Shareholders' Equity / Partners' Capital - Distributions (Details) - $ / shares	3 Months Ended				6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019
Class A common shares/units
Class of Stock [Line Items]
Common stock dividend declared (in dollars per share)	$ 0.05	$ 0.05	$ 0.05	$ 0.05
Class B common shares
Class of Stock [Line Items]
Common stock dividend declared (in dollars per share)	0.05	0.05	0.05	0.05
Series C Preferred Stock
Class of Stock [Line Items]
Preferred shares, dividends declared (in dollars per share)	0	0	0	0.34
Preferred stock, dividend rate, percentage					5.50%
Series D Perpetual Preferred Shares/Units
Class of Stock [Line Items]
Preferred shares, dividends declared (in dollars per share)	0.41	0.41	0.41	0.41
Preferred stock, dividend rate, percentage					6.50%
Series E Perpetual Preferred Shares
Class of Stock [Line Items]
Preferred shares, dividends declared (in dollars per share)	0.40	0.40	0.40	0.40
Preferred stock, dividend rate, percentage					6.35%
Series F Perpetual Preferred Shares
Class of Stock [Line Items]
Preferred shares, dividends declared (in dollars per share)	0.37	0.37	0.37	0.37
Preferred stock, dividend rate, percentage					5.875%
Series G Perpetual Preferred Shares
Class of Stock [Line Items]
Preferred shares, dividends declared (in dollars per share)	0.37	0.37	0.37	0.37
Preferred stock, dividend rate, percentage					5.875%
Series H Perpetual Preferred Shares
Class of Stock [Line Items]
Preferred shares, dividends declared (in dollars per share)	$ 0.39	$ 0.39	$ 0	$ 0
Preferred stock, dividend rate, percentage					6.25%