Investments In Real Estate (Summary Of Wholly Owned Industrial Properties Acquired) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014 sqft property	Dec. 31, 2013	Feb. 11, 2015 property sqft
Real Estate Properties [Line Items]
Number of buildings	126us-gaap_NumberOfRealEstateProperties		11us-gaap_NumberOfRealEstateProperties
Area of real estate property	9,300,000us-gaap_AreaOfRealEstateProperty		641,593us-gaap_AreaOfRealEstateProperty
Total aggregate initial investment	$ 236,700,000	$ 212,400,000
Wholly Owned Properties [Member]
Real Estate Properties [Line Items]
Number of buildings	29	30
Area of real estate property	2,266,082	1,916,394
Purchase price	235,741,000	205,521,000
Wholly Owned Properties [Member] \| SW 34th Street [Member]
Real Estate Properties [Line Items]
Location	Renton, WA
Acquisition Date	Feb. 11, 2014
Number of buildings	1
Area of real estate property	62,004
Purchase price	6,600,000
Wholly Owned Properties [Member] \| Parkway [Member]
Real Estate Properties [Line Items]
Location	Hanover, MD
Acquisition Date	Mar. 26, 2014
Number of buildings	1
Area of real estate property	158,769
Purchase price	18,000,000
Wholly Owned Properties [Member] \| Pulaski [Member]
Real Estate Properties [Line Items]
Location	Bayonne, NJ
Acquisition Date	Mar. 31, 2014
Number of buildings	1
Area of real estate property	98,049
Purchase price	9,200,000
Wholly Owned Properties [Member] \| 747 Glasgow [Member]
Real Estate Properties [Line Items]
Location	Inglewood, CA
Acquisition Date	Apr. 22, 2014
Number of buildings	1
Area of real estate property	19,326
Purchase price	3,450,000
Wholly Owned Properties [Member] \| Hampton [Member]
Real Estate Properties [Line Items]
Location	Capitol Heights, MD
Acquisition Date	May 13, 2014
Number of buildings	1
Area of real estate property	138,780
Purchase price	18,050,000
Wholly Owned Properties [Member] \| Burroughs [Member]
Real Estate Properties [Line Items]
Location	San Leandro, CA
Acquisition Date	May 14, 2014
Number of buildings	3
Area of real estate property	129,279
Purchase price	13,328,000
Wholly Owned Properties [Member] \| California [Member]
Real Estate Properties [Line Items]
Location	Corona, CA
Acquisition Date	Jun. 05, 2014
Number of buildings	1
Area of real estate property	89,819
Purchase price	7,815,000
Wholly Owned Properties [Member] \| Las Hermanas [Member]
Real Estate Properties [Line Items]
Location	Compton, CA
Acquisition Date	Jun. 12, 2014
Number of buildings	1
Area of real estate property	23,735
Purchase price	4,020,000
Wholly Owned Properties [Member] \| South Main II [Member]
Real Estate Properties [Line Items]
Location	Carson, CA
Acquisition Date	Jul. 18, 2014
Number of buildings	1
Area of real estate property	33,769
Purchase price	8,500,000
Wholly Owned Properties [Member] \| 79th Ave South [Member]
Real Estate Properties [Line Items]
Location	Kent, WA
Acquisition Date	Jul. 25, 2014
Number of buildings	1
Area of real estate property	35,018
Purchase price	2,770,000
Wholly Owned Properties [Member] \| Auburn 1307 [Member]
Real Estate Properties [Line Items]
Location	Auburn, WA
Acquisition Date	Aug. 22, 2014
Number of buildings	1
Area of real estate property	91,607
Purchase price	9,530,000
Wholly Owned Properties [Member] \| 3401 Lind [Member]
Real Estate Properties [Line Items]
Location	Renton, WA
Acquisition Date	Oct. 03, 2014
Number of buildings	1
Area of real estate property	113,170
Purchase price	9,975,000
Wholly Owned Properties [Member] \| 900 Hart [Member]
Real Estate Properties [Line Items]
Location	Rahway, NJ
Acquisition Date	Oct. 08, 2014
Number of buildings	1
Area of real estate property	84,000
Purchase price	7,205,000
Wholly Owned Properties [Member] \| Kent 216th [Member]
Real Estate Properties [Line Items]
Location	Kent, WA
Acquisition Date	Oct. 24, 2014
Number of buildings	1
Area of real estate property	106,910
Purchase price	9,214,000
Wholly Owned Properties [Member] \| 9020 Junction [Member]
Real Estate Properties [Line Items]
Location	Annapolis Junction, MD
Acquisition Date	Nov. 17, 2014
Number of buildings	1
Area of real estate property	96,666
Purchase price	13,800,000
Wholly Owned Properties [Member] \| 11300 NW 131st [Member]
Real Estate Properties [Line Items]
Location	Medley, FL
Acquisition Date	Nov. 19, 2014
Number of buildings	1
Area of real estate property	85,000
Purchase price	8,925,000
Wholly Owned Properties [Member] \| Terminal Way [Member]
Real Estate Properties [Line Items]
Location	Avenel, NJ
Acquisition Date	Nov. 25, 2014
Number of buildings	2
Area of real estate property	80,200
Purchase price	7,445,000
Wholly Owned Properties [Member] \| 14605 Miller [Member]
Real Estate Properties [Line Items]
Location	Fontana, CA
Acquisition Date	Dec. 02, 2014
Number of buildings	1
Area of real estate property	265,500
Purchase price	22,899,000
Wholly Owned Properties [Member] \| Park Union City [Member]
Real Estate Properties [Line Items]
Location	Union City, CA
Acquisition Date	Dec. 10, 2014
Number of buildings	3
Area of real estate property	170,129
Purchase price	23,800,000
Wholly Owned Properties [Member] \| 75th Ave [Member]
Real Estate Properties [Line Items]
Location	Landover, MD
Acquisition Date	Dec. 17, 2014
Number of buildings	5
Area of real estate property	384,352
Purchase price	31,215,000
Wholly Owned Properties [Member] \| 107th Avenue [Member]
Real Estate Properties [Line Items]
Location		Medley, FL
Acquisition Date		Mar. 06, 2013
Number of buildings		1
Area of real estate property		49,284
Purchase price		5,095,000
Wholly Owned Properties [Member] \| SeaTac 8th Ave [Member]
Real Estate Properties [Line Items]
Location		Burien, WA
Acquisition Date		Mar. 21, 2013
Number of buildings		1
Area of real estate property		68,583
Purchase price		6,450,000
Wholly Owned Properties [Member] \| 240 Littlefield Avenue [Member]
Real Estate Properties [Line Items]
Location		South San Francisco, CA
Acquisition Date		Apr. 03, 2013
Number of buildings		1
Area of real estate property		67,800
Purchase price		8,400,000
Wholly Owned Properties [Member] \| 101st Road [Member]
Real Estate Properties [Line Items]
Location		Medley, FL
Acquisition Date		Apr. 26, 2013
Number of buildings		1
Area of real estate property		52,536
Purchase price		6,000,000
Wholly Owned Properties [Member] \| Americas Gateway [Member]
Real Estate Properties [Line Items]
Location		Doral, FL
Acquisition Date		May 22, 2013
Number of buildings		6
Area of real estate property		306,924
Purchase price		23,725,000
Wholly Owned Properties [Member] \| Route 100 [Member]
Real Estate Properties [Line Items]
Location		Elkridge, MD
Acquisition Date		Jun. 12, 2013
Number of buildings		2
Area of real estate property		348,610
Purchase price		16,650,000
Wholly Owned Properties [Member] \| 1 Dodge Drive [Member]
Real Estate Properties [Line Items]
Location		West Caldwell, NJ
Acquisition Date		Jun. 20, 2013
Number of buildings		1
Area of real estate property		92,913
Purchase price		6,775,000
Wholly Owned Properties [Member] \| 17 Madison [Member]
Real Estate Properties [Line Items]
Location		Fairfield, NJ
Acquisition Date		Jul. 23, 2013
Number of buildings		1
Area of real estate property		30,792
Purchase price		2,840,000
Wholly Owned Properties [Member] \| 550 Delancy [Member]
Real Estate Properties [Line Items]
Location		Newark, NJ
Acquisition Date		Jul. 25, 2013
Number of buildings		1
Area of real estate property		52,086
Purchase price		15,000,000
Wholly Owned Properties [Member] \| Melanie Lane [Member]
Real Estate Properties [Line Items]
Location		East Hanover, NJ
Acquisition Date		Sep. 30, 2013
Number of buildings		3
Area of real estate property		166,735
Purchase price		20,000,000
Wholly Owned Properties [Member] \| Michele/Meadow [Member]
Real Estate Properties [Line Items]
Location		Carlstadt, NJ
Acquisition Date		Oct. 17, 2013
Number of buildings		2
Area of real estate property		90,225
Purchase price		9,875,000
Wholly Owned Properties [Member] \| 60 Ethel [Member]
Real Estate Properties [Line Items]
Location		Piscataway, NJ
Acquisition Date		Nov. 06, 2013
Number of buildings		2
Area of real estate property		104,930
Purchase price		7,000,000
Wholly Owned Properties [Member] \| 8215 Dorsey [Member]
Real Estate Properties [Line Items]
Location		Jessup, MD
Acquisition Date		Nov. 15, 2013
Number of buildings		1
Area of real estate property		88,438
Purchase price		6,000,000
Wholly Owned Properties [Member] \| 4230 Forbes [Member]
Real Estate Properties [Line Items]
Location		Lanham, MD
Acquisition Date		Dec. 11, 2013
Number of buildings		1
Area of real estate property		55,877
Purchase price		5,600,000
Wholly Owned Properties [Member] \| 14611 Broadway [Member]
Real Estate Properties [Line Items]
Location		Gardena, CA
Acquisition Date		Dec. 19, 2013
Number of buildings		1
Area of real estate property		40,000
Purchase price		6,000,000
Wholly Owned Properties [Member] \| 3601 Pennsy [Member]
Real Estate Properties [Line Items]
Location		Landover, MD
Acquisition Date		Dec. 23, 2013
Number of buildings		1
Area of real estate property		71,400
Purchase price		7,000,000
Wholly Owned Properties [Member] \| JFK Airgate [Member]
Real Estate Properties [Line Items]
Location		Queens, NY
Acquisition Date		Dec. 27, 2013
Number of buildings		4
Area of real estate property		229,261
Purchase price		53,111,000
2014 Acquisition [Member]
Real Estate Properties [Line Items]
Total aggregate initial investment	236,700,000
2014 Acquisition [Member] \| Improved Land Parcel [Member]
Real Estate Properties [Line Items]
Number of buildings	1
Area of real estate property	1.2
2013 Acquisition [Member]
Real Estate Properties [Line Items]
Total aggregate initial investment		$ 212,400,000
2013 Acquisition [Member] \| Improved Land Parcel [Member]
Real Estate Properties [Line Items]
Number of buildings		1
Area of real estate property		2.3