Note 18 - Employee Benefit Plans (Details Textual) - USD ($)	7 Months Ended	12 Months Ended			255 Months Ended
	Dec. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	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		17,559	16,458	19,377
Stock Issued During Period, Value, Employee Stock Ownership Plan		$ 706,000	$ 646,000	$ 600,000
Employee Stock Ownership Plan (ESOP), Shares Contributed to ESOP		58,988	57,014	103,367
Employee Stock Ownership Plan (ESOP), Shares in ESOP, Total	794,759	794,759
Percentage of Outstanding Common Stock under Employee Stock Ownership Plan	1.00%	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		$ 3,100,000	$ 2,300,000	$ 2,100,000
Percentage of Participant Borrowing Capacity of Vested Amount		50.00%
Cash Surrender Value of Life Insurance	$ 49,900,000	$ 49,900,000
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