RETIREMENT PLANS: (Details 5) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 67,233	$ 57,491	$ 53,935
Quoted Prices in Active Markets for Identical Assets - Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	55,218	46,894
Significant Other Observable Inputs - Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	12,015	10,597
Significant Observable Inputs - Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	53,112	43,393
Equity Securities | Quoted Prices in Active Markets for Identical Assets - Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	53,112	43,393
Equity Securities | Significant Other Observable Inputs - Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Equity Securities | Significant Observable Inputs - Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	12,015	10,597
Debt securities | Quoted Prices in Active Markets for Identical Assets - Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt securities | Significant Other Observable Inputs - Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	12,015	10,597
Debt securities | Significant Observable Inputs - Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Investment Funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2,106	3,501
Investment Funds | Quoted Prices in Active Markets for Identical Assets - Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2,106	3,501
Investment Funds | Significant Other Observable Inputs - Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Investment Funds | Significant Observable Inputs - Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 0	$ 0