STORAGE FACILITIES (Details 2) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014 property	Dec. 31, 2013 property	Dec. 31, 2012 property
Acquisitions
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)	53	20	37
Purchase / Sales Price	$ 568,226	$ 189,822	$ 432,340
Acquisitions \| Connecticut Asset Two
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)	1
Purchase / Sales Price	4,950
Acquisitions \| Florida Asset One
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)	1
Purchase / Sales Price	14,000
Acquisitions \| Florida Assets Two
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)	2
Purchase / Sales Price	14,450
Acquisitions \| California Asset
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)	1
Purchase / Sales Price	8,300
Acquisitions \| Maryland Asset One
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)		1
Purchase / Sales Price		15,375
Acquisitions \| Maryland Asset Two
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)		1
Purchase / Sales Price		8,200
Acquisitions \| Maryland Asset Three
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)	1
Purchase / Sales Price	15,800
Acquisitions \| Maryland Asset Four
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)	1
Purchase / Sales Price	15,500
Acquisitions \| Arizona Asset One
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)	1
Purchase / Sales Price	14,750
Acquisitions \| Pennsylvania Asset
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)	1
Purchase / Sales Price	7,350
Acquisitions \| Texas Asset One
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)	1
Purchase / Sales Price	8,225
Acquisitions \| Texas Asset Two
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)	1
Purchase / Sales Price	6,450
Acquisitions \| New York Asset One
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)	2
Purchase / Sales Price	55,000
Acquisitions \| Florida Asset Three
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)	1
Purchase / Sales Price	11,406
Acquisitions \| Massachusetts Asset One
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)	1
Purchase / Sales Price	11,100
Acquisitions \| Indiana Asset
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)	1
Purchase / Sales Price	8,400
Acquisitions \| Florida Assets Four
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)	3
Purchase / Sales Price	35,000
Acquisitions \| Florida Assets Five
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)	2
Purchase / Sales Price	15,800
Acquisitions \| Massachusetts Asset Two
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)	1
Purchase / Sales Price	23,100
Acquisitions \| Texas Asset Three
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)	1
Purchase / Sales Price	7,700
Acquisitions \| Texas Asset Four
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)	1
Purchase / Sales Price	8,500
Acquisitions \| Texas Asset Five
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)	1
Purchase / Sales Price	7,750
Acquisitions \| HSRE Assets
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)	22
Purchase / Sales Price	195,500
Acquisitions \| Texas Asset Six
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)	1
Purchase / Sales Price	18,650
Acquisitions \| Florida Assets Six
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)	3
Purchase / Sales Price	18,200
Acquisitions \| New York Asset Two
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)	1
Purchase / Sales Price	38,000
Acquisitions \| Texas Asset Seven
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)	1
Purchase / Sales Price	4,345
Acquisitions \| Arizona Asset Two
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)		1
Purchase / Sales Price		6,900
Acquisitions \| Illinois Asset
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)		1
Purchase / Sales Price		8,300
Acquisitions \| Florida Asset Seven
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)		1
Purchase / Sales Price		7,150
Acquisitions \| Florida Asset Eight
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)		1
Purchase / Sales Price		9,000
Acquisitions \| Massachusetts Asset
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)		1
Purchase / Sales Price		10,600
Acquisitions \| Maryland / New Jersey Assets
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)		5
Purchase / Sales Price		52,400
Acquisitions \| New York Asset Three
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)		1
Purchase / Sales Price		13,000
Acquisitions \| Texas Asset Eight
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)		1
Purchase / Sales Price		10,975
Acquisitions \| Arizona Asset Three
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)		1
Purchase / Sales Price		10,500
Acquisitions \| Arizona Asset Four
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)		1
Purchase / Sales Price		4,300
Acquisitions \| Texas Asset Nine
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)		1
Purchase / Sales Price		9,700
Acquisitions \| Texas Asset Ten
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)		1
Purchase / Sales Price		10,497
Acquisitions \| Texas Asset Eleven
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)		1
Purchase / Sales Price		6,925
Acquisitions \| Florida Asset Nine
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)		1
Purchase / Sales Price		6,000
Acquisitions \| Texas Asset Twelve
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)			1
Purchase / Sales Price			5,100
Acquisitions \| Georgia Asset One
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)			1
Purchase / Sales Price			6,900
Acquisitions \| Texas Asset Thirteen
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)			1
Purchase / Sales Price			4,970
Acquisitions \| Texas Assets Fourteen
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)			4
Purchase / Sales Price			18,150
Acquisitions \| Texas Asset Fifteen
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)			1
Purchase / Sales Price			5,130
Acquisitions \| Storage Deluxe assets
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)			6
Purchase / Sales Price			201,910
Acquisitions \| Connecticut Asset
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)			1
Purchase / Sales Price			5,000
Acquisitions \| Virginia Asset
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)			1
Purchase / Sales Price			19,750
Acquisitions \| New Jersey Assets
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)			2
Purchase / Sales Price			10,750
Acquisitions \| Georgia/Florida Assets
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)			3
Purchase / Sales Price			13,370
Acquisitions \| Georgia Asset Two
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)			1
Purchase / Sales Price			3,100
Acquisitions \| HSREV Assets
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)			9
Purchase / Sales Price			102,000
Acquisitions \| Colorado Asset
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)			1
Purchase / Sales Price			10,600
Acquisitions \| Florida Assets Ten
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)			2
Purchase / Sales Price			13,010
Acquisitions \| Pennsylvania/New Jersey Assets
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)			2
Purchase / Sales Price			7,800
Acquisitions \| Texas Asset Sixteen
STORAGE FACILITIES
Number of Facilities, acquisitions (in properties)			1
Purchase / Sales Price			4,800
Dispositions
STORAGE FACILITIES
Number of Facilities, dispositions (in properties)		35	26
Purchase / Sales Price		126,400	59,962
Dispositions \| California Asset
STORAGE FACILITIES
Number of Facilities, dispositions (in properties)			1
Purchase / Sales Price			5,000
Dispositions \| Texas/Indiana Assets
STORAGE FACILITIES
Number of Facilities, dispositions (in properties)		5
Purchase / Sales Price		11,400
Dispositions \| Tennessee Assets
STORAGE FACILITIES
Number of Facilities, dispositions (in properties)		8
Purchase / Sales Price		25,000
Dispositions \| California/Tennessee/Texas Assets/Wisconsin Assets
STORAGE FACILITIES
Number of Facilities, dispositions (in properties)		22
Purchase / Sales Price		90,000
Dispositions \| Michigan Assets
STORAGE FACILITIES
Number of Facilities, dispositions (in properties)			3
Purchase / Sales Price			6,362
Dispositions \| Alabama/Louisiana/Mississippi Assets
STORAGE FACILITIES
Number of Facilities, dispositions (in properties)			5
Purchase / Sales Price			16,800
Dispositions \| New Mexico Assets
STORAGE FACILITIES
Number of Facilities, dispositions (in properties)			6
Purchase / Sales Price			7,500
Dispositions \| Florida/ Tennessee Assets
STORAGE FACILITIES
Number of Facilities, dispositions (in properties)			3
Purchase / Sales Price			6,550
Dispositions \| Ohio Assets
STORAGE FACILITIES
Number of Facilities, dispositions (in properties)			8
Purchase / Sales Price			$ 17,750