Summary of Significant Accounting Policies Marketable Securities (Details) (USD $)	12 Months Ended
Jan. 31, 2015	Jan. 31, 2014
Marketable Securities [Abstract]
Gross Unrealized Gains	$ 5,123,000	$ 4,889,000
Gross Unrealized Losses	$ 1,908,000	$ 804,000

Amount of unrealized gain before deducting unrealized loss on investments in debt and equity securities classified as available-for-sale securities.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27161-111563

Name:	us-gaap_AvailableForSaleSecuritiesGrossUnrealizedGains
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration