Acquisitions and Dispositions Dispositions (Details) $ in Thousands	1 Months Ended	9 Months Ended
	Sep. 30, 2019 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)
Dispositions Disclosures [Line Items]
Payments to Acquire Real Estate		$ 146,632	$ 208,914
Proceeds from Sale of Real Estate Held-for-investment		379,774	434,584
Number of Real Estate Properties Sold	18
Proceeds from Sale of Productive Assets	$ 217,500
Gain (Loss) on Sale of Properties	$ 146,300	211,010	$ 205,119
Square Feet of Properties Sold	4,100,000
Proceeds from Collection of Notes Receivable		$ 145,000