Equity (Narrative) (Details) - USD ($)		3 Months Ended		12 Months Ended
		Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023	Dec. 31, 2024	Mar. 21, 2023	Dec. 31, 2022	Jun. 13, 2018
Subsidiary, Sale of Stock [Line Items]
Preferred Stock, Shares Authorized		100,000,000		100,000,000
Preferred Stock, Par or Stated Value Per Share		$ 0.001		$ 0.001
Preferred Stock, Shares Outstanding		14,757,222		14,757,222
Proceeds from Issuance of Preferred Stock and Preference Stock	[1]	$ 0	$ 96,850,000
Common stock, shares authorized (in shares)		200,000,000		200,000,000
Common Stock, Par or Stated Value Per Share		$ 0.001		$ 0.001
Common stock, shares outstanding		85,056,648	67,185,076	83,000,488			63,812,215
Stock Issued During Period, Shares, New Issues		2,103,725	4,433,861
Common shares issued and outstanding upon conversion of all convertible securities (in shares)		85,891,703		83,795,803
Number of shares authorized to be repurchased (in shares)								1,550,000
Stock Repurchase Program, Authorized Amount		$ 45,300,000				$ 50,000,000
Shares repurchased		(47,565)	(1,061,000)
Average price per share (USD per share)		$ 11.01	$ 11.38
Total cost		$ (524,000)	$ (12,072,000)
Preferred ATM Program
Subsidiary, Sale of Stock [Line Items]
Maximum shares available to be issued under at the market program		100,000,000
At The Market Program, Remaining Authorized Amount			99,500,000
2021 Common ATM Program
Subsidiary, Sale of Stock [Line Items]
Maximum shares available to be issued under at the market program		10,000,000
2023 Common ATM Program
Subsidiary, Sale of Stock [Line Items]
Proceeds from issuance of shares, net		$ 26,900,000
Maximum shares available to be issued under at the market program		225,000,000
Stock Issued During Period, Shares, New Issues		2,103,725
Commissions and offering costs		$ 300,000
Common ATM Programs
Subsidiary, Sale of Stock [Line Items]
Proceeds from issuance of shares, net			$ 60,500,000
Stock Issued During Period, Shares, New Issues			4,433,861
Commissions and offering costs			$ 900,000
Series C Preferred Stock
Subsidiary, Sale of Stock [Line Items]
Proceeds from issuance of shares, net			96,500,000
Commissions and offering costs			$ 3,500,000
Series A Preferred Stock
Subsidiary, Sale of Stock [Line Items]
Preferred Stock, Par or Stated Value Per Share		$ 0.001
Preferred Stock, Amount of Preferred Dividends in Arrears		$ 4,000,000		$ 4,000,000.0
Preferred Stock, Shares Outstanding		4,600,000		4,600,000
Preferred Stock, Dividend Rate, Percentage		6.75%
Preferred Stock, Liquidation Preference Per Share		$ 25.00
Preferred Stock Dividend Rate Variable Rate Spread		5.196%
Series B Preferred Stock
Subsidiary, Sale of Stock [Line Items]
Preferred Stock, Par or Stated Value Per Share		$ 0.001
Preferred Stock, Shares Outstanding		4,820,421		4,820,421
Preferred Stock, Dividend Rate, Percentage		6.25%
Preferred Stock, Liquidation Preference Per Share		$ 25.00
Preferred Stock Dividend Rate Variable Rate Spread		4.99%
Series C Preferred Stock
Subsidiary, Sale of Stock [Line Items]
Preferred Stock, Par or Stated Value Per Share					$ 0.001
Preferred Stock, Shares Outstanding		4,000,000
Preferred Stock, Dividend Rate, Percentage		8.625%
Preferred Stock, Liquidation Preference Per Share		$ 25.00
Preferred Stock Dividend Rate Variable Rate Spread		5.13%
Series D Preferred Stock
Subsidiary, Sale of Stock [Line Items]
Preferred Stock, Par or Stated Value Per Share		$ 0.01
Preferred Stock, Shares Outstanding		379,668
Preferred Stock, Dividend Rate, Percentage		7.00%
Preferred Stock, Liquidation Preference Per Share		$ 25.00
Series E Preferred Stock
Subsidiary, Sale of Stock [Line Items]
Preferred Stock, Par or Stated Value Per Share		$ 0.01
Preferred Stock, Shares Outstanding		957,133
Preferred Stock, Dividend Rate, Percentage		8.25%
Preferred Stock, Liquidation Preference Per Share		$ 25.00			$ 25.00
Preferred Stock Dividend Rate Variable Rate Spread		5.664%

[1] Net of discounts and commissions.