RETIREMENT PLANS: (Details 7) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net loss (gain) during the period	$ (14,697)	$ 3,842	$ 17,868
Amortization of prior service cost	16	(166)	(166)
Amortization of unrecognized gain (loss)	(2,091)	(2,270)	(986)
Total recognized in other comprehensive income (loss)	(16,772)	(4,294)	16,716
Supplemental Employee Retirement Plans, Defined Benefit
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net loss (gain) during the period	(333)	442	486
Amortization of prior service cost	0	0	(74)
Amortization of unrecognized gain (loss)	(68)	(79)	39
Total recognized in other comprehensive income (loss)	$ (401)	$ 363	$ 451