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Investment Securities Investment Securities Text Tags (Details) | Sep. 30, 2017 USD ($) | Mar. 31, 2017 USD ($)
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Schedule of Investments [Line Items] |  |  |
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions |  | 31 | 33
Available-for-sale |  | $ 56,486,000 | $ 59,011,000
Percentage Available-for-sale Securities |  | 81.60% |
Held-to-maturity | [1] | $ 12,752,000 | 13,435,000
Percentage Held-to-maturity Securities |  | 18.40% |
Trading Securities |  | $ 0 |
Mortgage-backed securities |  |  |
Schedule of Investments [Line Items] |  |  |
Percentage Available-for-Sale, Continuos Unrealized Loss Position |  | 61.80% |
Number of AFS securities in Unrealized Loss Positions, greater than or equal to 12 months |  | 16 |
Available-for-sale |  | $ 34,690,000 | 36,703,000
Other investments |  |  |
Schedule of Investments [Line Items] |  |  |
Number of AFS securities in Unrealized Loss Positions, greater than or equal to 12 months |  | 1 |
Available-for-sale | [2] | $ 9,913,000 | 9,862,000
Corporate Bonds |  |  |
Schedule of Investments [Line Items] |  |  |
Number of AFS securities in Unrealized Loss Positions, greater than or equal to 12 months |  | 5 |
Available-for-sale |  | $ 5,013,000 | $ 4,964,000
[1] | * The carrying amount and amortized cost are the same for all held-to-maturity securities, as no OTTI has been recorded.
[2] | (1) Primarily comprised of an investment in a CRA fund with 95% of its underlying investments consisting of government and agency-backed securities.

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