oct. 31, 2010	Oct. 31, 2011	Oct. 31, 2010
Investments [Abstract]
Accumulated OCI related to available-for-sale securities, beginning of the period	$ 14,891	$ 13,747	$ 17,871	$ 25,663
Unrealized gains on available-for-sale securities	(1,376)	1,202	(287)	3,915
Reclassification adjustment for gains included in net income/(loss)	(87)	(57)	(4,156)	(15,419)
Changes in accumulated OCI on available-for-sale securities, before tax	(1,463)	1,145	(4,443)	(11,504)
Other comprehensive income attributable to noncontrolling interest				24
Deferred income tax benefit		3		712
Changes in accumulated OCI on available-for-sale securities, net of tax	(1,463)	1,148	(4,443)	(10,768)
Accumulated OCI related to available-for-sale securities, end of the period	$ 13,428	$ 14,895	$ 13,428	$ 14,895