Equity and Accumulated Other Comprehensive Income (Loss), Net - Redeemable Preferred Stock (Details) $ / shares in Units, $ in Thousands								12 Months Ended
	Oct. 10, 2019 $ / shares shares	Mar. 13, 2019 $ / shares shares	Sep. 14, 2017 $ / shares shares	Sep. 07, 2017	Aug. 07, 2017 $ / shares shares	Aug. 24, 2015 $ / shares shares	Apr. 09, 2013 $ / shares shares	Dec. 31, 2020 USD ($) item $ / shares shares	Dec. 31, 2019 USD ($) $ / shares shares	Oct. 15, 2020 $ / shares	Sep. 08, 2020 $ / shares	Apr. 01, 2019 $ / shares
Class of Stock
Liquidation preference | $								$ 956,250	$ 1,456,250
Preferred stock, issued (shares) | shares								38,250,000	58,250,000
Net proceeds from preferred stock | $								$ 950,940	$ 1,434,420
Number of quarters with no dividends triggering voting rights | item								6
Preferred stock, liquidation preference per share (in dollars per share)								$ 25.00	$ 25.00
Preferred Stock, Redemption Price Per Share								$ 25.00
Series C Cumulative Redeemable Perpetual Preferred Stock
Class of Stock
Share cap (in shares) | shares			0.6389035
Liquidation preference | $								$ 201,250
Preferred stock dividend per share amount (in dollars per share)			$ 1.65625					$ 1.65625
Preferred stock, issued (shares) | shares								8,050,000	8,050,000
Net proceeds from preferred stock | $								$ 219,250	$ 219,250
Dividend rate percentage			6.625%
Series G Cumulative Redeemable Preferred Stock
Class of Stock
Share cap (in shares) | shares							0.7532000
Preferred stock dividend per share amount (in dollars per share)							$ 1.46875	$ 1.46875
Preferred stock, issued (shares) | shares									10,000,000
Net proceeds from preferred stock | $									$ 241,468
Preferred stock, liquidation preference per share (in dollars per share)										$ 25.057118
Dividend rate percentage							5.875%
Preferred Stock, Redemption Price Per Share										25.00
Series H Cumulative Redeemable Preferred Stock
Class of Stock
Preferred stock dividend per share amount (in dollars per share)								1.84375
Preferred Stock, Redemption Price Per Share												$ 25.00
Series I Cumulative Redeemable Preferred Stock
Class of Stock
Share cap (in shares) | shares						0.7623100
Preferred stock dividend per share amount (in dollars per share)						$ 1.58750		$ 1.58750
Preferred stock, issued (shares) | shares									10,000,000
Net proceeds from preferred stock | $									$ 242,012
Preferred stock, liquidation preference per share (in dollars per share)											$ 25.29545
Dividend rate percentage						6.35%
Preferred Stock, Redemption Price Per Share											25.00
Series J Cumulative Redeemable Preferred Stock
Class of Stock
Share cap (in shares) | shares					0.4252100
Liquidation preference | $								$ 200,000
Preferred stock dividend per share amount (in dollars per share)					$ 1.31250			$ 1.31250
Preferred stock, issued (shares) | shares								8,000,000	8,000,000
Net proceeds from preferred stock | $								$ 193,540	$ 193,540
Dividend rate percentage					5.25%
Series K Cumulative Redeemable Preferred Stock
Class of Stock
Share cap (in shares) | shares		0.4361100
Liquidation preference | $								$ 210,000
Preferred stock dividend per share amount (in dollars per share)								$ 1.46250
Preferred stock, issued (shares) | shares								8,400,000	8,400,000
Net proceeds from preferred stock | $								$ 203,264	$ 203,264
Dividend rate percentage		5.85%
Series L Cumulative Redeemable Preferred Units
Class of Stock
Share cap (in shares) | shares	0.3851800
Liquidation preference | $								$ 345,000
Preferred stock dividend per share amount (in dollars per share)								$ 1.30000
Preferred stock, issued (shares) | shares								13,800,000	13,800,000
Net proceeds from preferred stock | $								$ 334,886	$ 334,886
Dividend rate percentage	5.20%
Series C Preferred Units
Class of Stock
Liquidation preference | $								$ 201,250
Preferred stock dividend per share amount (in dollars per share)			$ 1.65625
Preferred stock, issued (shares) | shares								8,050,000	8,050,000
Net proceeds from preferred stock | $								$ 219,250	$ 219,250
Dividend rate percentage			6.625%
Series G Preferred Units
Class of Stock
Preferred stock dividend per share amount (in dollars per share)							$ 1.46875
Preferred stock, issued (shares) | shares									10,000,000
Net proceeds from preferred stock | $									$ 241,468
Preferred stock, liquidation preference per share (in dollars per share)										25.00
Dividend rate percentage							5.875%
Preferred Stock, Redemption Price Per Share										$ 25.057118
Series I Preferred Units
Class of Stock
Preferred stock dividend per share amount (in dollars per share)						$ 1.58750
Preferred stock, issued (shares) | shares									10,000,000
Net proceeds from preferred stock | $									$ 242,012
Preferred stock, liquidation preference per share (in dollars per share)											25.00
Dividend rate percentage					6.35%
Preferred Stock, Redemption Price Per Share											$ 25.29545
Series J Preferred Units
Class of Stock
Liquidation preference | $								$ 200,000
Preferred stock dividend per share amount (in dollars per share)					$ 1.31250
Preferred stock, issued (shares) | shares								8,000,000	8,000,000
Net proceeds from preferred stock | $								$ 193,540	$ 193,540
Dividend rate percentage				5.25%
Series K Preferred Units
Class of Stock
Liquidation preference | $								$ 210,000
Preferred stock dividend per share amount (in dollars per share)		$ 1.46250
Preferred stock, issued (shares) | shares								8,400,000	8,400,000
Net proceeds from preferred stock | $								$ 203,264	$ 203,264
Dividend rate percentage		5.85%
Series L Preferred Units
Class of Stock
Liquidation preference | $								$ 345,000
Preferred stock dividend per share amount (in dollars per share)	$ 1.30000
Preferred stock, issued (shares) | shares								13,800,000	13,800,000
Net proceeds from preferred stock | $								$ 334,886	$ 334,886
Dividend rate percentage	5.20%