Discontinued Operations and Assets Held for Sale (Tables)

12 Months Ended

Dec. 31, 2017

Discontinued Operations and Disposal Groups [Abstract]

Schedule of Real Estate Properties [Table Text Block]

Real estate assets, excluding assets held for sale, consisted of the following (in thousands):

	December 31, 2017		December 31, 2016
Buildings and tenant improvements	$	4,642,832	$	3,752,423
Land and improvements	1,950,735		1,392,382
Real estate assets	$	6,593,567	$	5,144,805

Table Illustration of Number of Properties in Discontinued Operations

The following table illustrates the number of sold or held-for-sale properties included in, or excluded from, discontinued operations:

	Held-for-Sale at December 31, 2017	Sold in 2017	Sold in 2016	Sold in 2015	Total
Industrial	—	—	—	5	5
Non-Reportable Rental Operations	—	81	—	57	138
Total properties included in discontinued operations	—	81	—	62	143
Properties excluded from discontinued operations	1	17	32	91	141
Total properties sold or classified as held-for-sale	1	98	32	153	284

Table Illustration of Discontinued Operations in Income Statement

The following table illustrates the operational results of the buildings reflected in discontinued operations for the years ended December 31, 2017, 2016 and 2015, respectively (in thousands):

	2017			2016			2015
Revenues	$	87,185		$	172,716		$	189,805
Operating expenses	(28,102		)	(52,795		)	(61,916		)
Depreciation and amortization	(25,911		)	(75,261		)	(75,082		)
Operating income	33,172			44,660			52,807
Interest expense	(14,736		)	(28,819		)	(40,911		)
Income before gain on sales	18,436			15,841			11,896
Gain on sale of depreciable properties	1,357,778			1,016			424,892
Income from discontinued operations before income taxes	1,376,214			16,857			436,788
Income tax expense	(12,465		)	—			(3,175		)
Income from discontinued operations	$	1,363,749		$	16,857		$	433,613

Allocation of Common Shareholders' Income (Loss) Between Continuing and Discontinued Operations

The following table illustrates the General Partner's share of the income attributable to common shareholders from continuing operations and discontinued operations, reduced by the allocation of income between continuing and discontinued operations to noncontrolling interests, for the years ended December 31, 2017, 2016 and 2015, respectively (in thousands):

	2017		2016		2015
Income from continuing operations attributable to common shareholders	$	288,075	$	295,452	$	186,152
Income from discontinued operations attributable to common shareholders	1,346,356		16,691		429,158
Net income attributable to common shareholders	$	1,634,431	$	312,143	$	615,310

Schedule of Discontinued Operations, Properties Held-for-Sale, Aggregate Balance Sheet Information

The following table illustrates aggregate balance sheet information for all held-for-sale properties (in thousands):

	Held-for-Sale Properties
	December 31, 2017				December 31, 2016
		Total			Included in Continuing Operations			Included in Discontinued Operations			Total
Land and improvements		$	8,157		$	3,631		$	118,882		$	122,513
Buildings and tenant improvements		10,505			37,495			1,218,468			1,255,963
Undeveloped land		—			22,657			—			22,657
Accumulated depreciation		(2,553		)	(18,581		)	(240,685		)	(259,266		)
Deferred leasing and other costs, net		862			3,091			83,522			86,613
Other assets		579			3,334			92,444			95,778
Total assets held-for-sale		$	17,550		$	51,627		$	1,272,631		$	1,324,258
Total liabilities held-for-sale		$	1,163		$	1,661		$	54,630		$	56,291

Asset Impairment Charges [Text Block]

The following table illustrates impairment charges recognized during the years ended December 31, 2017, 2016 and 2015, respectively (in thousands):

	2017		2016		2015
Impairment charges - land	$	3,622	$	14,299	$	19,526
Impairment charges - building	859		3,719		3,406
Impairment charges	$	4,481	$	18,018	$	22,932