RETIREMENT PLANS: (Details 1) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Change in benefit obligation:
Benefit obligation at January 1	$ 98,135	$ 81,469
Service cost	2,153	2,040	$ 2,238
Interest cost	3,516	3,756	3,383
Actuarial (gain) loss	(8,802)	22,274
Benefits paid	(4,147)	(4,256)
Benefit obligation at December 31	90,855	98,135	81,469
Reconciliation of fair value of plan assets:
Fair value of plan assets at January 1	62,565	67,233
Actual return on plan assets	(205)	2,957
Employer contributions	2,389	3,779
Benefits paid	(4,147)	(4,256)
Fair value of plan assets at December 31	60,602	62,565	$ 67,233
Funded status at December 31 (plan assets less benefit obligation)	(30,253)	(35,570)
Defined Benefit Plan, Settlements, Benefit Obligation	0	(7,148)
Defined Benefit Plan, Settlements, Plan Assets	$ 0	$ (7,148)