Segment Information (Tables)

12 Months Ended

Dec. 31, 2013

Segment Reporting [Abstract]

Schedule of Segment Reporting Information, by Segment [Table Text Block]

The operating information by reportable segment is as follows (in thousands):

		Year ended
		December 31,
		2013			2012			2011
Operating revenue
Industrial -	Lehigh/Central PA	$	101,101		$	96,804		$	99,311
	Chicago/Milwaukee	18,083			9,780			21,973
	Houston	37,773			30,172			27,325
	Carolinas	30,243			28,667			32,470
	Other	104,387			93,667			101,004
Industrial/Office -	Minnesota	62,415			57,331			55,886
	South Florida	38,464			35,628			36,792
	Richmond/Hampton Roads	40,247			41,395			49,714
	Arizona	26,559			23,033			21,083
	United Kingdom	7,669			4,690			4,408
	Other	81,487			73,126			72,608
Office -	Philadelphia	31,690			28,153			28,129
	Southeastern PA	165,248			169,645			174,063
	Washington D.C.	13,599			5,207			448
Segment-level operating revenue		758,965			697,298			725,214
Reconciliation to total operating revenues
	Discontinued operations	(113,586		)	(137,476		)	(191,723		)
	Other	551			457			208
Total operating revenue		$	645,930		$	560,279		$	533,699
Net operating income
Industrial -	Lehigh/Central PA	$	68,504		$	65,566		$	64,786
	Chicago/Milwaukee	11,726			5,329			10,581
	Houston	22,632			17,862			16,379
	Carolinas	20,434			18,733			19,471
	Other	60,531			51,863			54,802
Industrial/Office -	Minnesota	30,016			26,348			27,701
	South Florida	20,943			18,921			19,431
	Richmond/Hampton Roads	24,063			24,762			29,324
	Arizona	17,189			14,228			13,453
	United Kingdom	1,924			(257		)	(178		)
	Other	50,456			43,711			44,692
Office -	Philadelphia	23,587			20,527			20,504
	Southeastern PA	91,193			98,729			101,982
	Washington D.C.	6,807			2,908			(1,134		)
Segment-level net operating income		450,005			409,230			421,794
Reconciliation to income from continuing operations
	Interest expense (1)	(143,018		)	(123,146		)	(131,046		)
	Depreciation/amortization expense (2)	(138,343		)	(104,643		)	(106,487		)
	Gain on property dispositions	8,676			3,080			5,025
	Equity in earnings (loss) of unconsolidated joint ventures	6,067			(681		)	3,496
	General and administrative expense (2)	(50,998		)	(40,831		)	(36,140		)
	Discontinued operations excluding gain on property dispositions	(26,455		)	(38,578		)	(45,483		)
	Income taxes (2)	(2,748		)	(874		)	(841		)
	Other	(5,431		)	(6,810		)	(5,673		)
Income from continuing operations		$	97,755		$	96,747		$	104,645

(1) Includes interest on discontinued operations.

(2) Excludes costs which are included in determining segment-level net operating income.

Schedule of Segment Reporting Information, by Segment, Depreciation and Amortization [Table Text Block]

The amount of depreciation and amortization expense related to tenant improvement and lease transaction costs within each reporting segment for the Net operating income calculation is as follows:

		Year ended
		December 31,
		2013		2012		2011
Industrial -	Lehigh/Central PA	$	9,781	$	9,753	$	9,821
	Chicago/Milwaukee	251		233		1,695
	Houston	3,200		2,608		2,213
	Carolinas	1,935		1,726		2,194
	Other	10,061		10,461		11,254
Industrial/Office -	Minnesota	5,797		5,132		5,014
	South Florida	2,979		3,083		3,623
	Richmond/Hampton Roads	4,156		4,157		4,820
	Arizona	3,546		3,014		2,694
	United Kingdom	845		269		210
	Other	5,654		5,193		5,217
Office -	Philadelphia	1,729		1,724		1,774
	Southeastern PA	15,040		14,109		13,436
	Washington D.C.	248		156		63
Depreciation and amortization of tenant improvement and lease transaction costs		$	65,222	$	61,618	$	64,028

Revenue from External Customers by Products and Services [Table Text Block]

The Company's operating revenue by product type and by reportable segment for the years ended December 31, 2013, 2012 and 2011 is as follows (in thousands):

		Year Ended
		December 31, 2013							December 31, 2012							December 31, 2011
		Industrial		Office		Total			Industrial		Office		Total			Industrial		Office		Total
Industrial -	Lehigh/Central PA	$	98,715	$	2,386	$	101,101		$	94,440	$	2,364	$	96,804		$	93,193	$	6,118	$	99,311
	Chicago/Milwaukee	18,083		—		18,083			6,908		2,872		9,780			8,239		13,734		21,973
	Houston	37,773		—		37,773			30,172		—		30,172			27,325		—		27,325
	Carolinas	30,243		—		30,243			26,818		1,849		28,667			23,381		9,089		32,470
	Other (1)	44,672		59,715		104,387			32,313		61,354		93,667			33,847		67,157		101,004
Industrial/Office -	Minnesota	32,043		30,372		62,415			27,810		29,521		57,331			24,398		31,488		55,886
	South Florida	7,955		30,509		38,464			5,213		30,415		35,628			5,887		30,905		36,792
	Richmond/Hampton Roads	19,073		21,174		40,247			18,490		22,905		41,395			18,889		30,825		49,714
	Arizona	4,231		22,328		26,559			2,393		20,640		23,033			1,407		19,676		21,083
	United Kingdom	4,205		3,464		7,669			1,307		3,383		4,690			1,288		3,120		4,408
	Other	35,318		46,169		81,487			26,986		46,140		73,126			27,805		44,803		72,608
Office -	Philadelphia	9,534		22,156		31,690			8,356		19,797		28,153			7,817		20,312		28,129
	Southeastern PA	27,076		138,172		165,248			28,604		141,041		169,645			29,289		144,774		174,063
	Washington D.C.	—		13,599		13,599			—		5,207		5,207			—		448		448
		$	368,921	$	390,044	758,965			$	309,810	$	387,488	697,298			$	302,765	$	422,449	725,214
Reconciliation to total operating revenue
Discontinued operations						(113,586		)					(137,476		)					(191,723		)
Corporate Other						551							457							208
Total operating revenue						$	645,930						$	560,279						$	533,699

(1) A substantial portion of the office revenues were sold in conjunction with the Portfolio Sale. See Footnote 23.

Reconciliation of Assets from Segment to Consolidated [Table Text Block]

The Company's total assets by reportable segment as of December 31, 2013 and 2012 is as follows (in thousands):

		As of December 31,
		2013		2012
Total assets
Industrial -	Lehigh/Central PA	$	938,824	$	779,929
	Chicago/Milwaukee	413,585		153,128
	Houston	380,248		266,061
	Carolinas	257,230		249,479
	Other	1,315,732		639,629
Industrial/Office -	Minnesota	335,613		353,428
	South Florida	380,138		227,754
	Richmond/Hampton Roads	250,008		250,600
	Arizona	364,231		300,149
	United Kingdom	247,537		72,323
	Other	465,997		554,352
Office -	Philadelphia	316,810		348,541
	Southeastern PA	695,966		814,460
	Washington D.C.	180,621		50,575
	Corporate Other	233,020		113,771
Total assets		$	6,775,560	$	5,174,179

Schedule of Long-Lived Assets, by Geographical Areas [Table Text Block]

The Company's real estate assets by reportable segment as of December 31, 2013 and 2012 is as follows (in thousands):

		As of December 31,
		2013		2012
Real estate assets
Industrial -	Lehigh/Central PA	$	877,969	$	742,464
	Chicago/Milwaukee	371,149		127,125
	Houston	360,779		252,221
	Carolinas	245,938		239,052
	Other	964,322		323,200
Industrial/Office -	Minnesota	308,272		333,380
	South Florida	358,492		217,769
	Richmond/Hampton Roads	238,129		231,506
	Arizona	348,043		287,895
	United Kingdom	187,699		44,861
	Other	369,935		453,931
Office -	Philadelphia	229,769		266,144
	Southeastern PA	638,211		748,939
	Washington D.C.	170,068		47,820
Total real estate assets		$	5,668,775	$	4,316,307

Schedule of Expenditures on Long-Lived Assets [Table Text Block]

The Company incurred the following costs related to its long-lived assets for the years ended December 31, 2013, 2012 and 2011 (in thousands):

		Year Ended December 31,
		2013		2012		2011
Costs incurred on long-lived assets
Industrial -	Lehigh/Central PA	$	161,925	$	86,245	$	66,472
	Chicago/Milwaukee	248,640		49,941		55,077
	Houston	116,024		46,003		10,188
	Carolinas	15,582		26,860		85,732
	Other	664,008		21,065		13,006
Industrial/Office -	Minnesota	38,434		41,821		45,595
	South Florida	148,165		3,337		23,493
	Richmond/Hampton Roads	15,880		8,612		5,920
	Arizona	68,138		35,750		8,794
	United Kingdom	155,829		6,110		4,838
	Other	79,813		80,402		4,914
Office -	Philadelphia	17,941		93,673		49,407
	Southeastern PA	39,590		11,577		14,851
	Washington D.C.	125,480		621		48,786
Total costs incurred on long-lived assets		$	1,895,449	$	512,017	$	437,073