Real Estate (Tables)

12 Months Ended

Dec. 31, 2015

Real Estate [Abstract]

Real Estate Investment Property, Net [Table Text Block]

The carrying value of these properties by type as of December 31, 2015 and 2014 is as follows (in thousands):

	Land		Building
	and Land		and				Accumulated
	Improvements		Improvements		Total		Depreciation
2015
Industrial properties	$	824,140	$	3,637,484	$	4,461,624	$	698,456
Office properties	360,787		1,494,164		1,854,951		450,472
2015 Total	$	1,184,927	$	5,131,648	$	6,316,575	$	1,148,928
2014
Industrial properties	$	773,874	$	3,513,534	$	4,287,408	$	620,967
Office properties	414,900		1,825,780		2,240,680		561,162
2014 Total	$	1,188,774	$	5,339,314	$	6,528,088	$	1,182,129

Real Estate Properties Sold [Table Text Block]

Information on the operating properties the Company sold during the years ended December 31, 2015 and 2014 is as follows:

2015 Sales

Reportable Segment	Number of Buildings	Acres of Developable Land (unaudited)	Leaseable Square Feet (unaudited)	Gross Proceeds (in thousands)
Minnesota	2	—	222,642	$	25,700
Orlando	1	—	713,585	35,500
Richmond/Hampton Roads	22	3	1,319,299	110,054
South Florida	1	—	99,740	14,700
Southeastern PA	46	20	2,724,489	316,583
Tampa	2	—	60,800	5,225
Other	7	—	569,618	37,371
Total	81	23	5,710,173	$	545,133

2014 Sales

Reportable Segment	Number of Buildings	Acres of Developable Land (unaudited)	Leaseable Square Feet (unaudited)	Gross Proceeds (in thousands)
Houston	5	—	553,510	$	29,721
Maryland	23	19	1,367,569	185,460
Minnesota	1	—	191,336	41,000
New Jersey	27	51	1,790,893	164,767
Orlando	4	—	588,678	116,750
Southeastern PA	3	—	113,833	12,225
Other	2	—	134,510	8,655
Total	65	70	4,740,329	$	558,578

A summary of the results of operations for the properties classified as discontinued operations through the respective disposition dates is as follows (in thousands):

	For the Year Ended December 31,
	2015		2014			2013
Revenues	$	—	$	4,728		$	113,586
Operating expenses	—		(2,258		)	(41,875		)
Interest and other income	—		37			213
Interest expense	—		(557		)	(15,903		)
Depreciation and amortization	—		—			(29,566		)
Income before gain on property dispositions	—		1,950			26,455
Gain on property dispositions	—		46,631			95,384
Net income	$	—	$	48,581		$	121,839

Schedule of Business Acquisitions, by Acquisition [Table Text Block]

Information on the operating properties and land parcels the Company acquired during the years ended December 31, 2015 and 2014 is as follows:

2015 Acquisitions

Reportable Segment	Number of Buildings	Acres of Developable Land (unaudited)	Leaseable Square Feet (unaudited)	Purchase Price
				(in thousands)
Houston	3	139	921,196	$	86,497
Lehigh/Central PA	—	281	—	62,402
Minnesota	1	188	197,956	24,541
Richmond/Hampton Roads	—	94	—	1,727
Other	1	56	410,059	45,248
Total	5	758	1,529,211	$	220,415

2014 Acquisitions

Reportable Segment	Number of Buildings	Acres of Developable Land (unaudited)	Leaseable Square Feet (unaudited)	Purchase Price
				(in thousands)
Carolinas	7	104	947,365	$	61,293
Chicago/Milwaukee	—	16	—	7,914
Houston	—	110	—	26,210
Lehigh/Central PA	—	85	—	15,307
Minnesota	—	24	—	2,966
South Florida	—	69	—	12,027
Other	3	94	981,243	86,476
Total	10	502	1,928,608	$	212,193

The following table summarizes the estimated fair values of the assets acquired and liabilities assumed at the acquisition date.

Assets
Real estate:
Land and land improvements	$	247,393
Building and improvements	1,152,717
Operating real estate	1,400,110
Intangible - in-place leases/market rent	97,396
Other assets	4,953
Total assets	1,502,459
Liabilities
Mortgage loans	243,230
Other liabilities	32,958
Intangible - market rent	5,737
Total liabilities	281,925
Net assets acquired	$	1,220,534