Equity - Preferred Stock Outstanding and Dividends (Details) - $ / shares	3 Months Ended			9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2020	Dec. 31, 2019
Class of Stock [Line Items]
Preferred stock, outstanding (in shares)	20,400,000			20,400,000	20,400,000
Series C Cumulative Redeemable Preferred Shares
Class of Stock [Line Items]
Preferred stock, outstanding (in shares)	5,000,000			5,000,000	5,000,000
Preferred stock, dividend rate, percentage				6.50%
Dividend per share/unit (in usd per share)	$ 0.41	$ 0.41	$ 0.41
Series D Cumulative Redeemable Preferred Shares
Class of Stock [Line Items]
Preferred stock, outstanding (in shares)	5,000,000			5,000,000	5,000,000
Preferred stock, dividend rate, percentage				6.375%
Dividend per share/unit (in usd per share)	$ 0.40	0.40	0.40
Series E Cumulative Redeemable Preferred Shares
Class of Stock [Line Items]
Preferred stock, outstanding (in shares)	4,400,000			4,400,000	4,400,000
Preferred stock, dividend rate, percentage				6.375%
Dividend per share/unit (in usd per share)	$ 0.40	0.40	0.40
Series F Cumulative Redeemable Preferred Shares
Class of Stock [Line Items]
Preferred stock, outstanding (in shares)	6,000,000			6,000,000	6,000,000
Preferred stock, dividend rate, percentage				6.30%
Dividend per share/unit (in usd per share)	$ 0.39	$ 0.39	$ 0.39