Note 18 - Employee Benefit Plans (Details Textual) - USD ($)	7 Months Ended	12 Months Ended			255 Months Ended
	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	May 31, 2018
Minimum Number of Years Allowed to Participate in Employee Stock Ownership Plan		2 years
Stock Issued During Period, Shares, Employee Stock Ownership Plan		22,933	17,559	16,458
Stock Issued During Period, Value, Employee Stock Ownership Plan		$ 827,000	$ 706,000	$ 646,000
Employee Stock Ownership Plan (ESOP), Number of Allocated Shares	58,988	22,309	58,988	57,014
Employee Stock Ownership Plan (ESOP), Shares in ESOP, Total		783,975
Percentage of Outstanding Common Stock under Employee Stock Ownership Plan		1.00%
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent					75.00%
Defined Contribution Plan, Employers Matching Contribution, Vesting Percentage, Less Than Two Years of Service					0.00%
Defined Contribution Plan, Employers Matching Contribution, Vesting Percentage, After Two Years of Service					25.00%
Defined Contribution Plan, Employers Matching Contribution, Vesting Percentage, After Two Years of Service, Increment					25.00%
Defined Contribution Plan, Employers Matching Contribution, Vesting Percentage, After Five Years of Service					100.00%
Defined Contribution Plan, Employer Matching Contribution, Percent of Match	100.00%
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	5.00%
Defined Contribution Plan, Employer Discretionary Contribution Amount		$ 3,500,000	$ 3,100,000	$ 2,300,000
Percentage of Participant Borrowing Capacity of Vested Amount		50.00%
Cash Surrender Value of Life Insurance		$ 51,100,000
Maximum [Member]
Employee Stock Ownership Plan (ESOP), Debt Structure, Direct Loan, Employer Cash Payments Used for Debt Service		50,000
Minimum [Member]
Employee Stock Ownership Plan (ESOP), Debt Structure, Direct Loan, Employer Cash Payments Used for Debt Service		$ 1,000