Note 16 - Stockholders' Equity (Details Textual) - USD ($) $ / shares in Units, $ in Millions	9 Months Ended
	Sep. 30, 2022	Dec. 31, 2021	Aug. 31, 2021	Feb. 28, 2020
Preferred Stock, Par or Stated Value Per Share (in dollars per share)	$ 1.00	$ 1.00
Common Stock, Par or Stated Value Per Share (in dollars per share)	$ 0.01	$ 0.01
ATM Program [Member]
Common Stock, Par or Stated Value Per Share (in dollars per share)			$ 0.01
Sales of Stock Maximum Sales Price			$ 500.0
Stock Issued During Period, Shares, New Issues (in shares)	450,000
Proceeds from Issuance of Common Stock	$ 11.3
Common Stock Available for Issuance, Value	$ 411.0
Class L Cumulative Redeemable Preferred Stock Depositary Shares[Member]
Stock Repurchased During Period, Shares (in shares)	54,508
Class M Cumulative Redeemable Preferred Stock Depositary Shares [Member]
Stock Repurchased During Period, Shares (in shares)	90,760
Share Repurchase Program [Member]
Preferred Stock, Par or Stated Value Per Share (in dollars per share)	$ 1.00
Common Stock, Par or Stated Value Per Share (in dollars per share)				$ 0.01
Stock Repurchase Program, Authorized Amount				$ 300.0
Stock Repurchased During Period, Shares (in shares)	0
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 224.9
Share Repurchase Program [Member] | Maximum [Member]
Stock Repurchase Program, Number of Shares Authorized to be Repurchased (in shares)	1,958
Share Repurchase Program [Member] | Class L Cumulative Redeemable Preferred Stock Depositary Shares[Member] | Maximum [Member]
Stock Repurchase Program, Number of Shares Authorized to be Repurchased (in shares)	900,000
Share Repurchase Program [Member] | Class M Cumulative Redeemable Preferred Stock Depositary Shares [Member] | Maximum [Member]
Stock Repurchase Program, Number of Shares Authorized to be Repurchased (in shares)	1,058,000