Note 18 - Earnings Per Share - Computation of Earnings Per Share (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Net income attributable to common shares	$ 11,639,000	$ 15,051,000	$ 18,091,000	$ 14,240,000	$ 14,082,000	$ 10,686,000	$ 8,697,000	$ 10,673,000	$ 59,021,000	$ 44,138,000	$ 49,456,000
Weighted average common shares outstanding (in shares)									15,986,857	16,268,689	16,405,159
Basic earnings per common share (in dollars per share)	$ 0.74	$ 0.95	$ 1.12	$ 0.87	$ 0.86	$ 0.66	$ 0.54	$ 0.65	$ 3.69	$ 2.71	$ 3.01
Net income	$ 11,639,000	$ 15,051,000	$ 18,091,000	$ 14,240,000	$ 14,082,000	$ 10,686,000	$ 8,697,000	$ 10,673,000	$ 59,021,000	$ 44,138,000	$ 49,456,000
Weighted average common shares outstanding for basic earnings per common share (in shares)									15,986,857	16,268,689	16,405,159
Add: Dilutive effects of share-based awards (in shares)									446	630	3,976
Average shares and dilutive potential common shares (in shares)									15,987,303	16,269,319	16,409,135
Diluted earnings per common share (in dollars per share)	$ 0.74	$ 0.95	$ 1.12	$ 0.87	$ 0.86	$ 0.66	$ 0.54	$ 0.65	$ 3.69	$ 2.71	$ 3.01