Note 3 - Mergers and Acquisitions - Pro Forma Information (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Interest Income	$ 103,467	$ 76,195	$ 51,601
Interest Expense	23,269	13,966	7,229
Net Interest Income	80,198	62,229	44,372
Provision for Loan Losses	2,606	2,390	4,237
Net Interest Income after Provision for Loan Losses	77,592	59,839	40,135
Noninterest Income	10,708	7,779	5,618
Noninterest Expense	58,448	50,248	36,802
Income Before Income Taxes	29,852	17,370	8,951
Provision for Income Taxes	6,080	3,279	4,103
Net Income	$ 23,772	$ 14,091	$ 4,848
Basic (in dollars per share)	$ 1.79	$ 1.27	$ 0.63
Diluted (in dollars per share)	$ 1.74	$ 1.22	$ 0.61
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