EMPLOYEE BENEFIT PLANS: (Tables)

12 Months Ended

Dec. 31, 2011

EMPLOYEE BENEFIT PLANS:

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

Prior service credit	$	(626	)
Net actuarial loss	8,255
Net amount recognized in accumulated other comprehensive loss	$	7,629

Schedule of changes in accumulated postretirement benefit obligation

	December 31
	2011			2010
Benefit obligation, beginning of year	$	20,689		$	16,674
Service cost	831			696
Interest cost	1,117			958
Actuarial loss	3,898			2,714
Benefits paid	(427		)	(353		)
Benefit obligation, end of year	$	26,108		$	20,689

Schedule of net periodic postretirement benefit cost

	2011		2010		2009
Service cost—benefits attributed to service during the period	$	831	$	696	$	704
Interest cost on the accumulated postretirement benefit obligation	1,117		958		853
Net amortization	501		128		140
Net periodic postretirement benefit cost	$	2,449	$	1,782	$	1,697

Schedule of increasing or decreasing health care trend rates by one percentage point

	1% Increase		1% Decrease
Postretirement benefit obligation	$	6,247	$	(4,277	)
Total of service and interest cost components	$	484	$	(320	)