DEBT (Details) (USD $)	3 Months Ended		9 Months Ended			3 Months Ended	9 Months Ended				0 Months Ended				9 Months Ended					9 Months Ended		0 Months Ended	9 Months Ended						0 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012	Sep. 30, 2013 Revolving Credit Facility [Member]	Sep. 30, 2013 Revolving Credit Facility [Member]	Sep. 20, 2012 Revolving Credit Facility [Member]	Feb. 09, 2012 Revolving Credit Facility [Member]	Sep. 30, 2013 Letter of Credit [Member]	May 23, 2013 Senior Unsecured Notes Due 2023 [Member]	May 23, 2013 Senior Unsecured Notes Due 2023 [Member] Prior to June 2018 [Member]	May 23, 2013 Senior Unsecured Notes Due 2023 [Member] Prior to June 2016 [Member]	Oct. 27, 2010 Senior Notes due 2018 [Member]	Sep. 30, 2013 Senior Notes due 2018 [Member]	Sep. 30, 2013 Senior Notes due 2018 [Member] Prior to November 2014 [Member]	Sep. 30, 2013 Senior Notes due 2018 [Member] Prior to November 2013 [Member]	Sep. 30, 2013 2013 Revolving Credit Facility [Member] Revolving Credit Facility [Member]	Jul. 29, 2013 2013 Revolving Credit Facility [Member] Revolving Credit Facility [Member]	Sep. 30, 2013 2013 Revolving Credit Facility [Member] Revolving Credit Facility [Member] Subsequent Event [Member]	Sep. 30, 2013 2013 Revolving Credit Facility [Member] Revolving Credit Facility [Member] Minimum [Member]	Jul. 29, 2013 2013 Revolving Credit Facility [Member] Revolving Credit Facility [Member] Maximum [Member]	Sep. 30, 2013 2013 Revolving Credit Facility [Member] Revolving Credit Facility [Member] Federal Funds Rate [Member]	Sep. 30, 2013 2013 Revolving Credit Facility [Member] Revolving Credit Facility [Member] London Interbank Offered Rate (LIBOR) [Member]	Sep. 30, 2013 2013 Revolving Credit Facility [Member] Revolving Credit Facility [Member] London Interbank Offered Rate (LIBOR) [Member] Minimum [Member]	Sep. 30, 2013 2013 Revolving Credit Facility [Member] Revolving Credit Facility [Member] London Interbank Offered Rate (LIBOR) [Member] Maximum [Member]	Sep. 30, 2013 2013 Revolving Credit Facility [Member] Revolving Credit Facility [Member] Base Rate [Member] Minimum [Member]	Sep. 30, 2013 2013 Revolving Credit Facility [Member] Revolving Credit Facility [Member] Base Rate [Member] Maximum [Member]	Jul. 26, 2012 Additional Senior Notes [Member]	Oct. 15, 2012 Additional Senior Notes [Member]	Sep. 30, 2013 Mortgage Indebtedness [Member]		Dec. 31, 2012 Mortgage Indebtedness [Member]
Debt Instrument [Line Items]
Principal Outstaning, Fixed Rate																															$ 85,247,000		$ 94,373,000
Weighted Average Interest Rate, Fixed Rate																															4.01%
Principal Outstaning, Variable Rate																															56,994,000	[1]	57,949,000	[1]
Weighted Average Interest Rate, Variable Rate																															5.00%	[1]
Total Principal Outstanding																															142,241,000		152,322,000
Debt Instrument, Description of Variable Rate Basis																							federal funds rate	one-month LIBOR							90-day LIBOR
Debt Instrument, Basis Spread on Variable Rate																							0.50%	1.00%							4.00%
Debt Instrument, Interest Rate, Stated Percentage Rate Range, Minimum																															1.00%
Debt Instrument, Interest Rate, Stated Percentage											5.375%			8.125%
Debt Instrument, Face Amount											200,000,000			225,000,000															100,000,000	100,000,000
Debt Instrument, Redemption Price, Principal Amount Redeemed															113,800,000
Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed															35.00%
Proceeds from Issuance of Debt											200,000,000			225,000,000															103,000,000
Proceeds from Debt, Net of Issuance Costs											194,600,000			219,900,000
Debt Instrument, Percent to Par Value																													106.00%
Debt Instrument, Interest Rate, Effective Percentage																													6.92%
Debt Instrument, Redeemable, Redemption Price of Principal Amount, Percentage												100.00%	105.375%			100.00%	108.125%
Debt Instrument, Redeemable, Principal Amount Redeemable, Percentage													35.00%
Line of Credit Facility, Maximum Borrowing Capacity						200,000,000	200,000,000		100,000,000	20,000,000									375,000,000
Line of Credit Facility, Accordion Feature, Additional Borrowing Capacity						150,000,000	150,000,000												225,000,000
Line of Credit Facility, Accordion Feature, Increased Borrowing Capacity								230,000,000
Line of Credit Facility, Optional Extension Period																		1 year
Secured revolving credit facility	0		0		92,500,000	0	0
Line of Credit Facility, Current Borrowing Capacity																		286,500,000
Proceeds from secured revolving credit facility			0	42,500,000																131,000,000
Line of Credit Facility, Interest Rate During Period																									2.50%	3.50%	1.50%	2.50%
Line of Credit Facility, Interest Rate at Period End																		3.18%
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage																					0.35%	0.50%
Interest Expense	9,739,000	9,085,000	29,884,000	24,681,000		0	800,000
Line of Credit Facility, Commitment Fee Amount						400,000	900,000
Amortization of deferred financing costs	800,000	700,000	2,395,000	1,917,000
Interest Payable	11,500,000		11,500,000		5,400,000
Gain (Loss) on extinguishment of debt	(351,000)	(453,000)	(10,101,000)	(703,000)											(9,800,000)
Gains (Losses) on Extinguishment of Debt, before Write off of Deferred Debt Issuance Cost															9,300,000
Write off of Deferred Debt Issuance Cost															$ 500,000
Debt, Weighted Average Interest Rate																															4.41%

[1] Contractual interest rates under variable rate mortgages are equal to the 90-day LIBOR plus 4.0% (subject to a 1.0% LIBOR floor).