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

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27232-111563

+ Details

Name:	us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27232-111563

+ Details

Name:	us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount, before other-than-temporary impairment (OTTI) accretion, of investment in debt securities measured at amortized cost (held-to-maturity).

+ References

No definition available.

+ Details

Name:	us-gaap_HeldToMaturitySecuritiesAmortizedCostBeforeOtherThanTemporaryImpairment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (aa)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27232-111563

+ Details

Name:	us-gaap_HeldToMaturitySecuritiesFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_USGovernmentAgenciesDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_USStatesAndPoliticalSubdivisionsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_MortgageBackedSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_CorporateDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Note 3 - Securities - Securities Held-to-maturity (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Securities held-to-maturity, amortized costs		$ 118,662	$ 127,164
Securities held-to-maturity, gross unrealized gains			3,122
Securities held-to-maturity, gross unrealized losses			173
Securities held to maturity, fair value	$ 0	$ 119,790	130,113
US Government Agencies Debt Securities [Member]
Securities held-to-maturity, amortized costs			3,934
Securities held-to-maturity, gross unrealized gains			167
Securities held-to-maturity, gross unrealized losses
Securities held to maturity, fair value			4,101
US States and Political Subdivisions Debt Securities [Member]
Securities held-to-maturity, amortized costs			122,039
Securities held-to-maturity, gross unrealized gains			2,929
Securities held-to-maturity, gross unrealized losses			173
Securities held to maturity, fair value			124,795
Collateralized Mortgage Backed Securities [Member]
Securities held-to-maturity, amortized costs			209
Securities held-to-maturity, gross unrealized gains			21
Securities held-to-maturity, gross unrealized losses
Securities held to maturity, fair value			230
Corporate Debt Securities [Member]
Securities held-to-maturity, amortized costs			982
Securities held-to-maturity, gross unrealized gains			5
Securities held-to-maturity, gross unrealized losses
Securities held to maturity, fair value			$ 987