Equity - Distributions (Details) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Dividends Payable
Total distributions paid (usd per share)	$ 4.0700	$ 3.9900	$ 3.9038
Ordinary income
Dividends Payable
Total distributions paid (usd per share)	3.5122	3.2537	3.3075
Capital gains
Dividends Payable
Total distributions paid (usd per share)	0.5578	0.2181	0.0000
Return of capital
Dividends Payable
Total distributions paid (usd per share)	$ 0.0000	$ 0.5182	$ 0.5963