Note 3 - Mergers and Acquisitions - (Details Textual) - USD ($)			3 Months Ended	12 Months Ended
	Mar. 01, 2022	Apr. 01, 2021	Mar. 31, 2022	Dec. 31, 2021	Feb. 28, 2022	Mar. 31, 2021
Assets, Total			$ 5,362,235,000	$ 4,726,378,000
Loans and Leases Receivable, Net of Deferred Income			3,748,498,000	3,189,608,000
Deposits, Total			4,657,738,000	4,077,283,000
Liabilities, Total			4,905,398,000	4,293,010,000
Goodwill, Ending Balance			89,911,000	$ 59,894,000
Core Deposits [Member]
Finite-Lived Intangible Asset, Useful Life (Year)				10 years
Texas Citizens Bancorp [Member]
Assets, Total					$ 534,200,000
Loans and Leases Receivable, Net of Deferred Income					349,500,000
Deposits, Total					$ 477,200,000
Smith Shellnut Wilson, LLC [Member]
Assets, Total						$ 3,600,000
Liabilities, Total						$ 2,300,000
Texas Citizens Bancorp [Member]
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares (in shares)	2,069,532
Business Combination, Acquisition Related Costs			$ 811,000	$ 515,000
Goodwill, Ending Balance	$ 30,017,000
Acquisition of SSW [Member]
Payments to Acquire Businesses, Gross		$ 7,300,000
Business Combination, Consideration Transferred, Liabilities Incurred		3,900,000
Goodwill, Ending Balance		$ 6,500,000
Acquisition of SSW [Member] | Customer-Related Intangible Assets [Member]
Finite-Lived Intangible Asset, Useful Life (Year)		10 years
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles		$ 4,300,000