Consolidated Variable Interest Entities Consolidated Variable Interest Entities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Sep. 30, 2019	Mar. 31, 2019	Dec. 31, 2018
Variable Interest Entity [Line Items]
Investment property, net	$ 7,232,620	$ 7,232,620		$ 6,118,316
Other assets	219,896	$ 219,896		164,211
Variable Interest Entity, Consolidated, Carrying Amount, Assets	368,194			327,980
Secured debt	3,180,592		$ 3,200,000	2,815,957
Other liabilities	81,289			51,581
Liabilities	3,848,104			3,479,112
Consolidated variable interest entities	$ 8,542			$ 7,145
VIE Percent of Consolidated Assets	4.70%			4.90%
VIE Percent of Consolidated Liabilities	2.50%			2.60%
VIE as a Percentage of Total Equity				1.00%
Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Investment property, net	$ 344,300			$ 308,171
Other assets	23,894			19,809
Secured debt	46,993			44,172
Preferred OP units - mandatorily redeemable	35,249			35,277
Other liabilities	13,631			6,914
Liabilities	95,873			86,363
Equity Interests	27,091			21,976
Consolidated variable interest entities	8,542			7,145
Variable Interest Entities, Consolidated, Total Liabilities and Stockholder's Equity	$ 131,506			$ 115,484