Partners' Capital of the Operating Partnership - Narrative (Details) - USD ($) $ in Thousands			1 Months Ended	12 Months Ended
	Aug. 15, 2017	Mar. 30, 2017	Jul. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Class of Stock [Line Items]
Common stock, shares issued (in shares)				106,016,287	100,746,988
Aggregate net proceeds after selling commissions				$ 353,722	$ 130,693	$ 326,058
Original issuance costs of redeemed preferred stock and preferred units (Note 13)				$ 0	$ 0	(7,589)
Series H Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock (in shares)	4,000,000	4,000,000
Preferred stock, dividend rate	6.375%
Series G Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock (in shares)		4,000,000
Preferred stock, dividend rate		6.875%
Series G And H Preferred Stock [Member]
Class of Stock [Line Items]
Original issuance costs of redeemed preferred stock and preferred units (Note 13)						$ (7,600)
Forward Equity Sale [Member]
Class of Stock [Line Items]
Aggregate net proceeds after selling commissions			$ 354,300
Forward Equity Sale [Member] | Common Stock [Member]
Class of Stock [Line Items]
Common stock, shares issued (in shares)			5,000,000
Aggregate net proceeds after selling commissions			$ 354,300
Common units (in units)			5,000,000