Acquisitions and Developments in Progress - Acquisition Date Fair Values (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2017	Dec. 31, 2018
2019 acquisitions
Acquisition Date Fair Values
Land	$ 14,819
Developments in progress	0
Building and other improvements, net	13,667
Acquired lease intangible assets	2,040
Acquired lease intangible liabilities	(234)
Other liabilities	0
Net assets acquired	$ 30,292
Weighted average amortization period, acquired lease intangible assets	6 years
Weighted average amortization period, acquired lease intangible liabilities	5 years
2018 acquisitions
Acquisition Date Fair Values
Land			$ 0
Developments in progress			25,450
Building and other improvements, net			0
Acquired lease intangible assets			0
Acquired lease intangible liabilities			0
Other liabilities			0
Net assets acquired			$ 25,450
2017 acquisitions
Acquisition Date Fair Values
Land		$ 50,876
Developments in progress		0
Building and other improvements, net		148,108
Acquired lease intangible assets		15,608
Acquired lease intangible liabilities		(8,095)
Other liabilities		(1,076)
Net assets acquired		$ 205,421
Weighted average amortization period, acquired lease intangible assets		7 years
Weighted average amortization period, acquired lease intangible liabilities		13 years