EMPLOYEE BENEFIT PLANS: (Tables)

12 Months Ended

Dec. 31, 2014

Pension Plans

Schedule of amounts recognized in accumulated other comprehensive loss (pre-tax)

Prior service credit	$	(9,449)
Net actuarial loss		(892)
Net amount recognized in accumulated other comprehensive (gain) loss	$	(10,341)

Schedule of changes in accumulated postretirement benefit obligation

	December 31,
	2014		2013
Benefit obligation, beginning of year	$	9,176	$	27,381
Service cost		342		1,036
Interest cost		423		1,060
Plan amendments		—		(10,425)
Actuarial (gain)/loss		2,611		(9,734)
Benefits paid		(241)		(142)
Benefit obligation, end of year	$	12,311	$	9,176

Schedule of net periodic postretirement benefit cost

	2014		2013		2012
Service cost—benefits attributed to service during the period	$	342	$	1,036	$	1,034
Interest cost on the accumulated postretirement benefit obligation		423		1,060		1,113
Net amortization		(1,804)		671		1,036
Net periodic postretirement benefit cost (income)	$	(1,039)	$	2,767	$	3,183