Subsequent Events (Details) $ / shares in Units, $ in Thousands		1 Months Ended	3 Months Ended		9 Months Ended
	Nov. 01, 2018 $ / shares	Oct. 31, 2018 USD ($) property	Sep. 30, 2018 $ / shares	Sep. 30, 2017 $ / shares	Sep. 30, 2018 USD ($) $ / shares	Sep. 30, 2017 USD ($) $ / shares	Nov. 02, 2018 USD ($)
Subsequent Event [Line Items]
Proceeds from the sale of real estate properties | $					$ 47,757	$ 68,618
Quarterly dividend (in dollars per share)			$ 0.05	$ 0.05	$ 0.15	$ 0.15
Class A common shares/units
Subsequent Event [Line Items]
Quarterly dividend (in dollars per share)			0.05	0.05
Class B common shares
Subsequent Event [Line Items]
Quarterly dividend (in dollars per share)			0.05	0.05
Series D Perpetual Preferred Shares/Units
Subsequent Event [Line Items]
Preferred stock dividends declared (in dollars per share)			$ 0.41	$ 0.41
Preferred stock, dividend rate, percentage			6.50%	6.50%	6.50%
Series E Perpetual Preferred Shares
Subsequent Event [Line Items]
Preferred stock dividends declared (in dollars per share)			$ 0.40	$ 0.40
Preferred stock, dividend rate, percentage			6.35%	6.35%	6.35%
Series F Perpetual Preferred Shares
Subsequent Event [Line Items]
Preferred stock dividends declared (in dollars per share)			$ 0.37	$ 0.37
Preferred stock, dividend rate, percentage			5.875%	5.875%	5.875%
Series G Perpetual Preferred Shares
Subsequent Event [Line Items]
Preferred stock dividends declared (in dollars per share)			$ 0.37	$ 0.30
Preferred stock, dividend rate, percentage			5.875%		5.875%
Series H Perpetual Preferred Shares
Subsequent Event [Line Items]
Preferred stock, dividend rate, percentage			6.25%		6.25%
Subsequent Event
Subsequent Event [Line Items]
Number of properties acquired | property		221
Purchase price to acquire real estate | $		$ 55,100
Number of internally developed properties developed | property		12
Number of real estate properties sold | property		138
Proceeds from the sale of real estate properties | $		$ 21,200
Subsequent Event | Hurricane Michael | Minimum
Subsequent Event [Line Items]
Estimate of possible loss | $							$ 400
Subsequent Event | Hurricane Michael | Maximum
Subsequent Event [Line Items]
Estimate of possible loss | $							$ 700
Subsequent Event | Class A common shares/units
Subsequent Event [Line Items]
Quarterly dividend (in dollars per share)	$ 0.05
Subsequent Event | Class B common shares
Subsequent Event [Line Items]
Quarterly dividend (in dollars per share)	0.05
Subsequent Event | Series D Perpetual Preferred Shares/Units
Subsequent Event [Line Items]
Preferred stock dividends declared (in dollars per share)	0.40625
Subsequent Event | Series E Perpetual Preferred Shares
Subsequent Event [Line Items]
Preferred stock dividends declared (in dollars per share)	0.39688
Subsequent Event | Series F Perpetual Preferred Shares
Subsequent Event [Line Items]
Preferred stock dividends declared (in dollars per share)	0.36719
Subsequent Event | Series G Perpetual Preferred Shares
Subsequent Event [Line Items]
Preferred stock dividends declared (in dollars per share)	0.36719
Subsequent Event | Series H Perpetual Preferred Shares
Subsequent Event [Line Items]
Preferred stock dividends declared (in dollars per share)	0.44271
Preferred stock, dividend rate, prorated amount, percentage	$ 0.05