Shareholders' Equity / Partners' Capital - Share Repurchase (Details) - USD ($)	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Feb. 28, 2018
Class A common shares/units
Class of Stock [Line Items]
Repurchase of shares, authorized amount			$ 300,000,000.0
Average price per share of Class A common shares (in dollars per share)		$ 19.36
Stock repurchased and retired during period		$ 34,900,000
Remaining repurchase authorization	$ 265,100,000
Class A common shares/units | Common Stock
Class of Stock [Line Items]
Repurchases of Class A common shares (in shares)	0	1,800,000
Preferred Shares/Units
Class of Stock [Line Items]
Repurchase of shares, authorized amount	$ 250,000,000.0		$ 250,000,000.0