EMPLOYEE BENEFIT PLANS (Details 2) (PLC, USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Defined Benefit Pension Plan
EMPLOYEE BENEFIT PLANS
Accumulated benefit obligation, end of year	$ 210,319	$ 186,300
Change in projected benefit obligation:
Projected benefit obligation at beginning of year	199,162	165,704
Service cost	9,145	8,682	7,423
Interest cost	8,977	8,938	8,091
Amendments		94
Actuarial (gain) or loss	15,286	23,859
Benefits paid	(9,251)	(8,115)
Projected benefit obligation at end of year	223,319	199,162	165,704
Change in plan assets:
Fair value of plan assets at beginning of year	125,058	117,856
Actual return on plan assets	15,202	2,874
Employer contributions	21,178	12,443
Benefits paid	(9,251)	(8,115)
Fair value of plan assets at end of year	152,187	125,058	117,856
After reflecting FASB guidance:
Funded status	(71,132)	(74,104)
Amounts recognized in the balance sheet:
Other liabilities	(71,132)	(74,104)
Amounts recognized in accumulated other comprehensive income:
Net actuarial loss	95,055	91,804
Prior service cost/(credit)	(1,816)	(2,208)
Net transition asset	93,239	89,596
Unfunded Excess Benefits Plan
EMPLOYEE BENEFIT PLANS
Accumulated benefit obligation, end of year	39,828	33,675
Change in projected benefit obligation:
Projected benefit obligation at beginning of year	36,256	31,592
Service cost	867	679	584
Interest cost	1,473	1,506	1,545
Amendments		3
Actuarial (gain) or loss	6,946	4,187
Benefits paid	(2,571)	(1,711)
Projected benefit obligation at end of year	42,971	36,256	31,592
Change in plan assets:
Employer contributions	2,571	1,711
Benefits paid	(2,571)	(1,711)
After reflecting FASB guidance:
Funded status	(42,971)	(36,256)
Amounts recognized in the balance sheet:
Other liabilities	(42,971)	(36,256)
Amounts recognized in accumulated other comprehensive income:
Net actuarial loss	17,571	11,924
Prior service cost/(credit)	48	60
Net transition asset	17,619	11,984
Other Postretirement Benefits
EMPLOYEE BENEFIT PLANS
Accumulated benefit obligation, end of year	800	900
Retiree medical plan
Change in projected benefit obligation:
Projected benefit obligation at beginning of year	949	1,309
Service cost	6	9
Interest cost	17	28
Amendments		(29)
Actuarial (gain) or loss	(144)	(297)
Benefits paid	(333)	(326)
Plan participant contributions	293	255
Projected benefit obligation at end of year	788	949
Change in plan assets:
Benefits paid	(333)	(326)
Group life insurance plan
Change in projected benefit obligation:
Projected benefit obligation at beginning of year	8,951	7,955
Service cost	123	118
Interest cost	412	416
Actuarial (gain) or loss	895	816
Benefits paid	(311)	(354)
Projected benefit obligation at end of year	10,070	8,951
Change in plan assets:
Benefits paid	$ (311)	$ (354)