Preferred Stock - Narrative (Details) - USD ($) $ in Thousands		9 Months Ended
	May 28, 2020	Sep. 30, 2020	Dec. 31, 2019
Class of Stock [Line Items]
Preferred stock, shares authorized (in shares)		5,000,000	5,000,000
Liquidation Amount		$ 487,500
LIBOR | Beginning on or after August 1, 2025
Class of Stock [Line Items]
Basis spread on variable rate		4.262%
LIBOR | Beginning on or after May 1, 2026
Class of Stock [Line Items]
Basis spread on variable rate		4.92%
LIBOR | Beginning on or after May 1, 2024
Class of Stock [Line Items]
Basis spread on variable rate		3.859%
Series A Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares authorized (in shares)		1,000
Preferred Stock, Shares Outstanding		1,000
Liquidation Amount		$ 100,000
Annual Dividend Rate		6.20%
Series B Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares authorized (in shares)		8,625
Preferred Stock, Shares Outstanding		8,000
Liquidation Amount		$ 80,000
Annual Dividend Rate		6.625%
Series C Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares authorized (in shares)		5,750
Preferred Stock, Shares Outstanding		5,750
Liquidation Amount		$ 57,500
Annual Dividend Rate		6.60%
Series D Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares authorized (in shares)		10,000
Preferred Stock, Shares Outstanding		10,000
Liquidation Amount		$ 100,000
Annual Dividend Rate		6.10%
Series E Preferred Stock
Class of Stock [Line Items]
Sale of preferred stock, net	$ 145,000
Preferred stock, shares authorized (in shares)		1,725
Preferred Stock, Shares Outstanding		1,500
Liquidation Amount		$ 150,000
Annual Dividend Rate		6.50%