RETIREMENT PLANS: (Details 7) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net loss (gain) during the period	$ (5,883)	$ 3,188	$ 6,362
Amortization of prior service cost	(1)	(1)	(1)
Amortization of unrecognized (gain) loss	(2,072)	(1,967)	(1,558)
Total recognized in other comprehensive income (loss)	(7,956)	1,220	4,803
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	54	1,459	1,357
Amortization of prior service cost	0	0	0
Amortization of unrecognized (gain) loss	(441)	(246)	(75)
Total recognized in other comprehensive income (loss)	$ (387)	$ 1,213	$ 1,282