REAL ESTATE PROPERTIES 3 (Details) (USD $)	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013	Dec. 31, 2012
DEVELOPMENT [Abstract]
Interest costs capitalized on development properties	$ 4,942,000		$ 5,064,000	$ 4,660,000
Internal Development Costs Capitalized During Period	4,040,000		3,730,000	2,810,000
Improvements on developments transferred to real estate properties	6,950,000
Development costs incurred, for the period	97,696,000		76,240,000	55,404,000
Development	179,973,000		148,767,000
Future Minimum payments receivable [Abstract]
2015	163,356,000
2016	130,512,000
2017	99,822,000
2018	72,788,000
2019	53,451,000
Thereafter	91,343,000
Total minimum receipts	611,272,000
Lease Up [Member]
DEVELOPMENT [Abstract]
Size (Unaudited) (Square feet)	940,000
Development Costs Transferred	9,370,000	[1]
Development costs incurred, for the period	40,865,000
Development	62,231,000
Estimated Total Cumulative Development Costs	71,900,000	[2]
Under construction [Member]
DEVELOPMENT [Abstract]
Size (Unaudited) (Square feet)	861,000
Development Costs Transferred	11,191,000	[1]
Development costs incurred, for the period	20,464,000
Development	31,655,000
Estimated Total Cumulative Development Costs	60,600,000	[2]
Prospective Development [Member]
DEVELOPMENT [Abstract]
Size (Unaudited) (Square feet)	5,003,000
Development Costs Transferred	(22,173,000)	[1]
Development costs incurred, for the period	8,654,000
Development	86,087,000
Estimated Total Cumulative Development Costs	342,800,000	[2]
Prospective Development [Member] | Phoenix Area [Member]
DEVELOPMENT [Abstract]
Size (Unaudited) (Square feet)	286,000
Development Costs Transferred	(2,353,000)	[1]
Development costs incurred, for the period	1,443,000
Development	3,463,000
Estimated Total Cumulative Development Costs	21,600,000	[2]
Prospective Development [Member] | Tucson [Member]
DEVELOPMENT [Abstract]
Size (Unaudited) (Square feet)	70,000
Development Costs Transferred	0	[1]
Development costs incurred, for the period	0
Development	417,000
Estimated Total Cumulative Development Costs	5,300,000	[2]
Prospective Development [Member] | Fort Myers [Member]
DEVELOPMENT [Abstract]
Size (Unaudited) (Square feet)	663,000
Development Costs Transferred	0	[1]
Development costs incurred, for the period	0
Development	17,858,000
Estimated Total Cumulative Development Costs	50,000,000	[2]
Prospective Development [Member] | Orlando [Member]
DEVELOPMENT [Abstract]
Size (Unaudited) (Square feet)	1,144,000
Development Costs Transferred	(2,526,000)	[1]
Development costs incurred, for the period	1,703,000
Development	23,851,000
Estimated Total Cumulative Development Costs	82,600,000	[2]
Prospective Development [Member] | Tampa [Member]
DEVELOPMENT [Abstract]
Size (Unaudited) (Square feet)	392,000
Development Costs Transferred	(951,000)	[1]
Development costs incurred, for the period	313,000
Development	6,184,000
Estimated Total Cumulative Development Costs	23,100,000	[2]
Prospective Development [Member] | Jackson area [Member]
DEVELOPMENT [Abstract]
Size (Unaudited) (Square feet)	28,000
Development Costs Transferred	0	[1]
Development costs incurred, for the period	0
Development	706,000
Estimated Total Cumulative Development Costs	2,000,000	[2]
Prospective Development [Member] | Charlotte [Member]
DEVELOPMENT [Abstract]
Size (Unaudited) (Square feet)	384,000
Development Costs Transferred	(3,110,000)	[1]
Development costs incurred, for the period	739,000
Development	4,983,000
Estimated Total Cumulative Development Costs	26,800,000	[2]
Prospective Development [Member] | Dallas [Member]
DEVELOPMENT [Abstract]
Size (Unaudited) (Square feet)	169,000
Development Costs Transferred	(3,039,000)	[1]
Development costs incurred, for the period	3,439,000
Development	1,649,000
Estimated Total Cumulative Development Costs	11,200,000	[2]
Prospective Development [Member] | El Paso [Member]
DEVELOPMENT [Abstract]
Size (Unaudited) (Square feet)	251,000
Development Costs Transferred	0	[1]
Development costs incurred, for the period	0
Development	2,444,000
Estimated Total Cumulative Development Costs	11,300,000	[2]
Prospective Development [Member] | Houston [Member]
DEVELOPMENT [Abstract]
Size (Unaudited) (Square feet)	1,362,000
Development Costs Transferred	(6,864,000)	[1]
Development costs incurred, for the period	415,000
Development	21,710,000
Estimated Total Cumulative Development Costs	92,200,000	[2]
Prospective Development [Member] | San Antonio [Member]
DEVELOPMENT [Abstract]
Size (Unaudited) (Square feet)	254,000
Development Costs Transferred	(3,330,000)	[1]
Development costs incurred, for the period	602,000
Development	2,822,000
Estimated Total Cumulative Development Costs	16,700,000	[2]
Development completed and transferred to Real estate properties [Member]
DEVELOPMENT [Abstract]
Size (Unaudited) (Square feet)	949,000
Development Costs Transferred	1,612,000	[1]
Development costs incurred, for the period	20,763,000
Development	59,540,000	[3]
Development completed and transferred to Real estate properties [Member] | Chandler Freeways [Member]
DEVELOPMENT [Abstract]
Size (Unaudited) (Square feet)	126,000
Development Costs Transferred	0	[1]
Development costs incurred, for the period	0
Development	7,858,000	[3]
Completion date (or anticipated completion date, if under construction)	11/13
Development completed and transferred to Real estate properties [Member] | Steele Creek I [Member]
DEVELOPMENT [Abstract]
Size (Unaudited) (Square feet)	71,000
Development Costs Transferred	0	[1]
Development costs incurred, for the period	(46,000)
Development	4,221,000	[3]
Completion date (or anticipated completion date, if under construction)	02/14
Development completed and transferred to Real estate properties [Member] | Ten West Crossing 3 [Member]
DEVELOPMENT [Abstract]
Size (Unaudited) (Square feet)	68,000
Development Costs Transferred	0	[1]
Development costs incurred, for the period	544,000
Development	4,913,000	[3]
Completion date (or anticipated completion date, if under construction)	09/13
Development completed and transferred to Real estate properties [Member] | Thousand Oaks 3 [Member]
DEVELOPMENT [Abstract]
Size (Unaudited) (Square feet)	66,000
Development Costs Transferred	0	[1]
Development costs incurred, for the period	684,000
Development	4,984,000	[3]
Completion date (or anticipated completion date, if under construction)	07/13
Development completed and transferred to Real estate properties [Member] | Ten West Crossing 2 [Member]
DEVELOPMENT [Abstract]
Size (Unaudited) (Square feet)	46,000
Development Costs Transferred	0	[1]
Development costs incurred, for the period	860,000
Development	4,949,000	[3]
Completion date (or anticipated completion date, if under construction)	09/13
Development completed and transferred to Real estate properties [Member] | Ten West Crossing 4 [Member]
DEVELOPMENT [Abstract]
Size (Unaudited) (Square feet)	68,000
Development Costs Transferred	0	[1]
Development costs incurred, for the period	1,350,000
Development	4,811,000	[3]
Completion date (or anticipated completion date, if under construction)	02/14
Development completed and transferred to Real estate properties [Member] | Ten West Crossing 5 [Member]
DEVELOPMENT [Abstract]
Size (Unaudited) (Square feet)	101,000
Development Costs Transferred	0	[1]
Development costs incurred, for the period	4,652,000
Development	6,064,000	[3]
Completion date (or anticipated completion date, if under construction)	09/14
Development completed and transferred to Real estate properties [Member] | World Houston 37 [Member]
DEVELOPMENT [Abstract]
Size (Unaudited) (Square feet)	101,000
Development Costs Transferred	0	[1]
Development costs incurred, for the period	1,291,000
Development	6,670,000	[3]
Completion date (or anticipated completion date, if under construction)	09/13
Development completed and transferred to Real estate properties [Member] | World Houston 40 [Member]
DEVELOPMENT [Abstract]
Size (Unaudited) (Square feet)	202,000
Development Costs Transferred	0	[1]
Development costs incurred, for the period	7,020,000
Development	9,050,000	[3]
Completion date (or anticipated completion date, if under construction)	09/14
Development completed and transferred to Real estate properties [Member] | West Road II [Member]
DEVELOPMENT [Abstract]
Size (Unaudited) (Square feet)	100,000
Development Costs Transferred	1,612,000	[1]
Development costs incurred, for the period	4,408,000
Development	6,020,000	[3]
Completion date (or anticipated completion date, if under construction)	10/14
Lease Up Construction And Prospective Development [Member]
DEVELOPMENT [Abstract]
Size (Unaudited) (Square feet)	6,804,000
Development Costs Transferred	(1,612,000)	[1]
Development costs incurred, for the period	69,983,000
Development	179,973,000
Estimated Total Cumulative Development Costs	475,300,000	[2]
Development obligations	25,300,000
Tenant improvement obligations	2,600,000
Horizon I [Member] | Lease Up [Member]
DEVELOPMENT [Abstract]
Size (Unaudited) (Square feet)	109,000
Development Costs Transferred	0	[1]
Development costs incurred, for the period	1,811,000
Development	7,112,000
Estimated Total Cumulative Development Costs	7,700,000	[2]
Completion date (or anticipated completion date, if under construction)	02/14
Steele Creek II [Member] | Lease Up [Member]
DEVELOPMENT [Abstract]
Size (Unaudited) (Square feet)	71,000
Development Costs Transferred	0	[1]
Development costs incurred, for the period	1,582,000
Development	4,923,000
Estimated Total Cumulative Development Costs	5,600,000	[2]
Completion date (or anticipated completion date, if under construction)	03/14
World Houston 39 [Member] | Lease Up [Member]
DEVELOPMENT [Abstract]
Size (Unaudited) (Square feet)	94,000
Development Costs Transferred	0	[1]
Development costs incurred, for the period	3,420,000
Development	5,056,000
Estimated Total Cumulative Development Costs	5,700,000	[2]
Completion date (or anticipated completion date, if under construction)	06/14
Steele Creek III [Member] | Lease Up [Member]
DEVELOPMENT [Abstract]
Size (Unaudited) (Square feet)	108,000
Development Costs Transferred	2,172,000	[1]
Development costs incurred, for the period	5,148,000
Development	7,320,000
Estimated Total Cumulative Development Costs	8,200,000	[2]
Completion date (or anticipated completion date, if under construction)	07/14
World Houston 41 [Member] | Lease Up [Member]
DEVELOPMENT [Abstract]
Size (Unaudited) (Square feet)	104,000
Development Costs Transferred	1,184,000	[1]
Development costs incurred, for the period	4,162,000
Development	5,346,000
Estimated Total Cumulative Development Costs	6,900,000	[2]
Completion date (or anticipated completion date, if under construction)	08/14
Horizon II [Member] | Lease Up [Member]
DEVELOPMENT [Abstract]
Size (Unaudited) (Square feet)	123,000
Development Costs Transferred	2,526,000	[1]
Development costs incurred, for the period	5,134,000
Development	7,660,000
Estimated Total Cumulative Development Costs	8,600,000	[2]
Completion date (or anticipated completion date, if under construction)	09/14
Ten West Crossing 6 [Member] | Lease Up [Member]
DEVELOPMENT [Abstract]
Size (Unaudited) (Square feet)	64,000
Development Costs Transferred	928,000	[1]
Development costs incurred, for the period	3,314,000
Development	4,242,000
Estimated Total Cumulative Development Costs	4,800,000	[2]
Completion date (or anticipated completion date, if under construction)	10/14
West Road I [Member] | Lease Up [Member]
DEVELOPMENT [Abstract]
Size (Unaudited) (Square feet)	63,000
Development Costs Transferred	1,014,000	[1]
Development costs incurred, for the period	3,263,000
Development	4,277,000
Estimated Total Cumulative Development Costs	4,900,000	[2]
Completion date (or anticipated completion date, if under construction)	10/14
Kyrene 202 I [Member] | Lease Up [Member]
DEVELOPMENT [Abstract]
Size (Unaudited) (Square feet)	75,000
Development Costs Transferred	971,000	[1]
Development costs incurred, for the period	4,968,000
Development	5,939,000
Estimated Total Cumulative Development Costs	6,900,000	[2]
Completion date (or anticipated completion date, if under construction)	11/14
Kyrene 202 II [Member] | Lease Up [Member]
DEVELOPMENT [Abstract]
Size (Unaudited) (Square feet)	45,000
Development Costs Transferred	575,000	[1]
Development costs incurred, for the period	2,834,000
Development	3,409,000
Estimated Total Cumulative Development Costs	4,300,000	[2]
Completion date (or anticipated completion date, if under construction)	11/14
Rampart IV [Member] | Lease Up [Member]
DEVELOPMENT [Abstract]
Size (Unaudited) (Square feet)	84,000
Development Costs Transferred	0	[1]
Development costs incurred, for the period	5,229,000
Development	6,947,000
Estimated Total Cumulative Development Costs	8,300,000	[2]
Completion date (or anticipated completion date, if under construction)	11/14
Alamo Ridge I [Member] | Under construction [Member]
DEVELOPMENT [Abstract]
Size (Unaudited) (Square feet)	96,000
Development Costs Transferred	1,341,000	[1]
Development costs incurred, for the period	4,134,000
Development	5,475,000
Estimated Total Cumulative Development Costs	6,700,000	[2]
Completion date (or anticipated completion date, if under construction)	01/15
Alamo Ridge II [Member] | Under construction [Member]
DEVELOPMENT [Abstract]
Size (Unaudited) (Square feet)	62,000
Development Costs Transferred	866,000	[1]
Development costs incurred, for the period	2,500,000
Development	3,366,000
Estimated Total Cumulative Development Costs	3,900,000	[2]
Completion date (or anticipated completion date, if under construction)	01/15
Steele Creek IV [Member] | Under construction [Member]
DEVELOPMENT [Abstract]
Size (Unaudited) (Square feet)	57,000
Development Costs Transferred	938,000	[1]
Development costs incurred, for the period	2,522,000
Development	3,460,000
Estimated Total Cumulative Development Costs	4,300,000	[2]
Completion date (or anticipated completion date, if under construction)	01/15
West Road III [Member] | Under construction [Member]
DEVELOPMENT [Abstract]
Size (Unaudited) (Square feet)	78,000
Development Costs Transferred	1,164,000	[1]
Development costs incurred, for the period	2,701,000
Development	3,865,000
Estimated Total Cumulative Development Costs	5,000,000	[2]
Completion date (or anticipated completion date, if under construction)	02/15
Thousand Oaks 4 [Member] | Under construction [Member]
DEVELOPMENT [Abstract]
Size (Unaudited) (Square feet)	66,000
Development Costs Transferred	1,123,000	[1]
Development costs incurred, for the period	1,820,000
Development	2,943,000
Estimated Total Cumulative Development Costs	5,100,000	[2]
Completion date (or anticipated completion date, if under construction)	03/15
Madison II & III [Member] | Under construction [Member]
DEVELOPMENT [Abstract]
Size (Unaudited) (Square feet)	127,000
Development Costs Transferred	951,000	[1]
Development costs incurred, for the period	2,729,000
Development	3,680,000
Estimated Total Cumulative Development Costs	8,000,000	[2]
Completion date (or anticipated completion date, if under construction)	04/15
Sky Harbor 6 [Member] | Under construction [Member]
DEVELOPMENT [Abstract]
Size (Unaudited) (Square feet)	31,000
Development Costs Transferred	807,000	[1]
Development costs incurred, for the period	813,000
Development	1,620,000
Estimated Total Cumulative Development Costs	3,100,000	[2]
Completion date (or anticipated completion date, if under construction)	04/15
Ten West Crossing 7 [Member] | Under construction [Member]
DEVELOPMENT [Abstract]
Size (Unaudited) (Square feet)	68,000
Development Costs Transferred	962,000	[1]
Development costs incurred, for the period	2,208,000
Development	3,170,000
Estimated Total Cumulative Development Costs	4,900,000	[2]
Completion date (or anticipated completion date, if under construction)	04/15
ParkView 1-3 [Member] | Under construction [Member]
DEVELOPMENT [Abstract]
Size (Unaudited) (Square feet)	276,000
Development Costs Transferred	3,039,000	[1]
Development costs incurred, for the period	1,037,000
Development	4,076,000
Estimated Total Cumulative Development Costs	$ 19,600,000	[2]
Completion date (or anticipated completion date, if under construction)	07/15

[1] Represents costs transferred from Prospective Development (primarily land) to Under Construction during the period.

[2] Included in these costs are development obligations of $25.3 million and tenant improvement obligations of $2.6 million on properties under development.

[3] Represents cumulative costs at the date of transfer.