LINES OF CREDIT (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011
Line of Credit
Amount Drawn	$ 215,000
Capacity	336,000
Credit Line 1
Line of Credit
Amount Drawn	100,000
Capacity	100,000
Interest Rate (as a percent)	1.30%
Line of credit facility variable rate basis	LIBOR
Credit Line 1 | Minimum
Line of Credit
Basis spread on variable rate (as a percent)	1.00%
Credit Line 1 | Maximum
Line of Credit
Basis spread on variable rate (as a percent)	2.10%
Credit Line 2
Line of Credit
Amount Drawn	40,000
Capacity	74,000
Interest Rate (as a percent)	2.40%
Line of credit facility variable rate basis	LIBOR
Basis spread on variable rate (as a percent)	2.15%
Extension of maturity date (in years)	1
Credit Line 3
Line of Credit
Amount Drawn	40,000
Capacity	72,000
Interest Rate (as a percent)	2.50%
Line of credit facility variable rate basis	LIBOR
Basis spread on variable rate (as a percent)	2.20%
Extension of maturity date (in years)	2
Number of extensions to maturity date (in count)	1
Credit Line 4
Line of Credit
Amount Drawn	25,000
Capacity	40,000
Interest Rate (as a percent)	2.50%
Line of credit facility variable rate basis	LIBOR
Basis spread on variable rate (as a percent)	2.20%
Extension of maturity date (in years)	1
Number of extensions to maturity date (in count)	2
Credit Line 5
Line of Credit
Amount Drawn	10,000
Capacity	$ 50,000
Interest Rate (as a percent)	2.40%
Line of credit facility variable rate basis	LIBOR
Basis spread on variable rate (as a percent)	2.15%
Extension of maturity date (in years)	1
Number of extensions to maturity date (in count)	2