Investment in Real Estate Inestment in Real Estate - Summary of Industrial Property Dispositions (Details) $ in Thousands, ft² in Millions		12 Months Ended
		Dec. 31, 2019 USD ($) ft² Property	Dec. 31, 2018 USD ($) ft² Property	Dec. 31, 2017 USD ($) ft² Property
Real Estate Properties [Line Items]
Number of industrial properties | Property		440
Gross leasable area (GLA) of industrial properties		61.3
Proceeds from sale of industrial properties | $	[1]	$ 315,768	$ 192,047	$ 236,059
Gain on sale of real estate | $	[1]	$ 124,942	$ 81,600	$ 131,269
Partial Disposition Activity
Real Estate Properties [Line Items]
Gross leasable area (GLA) of industrial properties		0.1	0.1
Disposition Activity
Real Estate Properties [Line Items]
Number of industrial properties | Property	[2]	40	53	60
Gross leasable area (GLA) of industrial properties		5.9	2.6	4.6

[1] ^(B) Gross proceeds and gain on sale of real estate include the sale of several land parcels for the years ended December 31, 2019, 2018 and 2017. In addition, included in the above table for the year ended December 31, 2019, is gross proceeds of $54,521 and gain on sale of $8,606 related to the reclassification of a lease from an operating lease to a sales-type lease. See Note 10 for additional information.

[2] ^(A) The years ended December 31, 2019 and 2018 include partial sales of 0.1 million and 0.1 million square-foot industrial properties, respectively.