Note 3 - Earnings Per Common Share - Computation of Earnings Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2024	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Net income available to common stockholders	$ 18,862	$ 15,652	$ 17,547	$ 15,696	$ 17,764	$ 19,898	$ 19,885	$ 23,420	$ 67,757	$ 80,967	$ 119,174
Earnings allocated to participating securities									(187)	(216)	(287)
Income attributable to common stock									$ 67,570	$ 80,751	$ 118,887
Weighted average common shares outstanding, including participating securities (in shares)									38,376	38,913	39,355
Weighted average participating securities (in shares)									(106)	(104)	(95)
Weighted average common shares outstanding (in shares)									38,270	38,809	39,260
Incremental shares from assumed conversions of options, deferred stock units, performance units and restricted stock (in shares)									211	153	216
Weighted average common and equivalent shares outstanding (in shares)									38,481	38,962	39,476
Earnings per common share:
Basic (in dollars per share)	$ 0.49	$ 0.41	$ 0.46	$ 0.41	$ 0.46	$ 0.51	$ 0.51	$ 0.6	$ 1.77	$ 2.08	$ 3.03
Diluted (in dollars per share)	$ 0.49	$ 0.41	$ 0.46	$ 0.41	$ 0.46	$ 0.51	$ 0.51	$ 0.59	$ 1.76	$ 2.07	$ 3.01