Note 8 - Fair Value - Carrying Amount and Estimated Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Securities	$ 20,751	$ 23,829
Securities	20,751	23,829
Fair Value, Inputs, Level 1 [Member]
Securities	0	0
Securities	0	0
Fair Value, Inputs, Level 2 [Member]
Securities	20,751	23,829
Securities	20,751	23,829
Fair Value, Inputs, Level 3 [Member]
Securities	0	0
Securities	0	0
Reported Value Measurement [Member]
Cash and cash equivalents	498,583	503,496
Securities	20,751	23,829
Loans receivable, net of allowance for loan losses	1,028,840	1,002,578
FHLB and FRB stock	7,490	7,490
Accrued interest receivable	4,695	3,941
Certificates of deposit	236,590	253,000
Borrowings	4,000	4,000
Securities	20,751	23,829
Estimate of Fair Value Measurement [Member]
Cash and cash equivalents	498,583	503,496
Securities	20,751	23,829
Loans receivable, net of allowance for loan losses	1,028,208	1,004,854
Accrued interest receivable	4,695	3,941
Certificates of deposit	237,119	253,906
Borrowings	4,000	3,998
Securities	20,751	23,829
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 1 [Member]
Cash and cash equivalents	9,567	14,115
Securities	0	0
Loans receivable, net of allowance for loan losses	0	0
FHLB and FRB stock	0	0
Accrued interest receivable	0	0
Certificates of deposit	0	0
Borrowings	0	0
Securities	0	0
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 2 [Member]
Cash and cash equivalents	489,016	489,381
Securities	20,751	23,829
Loans receivable, net of allowance for loan losses	0	0
FHLB and FRB stock	0	0
Accrued interest receivable	108	52
Certificates of deposit	237,119	253,906
Borrowings	4,000	3,998
Securities	20,751	23,829
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 3 [Member]
Cash and cash equivalents	0	0
Securities	0	0
Loans receivable, net of allowance for loan losses	1,028,208	1,004,854
FHLB and FRB stock	0	0
Accrued interest receivable	4,587	3,889
Certificates of deposit	0	0
Borrowings	0	0
Securities	$ 0	$ 0

The fair value disclosure of certificates of deposit liabilities.

No definition available.

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- Definition

The fair value portion of FHLB and FRB stock.

+ References

No definition available.

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- Definition

Fair value portion of amount due from customers or clients for goods or services, including trade receivables, that have been delivered or sold in the normal course of business, and amounts due from others, including related parties.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=121572278&loc=d3e13433-108611

+ Details

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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 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(6))
-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=121558606&loc=SL82898722-210454

Reference 3: 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=121553693&loc=d3e26610-111562

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (aa)
-URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27161-111563

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- Definition

Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

+ References

No definition available.

+ Details

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Balance Type:	debit
Period Type:	instant

- Definition

Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-URI http://asc.fasb.org/subtopic&trid=2196772

+ Details

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- Definition

This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents the amount of short-term debt existing as of the balance sheet date.

+ References

No definition available.

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