DERIVATIVE INSTRUMENTS (Details) (USD $)	12 Months Ended		3 Months Ended	1 Months Ended	12 Months Ended		1 Months Ended	12 Months Ended		12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012 Designated as cash flow hedge	Dec. 31, 2011 Interest rate caps Not designated as hedging instrument	Mar. 31, 2013 Interest rate caps Not designated as hedging instrument	Sep. 30, 2011 Interest rate caps Not designated as hedging instrument	Sep. 30, 2011 Interest rate caps Not designated as hedging instrument Maximum	Mar. 31, 2013 Interest rate swap	Mar. 31, 2013 Interest rate swap Not designated as hedging instrument	Mar. 31, 2013 Interest rate swap Designated as cash flow hedge	Sep. 30, 2011 Interest rate swap Designated as cash flow hedge
Derivative instruments
Cost of interest rate cap				$ 100,000			$ 100,000
Variable interest rate base					three-Month LIBOR					three-Month LIBOR
Notional value					160,000,000	65,000,000					65,000,000
Reclassified unrealized losses to interest expense			(600,000)
Accumulated derivative loss for the interest rate swap
Unrealized losses included in accumulated other comprehensive income, at the beginning of the period								(522,000)	(541,000)	(522,000)
Unrealized losses incurred during the period	(72,000)	(327,000)						(72,000)
Reclassification of unrealized losses to realized losses	594,000							594,000
Unrealized losses included in accumulated other comprehensive income, at the end of the period									$ (541,000)