Note 3 - Loans and Allowance for Credit Losses - Retail Credit Exposure (Details) - USD ($)		Mar. 31, 2022	Dec. 31, 2021
Loans		$ 3,555,790,000	$ 3,453,459,000
Retail Portfolio Segment [Member]
Loans		551,228,000	503,035,000
Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member]
Loans		522,556,000	442,547,000
Retail Portfolio Segment [Member] | Other Consumer Loans [Member]
Loans	[1]	28,672,000	60,488,000
Retail Portfolio Segment [Member] | Performing Financial Instruments [Member] | One to Four Family Mortgages [Member]
Loans		520,946,000	440,861,000
Retail Portfolio Segment [Member] | Performing Financial Instruments [Member] | Other Consumer Loans [Member]
Loans		28,670,000	60,369,000
Retail Portfolio Segment [Member] | Nonperforming Financial Instruments [Member] | One to Four Family Mortgages [Member]
Loans		1,610,000	1,686,000
Retail Portfolio Segment [Member] | Nonperforming Financial Instruments [Member] | Other Consumer Loans [Member]
Loans		$ 2,000	$ 119,000

[1] In conjunction with the adoption of the CECL methodology effective January 1, 2022, home equity lines of credit were reclassified to 1-4 family mortgage loans from other consumer loans. Home equity lines of credit totaled $31.9 million and $29.5 million as of March 31, 2022 and December 31, 2021, respectively.