EMPLOYEE BENEFIT PLANS: (Tables)

12 Months Ended

Dec. 31, 2015

EMPLOYEE BENEFIT PLANS:

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

Prior service credit	$	(8,098)
Net actuarial gain		(2,371)
Net amount recognized in accumulated other comprehensive loss	$	(10,469)

Schedule of changes in accumulated postretirement benefit obligation

	December 31,
	2015		2014
Benefit obligation, beginning of year	$	12,311	$	9,176
Service cost		441		342
Interest cost		465		423
Actuarial (gain)/loss		(1,580)		2,611
Benefits paid		(237)		(241)
Benefit obligation, end of year	$	11,400	$	12,311

Schedule of net periodic postretirement benefit cost

	2015		2014		2013
Service cost—benefits attributed to service during the period	$	441	$	342	$	1,036
Interest cost on the accumulated postretirement benefit obligation		465		423		1,060
Net amortization		(1,451)		(1,804)		671
Net periodic postretirement benefit cost (income)	$	(545)	$	(1,039)	$	2,767