Note 18 - Preferred Stock, Common Stock and Convertible Unit Transactions (Details Textual) $ / shares in Units, $ in Thousands			12 Months Ended
		Sep. 30, 2023 USD ($) $ / shares	Dec. 31, 2023 USD ($) $ / shares shares	Dec. 31, 2022 USD ($) $ / shares shares	Dec. 31, 2021 $ / shares shares	Jan. 31, 2024 shares	Feb. 28, 2020 USD ($)	Sep. 30, 2019 $ / shares
Preferred Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares			$ 1	$ 1
Common Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares			$ 0.01	$ 0.01
Stock Repurchased During Period, Shares (in shares)			761,149	567,450	1,084,953
Equity, Attributable to Noncontrolling Interest | $			$ 127,993	$ 131,401
Common Stock, Dividends, Per Share, Declared (in dollars per share) | $ / shares	[1]		$ 1.02	$ 0.84	$ 0.68
Special Cash Dividend [Member]
Common Stock, Dividends, Per Share, Declared (in dollars per share) | $ / shares			$ 0.09
ATM Program [Member]
Common Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares		$ 0.01						$ 0.01
Maximum Aggregate Sales Price | $		$ 500,000
Stock Issued During Period, Shares, New Issues (in shares)			0
Common Stock Available for Issuance, Value | $			$ 500,000
Class L Cumulative Redeemable Preferred Stock Depositary Shares[Member]
Stock Repurchased During Period, Shares (in shares)			43,777
Class M Cumulative Redeemable Preferred Stock Depositary Shares [Member]
Stock Repurchased During Period, Shares (in shares)			23,791
Series I, J, K, L or M Preferred Stock [Member]
Number of Votes			1,000
Number of Proxies			1,000
Number of Votes, Depositary			1
Series L Preferred Stock [Member]
Preferred Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares			$ 1	1
Preferred Stock, Liquidation Preference Per Share (in dollars per share) | $ / shares			25,000
Series M Preferred Stock [Member]
Preferred Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares			1	$ 1
Preferred Stock, Liquidation Preference Per Share (in dollars per share) | $ / shares			25,000
Depositary Share [Member]
Preferred Stock, Liquidation Preference Per Share (in dollars per share) | $ / shares			$ 25
Convertible Units [Member]
Equity, Attributable to Noncontrolling Interest | $			$ 51,200
Partners' Capital Account, Units, Converted (in shares)			2,400,000
Share Repurchase Program [Member]
Preferred Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares			$ 1
Stock Repurchase Program, Authorized Amount | $							$ 300,000
Stock Repurchased During Period, Shares (in shares)			0	0
Stock Repurchase Program, Remaining Authorized Repurchase Amount | $			$ 224,900
Share Repurchase Program [Member] | Class L Cumulative Redeemable Preferred Stock Depositary Shares[Member] | Subsequent Event [Member]
Stock Repurchase Program, Number of Shares Authorized to be Repurchased (in shares)						891,000
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)			894,000
Share Repurchase Program [Member] | Class L Cumulative Redeemable Preferred Stock Depositary Shares[Member] | Maximum [Member] | Subsequent Event [Member]
Stock Repurchase Program, Number of Shares Authorized to be Repurchased (in shares)						891,000
Share Repurchase Program [Member] | Class M Cumulative Redeemable Preferred Stock Depositary Shares [Member] | Subsequent Event [Member]
Stock Repurchase Program, Number of Shares Authorized to be Repurchased (in shares)						1,047,000
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)			1,048,000
Share Repurchase Program [Member] | Class M Cumulative Redeemable Preferred Stock Depositary Shares [Member] | Maximum [Member] | Subsequent Event [Member]
Stock Repurchase Program, Number of Shares Authorized to be Repurchased (in shares)						1,047,000
Share Repurchase Program [Member] | Cumulative Preferred Stock [Member] | Maximum [Member]
Stock Repurchase Program, Number of Shares Authorized to be Repurchased (in shares)			1,942
Share Repurchase Program [Member] | Class N Cumulative Convertible Preferred Stock Depositary Shares [Member] | Subsequent Event [Member]
Stock Repurchase Program, Number of Shares Authorized to be Repurchased (in shares)						185,000
Share Repurchase Program [Member] | Class N Cumulative Convertible Preferred Stock Depositary Shares [Member] | Maximum [Member] | Subsequent Event [Member]
Stock Repurchase Program, Number of Shares Authorized to be Repurchased (in shares)						185,000

[1] During 2023, the Company’s Board of Directors declared a $0.09 per common share special cash dividend to maintain distribution requirements as a REIT.