Note 17 - Stockholders' Equity - Dividends Declared (Details) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Common Shares (in dollars per share)	$ 0.17000	$ 0.10000	$ 0.51000	$ 0.38000
Series L Preferred Stock [Member]
Preferred Shares (in dollars per share)	0.32031	0.32031	0.96093	0.96093
Series M Preferred Stock [Member]
Preferred Shares (in dollars per share)	$ 0.32813	$ 0.32813	$ 0.98439	$ 0.98439