Note 2 - Income Per Share - Calculation of Net Income Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended				6 Months Ended
		Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2022	Jun. 30, 2021
Numerators:
Income from continuing operations		$ 24,526		$ 15,436		$ 46,693	$ 24,019
(Loss) income from discontinued operations		0		(19)		0	2,540
Net income		$ 24,526	$ 22,167	$ 15,417	$ 11,140	$ 46,693	$ 26,559
Denominator:
Denominator for basic income per share – weighted-average shares (in shares)		15,514,000		16,765,000		16,058,000	16,858,000
Effect of dilutive securities:
Diluted weighted average shares outstanding (in shares)		15,761,000		17,022,000		16,321,000	17,052,000
Basic income per share:
Income from continuing operations (in dollars per share)		$ 1.58		$ 0.92		$ 2.91	$ 1.42
(Loss) income from discontinued operations (in dollars per share)		0		0		0	0.15
Net income (in dollars per share)	[1]	1.58		0.92		2.91	1.58
Diluted income per share:
Income from continuing operations (in dollars per share)		1.56		0.91		2.86	1.41
(Loss) income from discontinued operations (in dollars per share)		0		0		0	0.15
Net income (in dollars per share)	[1]	$ 1.56		$ 0.91		$ 2.86	$ 1.56
Restricted Stock [Member]
Effect of dilutive securities:
Equivalent shares issuable upon conversion of unvested shares (in shares)		237,000		257,000		252,000	194,000
Incremental Common Shares Attributable to Dilutive Effect of Share-Based Payment Arrangements (in shares)		237,000		257,000		252,000	194,000
Share-Based Payment Arrangement, Option [Member]
Effect of dilutive securities:
Incremental Common Shares Attributable to Dilutive Effect of Share-Based Payment Arrangements (in shares)		10,000		0		11,000	0

[1] Sum of the individual amounts may not add due to rounding.