Segment Reporting Summary of Net Operating Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Straight-line rental income and expense, net	$ 21,197	$ 24,605	$ 16,051
Equity in earnings of unconsolidated joint ventures	31,406	21,444	63,310
Promote income	0	0	20,007
Interest Expense	(89,756)	(85,006)	(87,003)
Depreciation and amortization expense	(327,223)	(312,217)	(273,561)
Gain on sale of properties	234,653	204,988	113,669
Impairment Charges	0	0	(4,481)
Interest and other income, net	9,941	17,234	14,721
General and Administrative Expense	(60,889)	(56,218)	(54,944)
Gain on land sales	7,445	10,334	9,244
Other operating expenses	(5,318)	(5,231)	(4,212)
Loss on debt extinguishment	(6,320)	(388)	(26,104)
Gain on involuntary conversion	(2,259)	0	0
Non-incremental costs related to successful leases	12,402	0	0
Income from continuing operations before income taxes	440,885	392,196	290,235
Operating Segments [Member]
Segment Reporting Information [Line Items]
Property Level Net Operating Income – Cash Basis	603,227	531,903	444,291
PNOI, continuing operations	618,121	564,356	493,943
Operating Segments [Member] | Industrial [Member]
Segment Reporting Information [Line Items]
Property Level Net Operating Income – Cash Basis	599,416	526,627	439,404
Operating Segments [Member] | Non-Reportable Rental Operations
Segment Reporting Information [Line Items]
Property Level Net Operating Income – Cash Basis	3,811	5,276	4,887
Operating Segments [Member] | Earnings from Service Operations
Segment Reporting Information [Line Items]
Earnings from Service Operations	6,360	8,642	4,963
Segment Reconciling Items [Member]
Segment Reporting Information [Line Items]
PNOI from sold properties included in continuing operations	14,894	32,453	49,652
Straight-line rental income and expense, net	21,573	24,604	15,520
Revenues related to lease buyouts	1,235	23	10,816
Amortization of lease concessions and above and below market rents	7,802	2,332	(3,667)
Intercompany rents and other adjusting items	1,012	1,271	1,004
Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Equity in earnings of unconsolidated joint ventures	31,406	21,444	63,310
Promote income	0	0	20,007
Interest Expense	(89,756)	(85,006)	(87,003)
Depreciation and amortization expense	(327,223)	(312,217)	(273,561)
Gain on sale of properties	234,653	204,988	113,669
Impairment Charges	0	0	(4,481)
Interest and other income, net	9,941	17,234	14,721
General and Administrative Expense	(60,889)	(56,218)	(54,944)
Gain on land sales	7,445	10,334	9,244
Other operating expenses	(5,318)	(5,231)	(4,212)
Loss on debt extinguishment	(6,320)	(388)	(26,104)
Gain on involuntary conversion	(2,259)	0	0
Non-incremental costs related to successful leases	(12,402)	0	0
Other non-segment revenues and expenses, net	$ 986	$ (3,972)	$ (2,990)