Note 1 - Description of Business and Basis of Presentation (Restated) - Summary of Effects of the Restatement (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Jul. 01, 2021	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020	Dec. 31, 2019
Income tax expense	$ 1,780	$ 2,140	$ 3,690	$ 7,090
Net income	8,196	9,944	25,051	28,485
Comprehensive income	$ 7,899	$ 10,088	$ 31,464	$ 27,949
Net income per basic share (in dollars per share)	$ 0.53	$ 0.66	$ 1.63	$ 1.89
Net income per diluted share (in dollars per share)	$ 0.51	$ 0.63	$ 1.56	$ 1.85
Deferred tax asset	$ 352		$ 352				$ 0
Total assets	422,529	$ 367,238	422,529	$ 367,238			393,924
Deferred tax liability	0		0				450
Retained earnings	161,511		161,511				141,972
Total shareholders’ equity	222,735	183,581	222,735	183,581	$ 215,315	$ 215,315	191,630	$ 174,475	$ 157,554
Total liabilities and shareholders’ equity	422,529		422,529				393,924
Deferred income tax benefit			(2,927)	(3,654)
Retained Earnings [Member]
Net income	8,196	9,944	25,051	28,485
Total shareholders’ equity	161,511	$ 130,968	161,511	$ 130,968	155,212	$ 155,212	$ 141,972	$ 124,243	$ 107,581
Previously Reported [Member]
Income tax expense			5,490
Net income			23,251
Comprehensive income			$ 29,664
Net income per basic share (in dollars per share)			$ 1.51
Net income per diluted share (in dollars per share)			$ 1.45
Deferred tax asset	0		$ 0
Total assets	422,177		422,177
Deferred tax liability	1,448		1,448
Retained earnings	159,711		159,711
Total shareholders’ equity	220,935		220,935		213,515
Total liabilities and shareholders’ equity	422,177		422,177
Deferred income tax benefit			(1,127)
Previously Reported [Member] | Retained Earnings [Member]
Net income			23,251
Total shareholders’ equity	159,711		159,711		153,412
Revision of Prior Period, Error Correction, Adjustment [Member]
Income tax expense			(1,800)
Net income			1,800
Comprehensive income			$ 1,800
Net income per basic share (in dollars per share)			$ 0.12
Net income per diluted share (in dollars per share)			$ 0.11
Deferred tax asset	352		$ 352
Total assets	352		352
Deferred tax liability	(1,448)		(1,448)
Retained earnings	1,800		1,800
Total shareholders’ equity	1,800		1,800		1,800
Total liabilities and shareholders’ equity	352		352
Deferred income tax benefit			(1,800)
Revision of Prior Period, Error Correction, Adjustment [Member] | Retained Earnings [Member]
Net income			1,800
Total shareholders’ equity	$ 1,800		$ 1,800		$ 1,800