Equity (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands				3 Months Ended			9 Months Ended		52 Months Ended
		Feb. 22, 2022	Jul. 31, 2021	Sep. 30, 2022	Jun. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Dec. 31, 2021	Jun. 13, 2018
Subsidiary, Sale of Stock [Line Items]
Preferred Stock, Shares Issued				9,420,421			9,420,421		9,420,421	9,400,000
Proceeds from Issuance of Preferred Stock and Preference Stock	[1]						$ 511	$ 0
Preferred Stock, Shares Authorized				100,000,000			100,000,000		100,000,000	100,000,000
Preferred Stock, Par or Stated Value Per Share				$ 0.001			$ 0.001		$ 0.001	$ 0.001
Common stock, shares authorized (in shares)				100,000,000			100,000,000		100,000,000	100,000,000
Common Stock, Par or Stated Value Per Share				$ 0.001			$ 0.001		$ 0.001	$ 0.001
Dividends declared (in usd per share)				$ 0.45		$ 0.45	$ 1.35	$ 1.19
Dividends paid							$ (91,459)	$ (58,469)
Common shares issued and outstanding upon conversion of all convertible securities (in shares)				61,221,944			61,221,944		61,221,944	58,180,342
Number of shares authorized to be repurchased (in shares)											1,550,000
Shares repurchased (in shares)				(40,000)		0	(128,184)	0	(830,149)
Average price per share (USD per share)				$ 12.38			$ 12.94		$ 13.29
Total cost				$ (495)	$ (1,164)		$ (1,700)		$ (11,000)
Shares Issued As Payment of Incentive Fee, Shares		19,094	37,373	0		37,373	19,094	37,373
Preferred Stock, Shares Outstanding				9,420,421			9,420,421		9,420,421	9,400,000
Stock Issued During Period, Shares, New Issues				516,942		7,852,900	3,085,642	7,852,900
Common ATM Program
Subsidiary, Sale of Stock [Line Items]
Maximum shares available to be issued under at the market program							10,000,000
Commissions and offering costs				$ 100		$ 400	$ 800	$ 400
Stock Issued During Period, Shares, New Issues				516,942		1,549,900	3,085,642	1,549,900
Proceeds from issuance of shares, net				$ 8,000		$ 28,200	$ 53,200	$ 28,200
Series A Preferred Stock
Subsidiary, Sale of Stock [Line Items]
Preferred Stock, Dividend Rate, Percentage							6.75%
Preferred Stock, Par or Stated Value Per Share				$ 0.001			$ 0.001		$ 0.001
Preferred Stock, Liquidation Preference Per Share				$ 25.00			$ 25.00		$ 25.00
Preferred Stock Dividend Rate Variable Rate Spread							5.196%
Preferred Stock, Amount of Preferred Dividends in Arrears							$ 2,500	$ 1,600
Preferred Stock, Shares Outstanding				4,600,000			4,600,000		4,600,000	4,600,000
Series B Preferred Stock
Subsidiary, Sale of Stock [Line Items]
Preferred Stock, Dividend Rate, Percentage							6.25%
Preferred Stock, Par or Stated Value Per Share				$ 0.001			$ 0.001		$ 0.001
Preferred Stock, Liquidation Preference Per Share				$ 25.00			$ 25.00		$ 25.00
Preferred Stock Dividend Rate Variable Rate Spread							4.99%
Preferred Stock, Shares Outstanding				4,820,421			4,820,421		4,820,421	4,800,000
Operating Partnership Units [Member]
Subsidiary, Sale of Stock [Line Items]
Stock issued during period, shares, conversion of units				4,066		5,710	4,066	5,710

[1] Net of discounts and commissions.