EMPLOYEE BENEFIT PLANS (Details 4) (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
Service cost - benefits earned during the period	$ 9,145	$ 8,682	$ 7,423
Interest cost on projected benefit obligation	8,977	8,938	8,091
Expected return on plan assets	(10,916)	(10,021)	(9,349)
Amortization of prior service cost/(credit)	(392)	(392)	(403)
Amortization of actuarial losses	7,749	5,625	3,905
Total benefit cost	14,563	12,832	9,667
Average remaining service period used	8 years 1 month 20 days
Estimated net actuarial loss, prior service cost, and transition obligation for these plans that will be amortized from accumulated other comprehensive income into net periodic benefit cost during 2013
Net actuarial loss	9,150
Prior service cost/(credit)	(392)
Unfunded Excess Benefits Plan
EMPLOYEE BENEFIT PLANS
Service cost - benefits earned during the period	867	679	584
Interest cost on projected benefit obligation	1,473	1,506	1,545
Amortization of prior service cost/(credit)	12	12	12
Amortization of actuarial losses	1,300	881	653
Total benefit cost	3,652	3,078	2,794
Average remaining service period used	7 years 6 months 4 days
Estimated net actuarial loss, prior service cost, and transition obligation for these plans that will be amortized from accumulated other comprehensive income into net periodic benefit cost during 2013
Net actuarial loss	1,767
Prior service cost/(credit)	$ 12