Fair Value Measurement (Details) - USD ($) $ in Thousands	Oct. 31, 2015	Jan. 31, 2015
Investment securities classified as held to maturity
Amortized Cost	$ 64,724	$ 38,297
Total Fair Market Value	64,751	38,330
Short-term Investments
Investment securities classified as held to maturity
Amortized Cost	34,142	15,850
Gross Unrealized Gains	12	9
Total Fair Market Value	34,154	15,859
Short-term Investments \| Obligations of the U.S. Treasury \| Fair Value, Inputs, Level 1
Investment securities classified as held to maturity
Amortized Cost	8,775	8,780
Gross Unrealized Gains	10	9
Total Fair Market Value	8,785	8,789
Short-term Investments \| Obligations of states and municipalities \| Fair Value, Inputs, Level 2
Investment securities classified as held to maturity
Amortized Cost	2,928	2,074
Gross Unrealized Gains	2
Total Fair Market Value	2,930	2,074
Short-term Investments \| Bank certificates of deposit \| Fair Value, Inputs, Level 2
Investment securities classified as held to maturity
Amortized Cost	22,439	4,996
Total Fair Market Value	22,439	4,996
Long Term Investments
Investment securities classified as held to maturity
Amortized Cost	30,582	22,447
Gross Unrealized Gains	15	24
Total Fair Market Value	30,597	22,471
Long Term Investments \| Obligations of the U.S. Treasury \| Fair Value, Inputs, Level 1
Investment securities classified as held to maturity
Amortized Cost	20,001	7,543
Gross Unrealized Gains	15	24
Total Fair Market Value	20,016	7,567
Long Term Investments \| Bank certificates of deposit \| Fair Value, Inputs, Level 2
Investment securities classified as held to maturity
Amortized Cost	10,581	14,904
Total Fair Market Value	$ 10,581	$ 14,904

Amount after other than temporary impairment (OTTI) accretion, of investments in debt securities classified as held-to-maturity.

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

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-Name Accounting Standards Codification

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