Land, Buildings and Improvements and Assets Held for Sale - Property Plant and Equipment (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Real Estate Investment Property At Cost
Less: Accumulated depreciation	$ (1,812,628)	$ (1,564,182)
Investments in real estate	13,800,409	13,493,036
Operating Properties
Real Estate Investment Property At Cost
Land	39,675	102,478
Buildings and improvements	149,618	363,572
Real estate under construction	0	4,620
Less: Accumulated depreciation	(11,179)	(10,234)
Investments in real estate	178,114	460,436
Assets Leased to Others
Real Estate Investment Property At Cost
Land	1,830,922	1,772,099
Buildings and improvements	7,409,650	6,945,513
Real estate under construction	50,441	63,114
Less: Accumulated depreciation	(836,360)	(724,550)
Investments in real estate	$ 8,454,653	$ 8,056,176

The current amount of expenditures for a real estate project that has not yet been completed.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
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Aggregate of the carrying amounts as of the balance sheet date of investments in building and building improvements.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Amount before accumulated depletion of real estate held for productive use, excluding land held for sale.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
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The cumulative amount of depreciation for real estate property held for investment purposes.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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No definition available.

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Amount of real estate investment property, net of accumulated depreciation, which may include the following: (1) land available-for-sale; (2) land available-for-development; (3) investments in building and building improvements; (4) tenant allowances; (5) developments in-process; (6) rental properties; and (7) other real estate investments.

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