Note 3 - Mergers and Acquisitions - Pro Forma Information (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Interest Income	$ 76,195	$ 51,601	$ 43,418
Interest Expense	13,966	7,229	5,826
Net Interest Income	62,229	44,372	37,592
Provision for Loan Losses	2,390	4,237	1,220
Net Interest Income after Provision for Loan Losses	59,839	40,135	36,372
Noninterest Income	7,779	5,618	5,421
Noninterest Expense	50,248	36,802	35,069
Income Before Income Taxes	17,370	8,951	6,724
Provision for Income Taxes	3,279	4,103	1,613
Net Income	$ 14,091	$ 4,848	$ 5,111
Basic (in dollars per share)	$ 1.27	$ 0.63	$ 0.73
Diluted (in dollars per share)	$ 1.22	$ 0.61	$ 0.70
Pro Forma [Member] | Minden Bancorp and Richland State Bancorp [Member]
Interest Income	$ 88,277	$ 79,230
Interest Expense	15,132	9,308
Net Interest Income	73,145	69,922
Provision for Loan Losses	2,590	4,237
Net Interest Income after Provision for Loan Losses	70,555	65,685
Noninterest Income	11,496	8,705
Noninterest Expense	58,520	52,184
Income Before Income Taxes	23,531	22,206
Provision for Income Taxes	4,506	8,676
Net Income	$ 19,025	$ 13,530
Basic (in dollars per share)	$ 1.50	$ 1.03
Diluted (in dollars per share)	$ 1.45	$ 1.01