RETIREMENT PLANS: (Details 1) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Change in benefit obligation:
Benefit obligation at January 1	$ 81,469	$ 86,807
Service cost	2,040us-gaap_DefinedBenefitPlanServiceCost	2,238us-gaap_DefinedBenefitPlanServiceCost	4,872us-gaap_DefinedBenefitPlanServiceCost
Interest cost	3,756us-gaap_DefinedBenefitPlanInterestCost	3,383us-gaap_DefinedBenefitPlanInterestCost	3,667us-gaap_DefinedBenefitPlanInterestCost
Actuarial (gain) loss	22,274	(7,098)
Benefits paid	(4,256)us-gaap_DefinedBenefitPlanBenefitsPaid	(3,861)us-gaap_DefinedBenefitPlanBenefitsPaid
Benefit obligation at December 31	98,135	81,469	86,807
Reconciliation of fair value of plan assets:
Fair value of plan assets at January 1	67,233	57,491
Actual return on plan assets	2,957	10,909
Employer contributions	3,779	2,694
Benefits paid	(4,256)us-gaap_DefinedBenefitPlanBenefitsPaid	(3,861)us-gaap_DefinedBenefitPlanBenefitsPaid
Fair value of plan assets at December 31	62,565	67,233	57,491
Funded status at December 31 (plan assets less benefit obligation)	(35,570)	(14,236)
Defined Benefit Plan, Settlements, Benefit Obligation	(7,148)
Defined Benefit Plan, Settlements, Plan Assets	$ (7,148)

The difference between fair value of plan assets at the end of the period and the fair value at the beginning of the period, adjusted for contributions and payments of benefits during the period, and after adjusting for taxes and other expenses, as applicable.

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Amount of gain (loss) related to change in benefit obligation resulting from changes in actuarial assumptions, for example, but not limited to, interest, mortality, employee turnover, salary, and temporary deviation from the substantive plan.

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1) For defined benefit pension plans, the benefit obligation is the projected benefit obligation, which is the actuarial present value as of a date of all benefits attributed by the pension benefit formula to employee service rendered prior to that date. 2) For other postretirement defined benefit plans, the benefit obligation is the accumulated postretirement benefit obligation, which is the actuarial present value of benefits attributed to employee service rendered to a particular date.

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The amount of payments made for which participants are entitled under a pension plan, including pension benefits, death benefits, and benefits due on termination of employment. Also includes payments made under a postretirement benefit plan, including prescription drug benefits, health care benefits, life insurance benefits, and legal, educational and advisory services. This item represents a periodic decrease to the plan obligations and a decrease to plan assets.

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The increase in the fair value of plan assets from contributions made by the employer.

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Assets, usually stocks, bonds, and other investments, that have been segregated and restricted (usually in a trust) to provide benefits, at their fair value as of the measurement date. Plan assets include amounts contributed by the employer (and by employees for a contributory plan) and amounts earned from investing the contributions, less benefits paid. If a plan has liabilities other than for benefits, those non-benefit obligations may be considered as reductions of plan assets.

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The funded status is measured as the difference between the fair value of plan assets and the benefit obligation. Will normally be the same as the net Defined Benefit Plan, Amounts Recognized in Balance Sheet, Total.

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The increase in a defined benefit pension plan's projected benefit obligation or a defined benefit postretirement plan's accumulated postretirement benefit obligation due to the passage of time.

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The actuarial present value of benefits attributed by the pension benefit formula to services rendered by employees during the period. The portion of the expected postretirement benefit obligation attributed to employee service during the period. The service cost component is a portion of the benefit obligation and is unaffected by the funded status of the plan.

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The amount of decrease that relates to an irrevocable action that relieves the employer (or the plan) of primary responsibility for a benefit obligation and eliminates significant risks related to the obligation and the assets used to effect the settlement. Examples of transactions that constitute a settlement include (a) making lump-sum cash payments to plan participants in exchange for their rights to receive specified benefits and (b) purchasing nonparticipating annuity contracts.

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