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Investment Securities Investment Securities Text Tags (Details) | 6 Months Ended |
--- | --- | ---
Sep. 30, 2018 USD ($) | Mar. 31, 2018 USD ($)
Schedule of Investments [Line Items] |  |
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions | 40 | 35
Available-for-sale | $ 92,195,000 | $ 60,709,000
Percentage Available-for-sale Securities | 81.30% |
Held-to-maturity | $ 11,545,000 | 12,075,000
Percentage Held-to-maturity Securities | 10.20% |
Equity securities | $ 9,642,000 | 0
Percentage Equity Securities | 8.50% |
Trading | $ 0 |
Cumulative Effect of New Accounting Principle | 0 |
Proceeds from Sale of Available-for-sale Securities | $ 0 |
Mortgage-backed securities |  |
Schedule of Investments [Line Items] |  |
Percentage Available-for-Sale, Continuos Unrealized Loss Position | 51.00% |
Number of AFS securities in Unrealized Loss Positions, greater than or equal to 12 months | 18 |
Held-to-maturity | $ 10,545,000 | 11,075,000
US Government Agency Securities |  |
Schedule of Investments [Line Items] |  |
Number of AFS securities in Unrealized Loss Positions, greater than or equal to 12 months | 3 |
Corporate Bonds |  |
Schedule of Investments [Line Items] |  |
Number of AFS securities in Unrealized Loss Positions, greater than or equal to 12 months | 5 |
Held-to-maturity | $ 1,000,000 | $ 1,000,000
Accumulated Other Comprehensive Loss |  |
Schedule of Investments [Line Items] |  |
Cumulative Effect of New Accounting Principle | $ 721,000 |

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- Definition Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109979856&loc=d3e26610-111562 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (aa) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563 + Details
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