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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.10)
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Reference 2: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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Amount of gain (loss) on sale or disposal of property, plant and equipment assets, excluding oil and gas property and timber property.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (b)
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Reference 2: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 3
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Aggregate of the carrying amounts as of the balance sheet date of investments in building and building improvements.

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Amount before accumulated depletion of real estate held for productive use, excluding land held for sale.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section 45
-Paragraph 4
-Subparagraph (e)
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-Name Accounting Standards Codification
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Amount of real estate investment property 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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Investment in Real Estate (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2016	Dec. 31, 2015
Investment in Real Estate
Land		$ 82,463	$ 74,819
Buildings and Improvements		1,186,712	1,037,127
Construction in progress		272,928	$ 183,189
Total investments in real estate		1,542,103
Gain on real estate disposal	$ 36
Boston
Investment in Real Estate
Land		5,154
Buildings and Improvements		96,202
Construction in progress		459
Total investments in real estate		101,815
Chicago
Investment in Real Estate
Land		5,493
Buildings and Improvements		98,549
Construction in progress		2,159
Total investments in real estate		106,201
Denver
Investment in Real Estate
Buildings and Improvements		4,878
Construction in progress		2,068
Total investments in real estate		6,946
Los Angeles
Investment in Real Estate
Land		28,467
Buildings and Improvements		232,825
Construction in progress		3,439
Total investments in real estate		264,731
Miami
Investment in Real Estate
Land		728
Buildings and Improvements		10,482
Construction in progress		2
Total investments in real estate		11,212
New York
Investment in Real Estate
Land		2,388
Buildings and Improvements		127,842
Construction in progress		38,096
Total investments in real estate		168,326
Northern Virginia
Investment in Real Estate
Land		12,442
Buildings and Improvements		246,606
Construction in progress		7,380
Total investments in real estate		266,428
San Francisco Bay
Investment in Real Estate
Land		27,791
Buildings and Improvements		369,328
Construction in progress		219,325
Total investments in real estate		$ 616,444