SHARE-BASED PAYMENTS (Details) (USD $) In Thousands, except Share data, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2011	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Executives [Abstract]
Stock based compensation expense		$ 7,590	$ 6,649	$ 2,143
2011 Annual LTIP [Member]
Executives [Abstract]
Terms of Share-based payment awards		Shares are earned under the 2011 Annual LTIP based on achieving a threshold, target or maximum level of performance in certain defined areas of performance. The Company accounts for these grants as performance awards for which the Company assesses the probable achievement of the performance conditions at the end of each period. Any common shares issued in settlement of equity awards under the 2011 Annual LTIP will be made pursuant to the 2012 Plan.
Stock based compensation expense		1,476
Corresponding liability included in accounts payable		1,476
2010 Annual LTIP [Member]
Executives [Abstract]
Terms of Share-based payment awards		pursuant to the 2010 Annual LTIP of which 25 percent vested immediately and the remaining will vest 25 percent on December 31, 2011, 25 percent on December 31, 2012, and 25 percent on December 31, 2013.	This program has a three-year performance period, which commenced on January 1, 2010 and will end on December 31, 2012. The common shares to be issued in settlement of equity awards granted under this program are based upon the Company's achievement of a certain level of 1 absolute total shareholder return 75 percent of the award, and 2 relative total shareholder return as compared to the Company's peer group 25 percent of the award.
Stock based compensation expense		703	1,314
Corresponding liability included in accounts payable			1,314
Shares issued (in shares)		440,669
Unvested Share Awards [Abstract]
Unearned Compensation		605
Unearned Compensation		605
Percentage of Shares issued pursuant to the 2010 Annual LTIP which vested immediately (in hundredths)			25.00%
Percentage of Shares issued pursuant to the 2010 Annual LTIP which vest in 2011 (in hundredths)			25.00%
Percentage of Shares issued pursuant to the 2010 Annual LTIP which vest in 2012 (in hundredths)			25.00%
Percentage of Shares issued pursuant to the 2010 Annual LTIP which vest in 2013 (in hundredths)			25.00%
Grant date fair value of the shares awarded (in dollars per share)			$ 5.98
Multi-Year Long-Term Equity Incentive [Member]
Executives [Abstract]
Stock based compensation expense		3,192	2,084
Unvested Share Awards [Abstract]
Unearned Compensation		6,383	9,575
Unearned Compensation		6,383	9,575
Performance Share Awards [Member]
Executives [Abstract]
Stock based compensation expense			725	140
Restricted Share Awards [Member]
Executives [Abstract]
Stock based compensation expense		1,662	2,230	1,899
Unvested Share Awards [Abstract]
Shares Issued (in shares)	22,800	1,440,385
Share Price on date of grant (in dollars per share)	$ 5.83
Shares Vested (in shares)		889,720	531,294
Unearned Compensation		1,370	2,940
Unearned Compensation		1,370	2,940
Shares Vested (in shares)		889,720	531,294
Restricted Share Awards [Member] | Issued 06-01-2007 [Member]
Unvested Share Awards [Abstract]
Shares Issued (in shares)		214,582
Share Price on date of grant (in dollars per share)		$ 12.32	$ 12.32
Vesting Period, minimum (in years)		4Y
Vesting Schedule, minimum (in hundredths)		25.00%
Shares Vested (in shares)		214,582	160,933
Unearned Compensation		0	275
Unearned Compensation		0	275
Vesting Period (in years)		4Y
Vesting Schedule (in hundredths)		25.00%
Shares Vested (in shares)		214,582	160,933
Restricted Share Awards [Member] | Issued 06-02-2008 [Member]
Unvested Share Awards [Abstract]
Shares Issued (in shares)		278,059
Share Price on date of grant (in dollars per share)		$ 8.97	$ 8.97
Vesting Period, minimum (in years)		4Y
Vesting Schedule, minimum (in hundredths)		25.00%
Shares Vested (in shares)		208,542	139,028
Unearned Compensation		260	883
Unearned Compensation		260	883
Vesting Period (in years)		4Y
Vesting Schedule (in hundredths)		25.00%
Shares Vested (in shares)		208,542	139,028
Restricted Share Awards [Member] | Issued 09-30-2008 [Member]
Unvested Share Awards [Abstract]
Shares Issued (in shares)		3,616
Share Price on date of grant (in dollars per share)		$ 7.44	$ 7.44
Vesting Period, minimum (in years)		1Y
Vesting Period, maximum (in years)		4Y
Vesting Schedule, minimum (in hundredths)		25.00%
Vesting Schedule, maximum (in hundredths)		100.00%
Shares Vested (in shares)		2,962	2,308
Unearned Compensation		4	9
Unearned Compensation		4	9
Vesting Period (in years)		1Y
Vesting Schedule (in hundredths)		25.00%
Shares Vested (in shares)		2,962	2,308
Restricted Share Awards [Member] | Issued 06-01-2009 [Member]
Unvested Share Awards [Abstract]
Shares Issued (in shares)		744,128
Share Price on date of grant (in dollars per share)		$ 2.80	$ 2.80
Vesting Period, minimum (in years)		4Y
Vesting Schedule, minimum (in hundredths)		25.00%
Shares Vested (in shares)		372,483	186,241
Unearned Compensation		737	1,258
Unearned Compensation		737	1,258
Vesting Period (in years)		4Y
Vesting Schedule (in hundredths)		25.00%
Shares Vested (in shares)		372,483	186,241
Restricted Share Awards [Member] | Issued 06-01-2010 [Member]
Unvested Share Awards [Abstract]
Shares Issued (in shares)		182,308
Share Price on date of grant (in dollars per share)		$ 4.63	$ 4.63
Vesting Period, minimum (in years)		2Y
Vesting Period, maximum (in years)		3Y
Vesting Schedule, minimum (in hundredths)		25.00%
Vesting Schedule, maximum (in hundredths)		50.00%
Shares Vested (in shares)		91,151	42,784
Unearned Compensation		291	515
Unearned Compensation		291	515
Vesting Period (in years)		2Y
Vesting Schedule (in hundredths)		25.00%
Shares Vested (in shares)		91,151	42,784
Restricted Share Awards [Member] | Issued 06-30-2011 [Member]
Unvested Share Awards [Abstract]
Shares Issued (in shares)		17,692
Share Price on date of grant (in dollars per share)		$ 5.57	$ 5.57
Vesting Period, minimum (in years)		2Y
Vesting Period, maximum (in years)		4Y
Vesting Schedule, minimum (in hundredths)		25.00%
Vesting Schedule, maximum (in hundredths)		50.00%
Shares Vested (in shares)		0	0
Unearned Compensation		78	0
Unearned Compensation		78	0
Vesting Period (in years)		2Y
Vesting Schedule (in hundredths)		25.00%
Shares Vested (in shares)		0	0
Trustees [Member]
Executives [Abstract]
Stock based compensation expense		322	264	104
Shares issued (in shares)		12,600
Unvested Share Awards [Abstract]
Shares Issued (in shares)		38,782
Share Price on date of grant (in dollars per share)		$ 4.88
Unearned Compensation		43
Unearned Compensation		43
Trustees [Member] | Annual Retainer [Member]
Executives [Abstract]
Stock based compensation expense		111
Reduction of compensation expense from forfeitures		33
Unvested Share Awards [Abstract]
Percentage premium on retainer equity option (in hundredths)		25.00%
Non-employees [Member]
Executives [Abstract]
Stock based compensation expense		104	32
Unvested Share Awards [Abstract]
Shares Vested (in shares)		11,705	0
Unearned Compensation		70	20
Unearned Compensation		70	20
Shares Issued (in shares)		23,035
Share Price on date of grant (in dollars per share)		$ 6.60
Shares Vested (in shares)		11,705	0
Non-employees [Member] | Issued 01-06-2011 [Member]
Unvested Share Awards [Abstract]
Vesting Period, minimum (in years)		1.5Y
Vesting Schedule, minimum (in hundredths)		50.00%
Shares Vested (in shares)		8,705	0
Unearned Compensation		55	0
Unearned Compensation		55	0
Shares Issued (in shares)		17,035
Share Price on date of grant (in dollars per share)		$ 6.66
Vesting Period (in years)		1.5Y
Vesting Schedule (in hundredths)		50.00%
Shares Vested (in shares)		8,705	0
Non-employees [Member] | Issued 03-25-2010 [Member]
Unvested Share Awards [Abstract]
Vesting Period, minimum (in years)		2Y
Vesting Schedule, minimum (in hundredths)		50.00%
Shares Vested (in shares)		3,000	0
Unearned Compensation		15	20
Unearned Compensation		$ 15	$ 20
Shares Issued (in shares)		6,000
Share Price on date of grant (in dollars per share)		$ 5.02
Vesting Period (in years)		2Y
Vesting Schedule (in hundredths)		50.00%
Shares Vested (in shares)		3,000	0
Non-management Trustee [Member]
Executives [Abstract]
Shares issued (in shares)		1,800