DERIVATIVE FINANCIAL INSTRUMENTS (Details) (USD $)	Mar. 31, 2013 Transaction	Dec. 31, 2012
Derivatives, Fair Value [Line Items]
Number of Forward Starting Interest Rate Swap Transactions	2
Accumulated other comprehensive income - unrealized loss on valuation of swap agreements	$ 4,900,000	$ 4,300,000
Level 2
Derivatives, Fair Value [Line Items]
Derivative financial instruments	5,000,000	4,400,000
Fair Value, Measurements, Recurring | Level 2
Derivatives, Fair Value [Line Items]
Derivative financial instruments	5,044,000
Cash Flow Hedging | Variable-Rate Derivatives, Maturing in October 2012
Derivatives, Fair Value [Line Items]
Derivative, Cap Interest Rate	3.00%
Cash Flow Hedging | Variable Rate Derivatives Maturing in July 2015 [Member]
Derivatives, Fair Value [Line Items]
Derivative, Cap Interest Rate	4.30%
Interest Rate Swap | Cash Flow Hedging | Fixed-Rate Derivatives, Maturing between November 2012 and December 2022
Derivatives, Fair Value [Line Items]
Number of interest rate swaps (in interest rate swaps)	8
Notional Amount of Interest Rate Cash Flow Hedge Derivatives	148,600,000
Interest Rate Swap | Cash Flow Hedging | Fixed-Rate Derivatives, Maturing between November 2012 and December 2022 | Minimum
Derivatives, Fair Value [Line Items]
Derivative, Fixed Interest Rate	0.52%
Interest Rate Swap | Cash Flow Hedging | Fixed-Rate Derivatives, Maturing between November 2012 and December 2022 | Maximum
Derivatives, Fair Value [Line Items]
Derivative, Fixed Interest Rate	3.77%
Interest Rate Swap | Cash Flow Hedging | Variable-Rate Derivatives
Derivatives, Fair Value [Line Items]
Notional Amount of Interest Rate Cash Flow Hedge Derivatives	182,900,000
Derivative, Number of Instruments Held	6
Forward Contracts | Cash Flow Hedging | Variable-Rate Derivatives
Derivatives, Fair Value [Line Items]
Notional Amount of Interest Rate Cash Flow Hedge Derivatives	$ 25,000,000