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		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020	Dec. 31, 2019
Income tax expense (benefit)	$ (840)	$ 3,700	$ 1,910	$ 4,950
Net income	6,377	15,174	16,855	18,541
Comprehensive income	$ 13,025	$ 15,390	$ 23,565	$ 17,861
Net income per basic share (in dollars per share)	$ 0.41	$ 1.01	$ 1.10	$ 1.23
Net income per diluted share (in dollars per share)	$ 0.40	$ 1.00	$ 1.05	$ 1.22
Deferred tax asset	$ 447		$ 447			$ 0
Total assets	429,193	$ 358,170	429,193	$ 358,170		393,924
Deferred tax liability	0		0			450
Retained earnings	155,212		155,212			141,972
Total shareholders’ equity	215,315	174,475	215,315	174,475	$ 201,383	191,630	$ 158,390	$ 157,554
Total liabilities and shareholders’ equity	429,193		429,193			393,924
Deferred income tax benefit			(2,926)	(2,417)
Retained Earnings [Member]
Net income	6,377	15,174	16,855	18,541
Total shareholders’ equity	155,212	$ 124,243	155,212	$ 124,243	$ 150,734	$ 141,972	$ 109,086	$ 107,581
Previously Reported [Member]
Income tax expense (benefit)	960		3,710
Net income	4,577		15,055
Comprehensive income	$ 11,225		$ 21,765
Net income per basic share (in dollars per share)	$ 0.30		$ 0.98
Net income per diluted share (in dollars per share)	$ 0.28		$ 0.94
Deferred tax asset	$ 0		$ 0
Total assets	428,746		428,746
Deferred tax liability	1,353		1,353
Retained earnings	153,412		153,412
Total shareholders’ equity	213,515		213,515
Total liabilities and shareholders’ equity	428,746		428,746
Deferred income tax benefit			(1,126)
Previously Reported [Member] | Retained Earnings [Member]
Net income	4,577		15,055
Total shareholders’ equity	153,412		153,412
Revision of Prior Period, Error Correction, Adjustment [Member]
Income tax expense (benefit)	(1,800)		(1,800)
Net income	1,800		1,800
Comprehensive income	$ 1,800		$ 1,800
Net income per basic share (in dollars per share)	$ 0.11		$ 0.12
Net income per diluted share (in dollars per share)	$ 0.12		$ 0.11
Deferred tax asset	$ 447		$ 447
Total assets	447		447
Deferred tax liability	(1,353)		(1,353)
Retained earnings	1,800		1,800
Total shareholders’ equity	1,800		1,800
Total liabilities and shareholders’ equity	447		447
Deferred income tax benefit			(1,800)
Revision of Prior Period, Error Correction, Adjustment [Member] | Retained Earnings [Member]
Net income	1,800		1,800
Total shareholders’ equity	$ 1,800		$ 1,800