DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES: (Details 1) (Cash Flow Hedging [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Interest Rate Swap [Member]
Derivative Instruments, Amount of Gain in Other Comprehensive Loss on Derivative (Effective Portion)	$ 0	$ 1,426	$ 662
Interest Expense [Member]
Derivative Instruments, Loss Reclassified from Accumulated Other Comprehensive Loss into Income (Effective Portion)	0	(258)	(1,510)
Derivative Instruments, Gain (Loss) in Income (Ineffective Portion and Amount Excluded from Effectiveness Testing)	$ 0	$ 0	$ 0