Investment Securities Text Tag (Details)	12 Months Ended
Mar. 31, 2017 USD ($)	Mar. 31, 2018 USD ($)
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Amortized Cost Basis	$ 60,951,000	$ 63,435,000
Available-for-sale Securities	59,011,000	$ 60,709,000
Percentage Available-for-sale Securities		83.40%
Held-to-maturity	13,435,000	$ 12,075,000
Percentage Held-to-maturity Securities		16.60%
Debt Securities, Trading, and Equity Securities, FV-NI		$ 0
Proceeds from Sale and Maturity of Held-to-maturity Securities	$ 0
Financial Instruments, Owned and Pledged as Collateral, at Fair Value		$ 27,700,000
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions	33	35
Mortgage-Backed Securities
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Amortized Cost Basis	$ 37,870,000	$ 33,434,000
Percentage Available-for-Sale, Continuous Unrealized Loss Position		52.80%
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Greater than or Equal to One Year		17
Available-for-sale Securities	36,658,000	$ 31,827,000
Held-to-maturity	12,435,000	11,075,000
US Government Agency Securities
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Amortized Cost Basis	7,574,000	$ 14,490,000
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Greater than or Equal to One Year		3
Available-for-sale Securities	7,482,000	$ 14,232,000
Other investments
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Amortized Cost Basis	10,403,000	$ 10,433,000
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Greater than or Equal to One Year		1
Available-for-sale Securities	9,907,000	$ 9,784,000
Corporate Bonds
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Amortized Cost Basis	5,104,000	$ 5,078,000
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Greater than or Equal to One Year		5
Available-for-sale Securities	4,964,000	$ 4,866,000
Held-to-maturity	$ 1,000,000	$ 1,000,000

Percentage Available-for-sale Securities

No definition available.

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- Definition

Percentage Available-for-Sale, Continuous Unrealized Loss Position

+ References

No definition available.

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- Definition

Percentage Held-to-maturity Securities

+ References

No definition available.

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- Definition

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

+ References

No definition available.

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- Definition

This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

+ References

No definition available.

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- Definition

Number of investment positions in available-for-sale investments in a continuous unrealized loss position for which an other-than-temporary impairment (OTTI) has not been recognized in the income statement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (b)(3)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27290-111563

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- Definition

Number of investment positions in available-for-sale investments that have been in a continuous unrealized loss position for greater than or equal to a year for which an other-than-temporary impairment (OTTI) has not been recognized in the income statement.

+ References

No definition available.

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- Definition

The fair value as of the balance sheet date of financial instruments and other positions owned by the entity and pledged to counterparties as collateral, including: (1) mortgages, mortgage-backed and asset backed securities; (2) US government and agency obligations; (3) state and municipal government obligations; (4) other sovereign government debt; (5) corporate obligations; (6) corporate equities; (7) principal investments; (8) derivative contracts; and (9) physical commodities.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 30
-Section 45
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-Paragraph 1A
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- Definition

Amount of investment in debt security measured at amortized cost (held-to-maturity).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 1
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- Definition

Amount of cash inflow from the sale or maturity of long-term held-to-maturity securities.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Amount of investment in debt security measured at fair value with change in fair value recognized in net income (trading) and investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
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-SubTopic 210
-Section S99
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