FAIR VALUE MEASUREMENTS (Details 2) (Level 2, USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Carrying Value
Fair Value And Carrying Value By Balance Sheet Grouping [Line Items]
Total debt	$ 2,645,630	$ 2,941,444
Carrying Value | Fixed Rate Debt
Fair Value And Carrying Value By Balance Sheet Grouping [Line Items]
Total debt	2,569,630	2,070,244
Carrying Value | Variable Rate Debt
Fair Value And Carrying Value By Balance Sheet Grouping [Line Items]
Total debt	76,000	871,200
Fair Value
Fair Value And Carrying Value By Balance Sheet Grouping [Line Items]
Total debt	2,760,646	3,074,862
Fair Value | Fixed Rate Debt
Fair Value And Carrying Value By Balance Sheet Grouping [Line Items]
Total debt	2,684,646	2,203,662
Fair Value | Variable Rate Debt
Fair Value And Carrying Value By Balance Sheet Grouping [Line Items]
Total debt	$ 76,000	$ 871,200