EMPLOYEE BENEFIT PLANS (Details 2) (PLC, USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Pension Plan
EMPLOYEE BENEFIT PLANS
Accumulated benefit obligation, end of year	$ 249,453	$ 207,999
Change in projected benefit obligation:
Projected benefit obligation at beginning of year	219,152	223,319
Service cost - benefits earned during the period	9,411	9,345	9,145
Interest cost on projected benefit obligation	10,493	8,985	8,977
Actuarial (gain) or loss	38,110	(8,172)
Benefits paid	(9,835)	(14,325)
Projected benefit obligation at end of year	267,331	219,152	223,319
Change in plan assets:
Fair value of plan assets at beginning of year	180,173	152,187
Actual return on plan assets	17,921	33,368
Employer contributions	15,513	8,943
Benefits paid	(9,835)	(14,325)
Fair value of plan assets at end of year	203,772	180,173	152,187
After reflecting FASB guidance:
Funded status	(63,559)	(38,979)
Amounts recognized in the balance sheet:
Other liabilities	(63,559)	(38,979)
Amounts recognized in accumulated other comprehensive income:
Net actuarial loss	80,430	54,897
Prior service cost/(credit)	(1,033)	(1,425)
Net transition asset	79,397	53,472
Unfunded Excess Benefits Plan
EMPLOYEE BENEFIT PLANS
Accumulated benefit obligation, end of year	47,368	36,306
Change in projected benefit obligation:
Projected benefit obligation at beginning of year	39,679	42,971
Service cost - benefits earned during the period	954	1,037	867
Interest cost on projected benefit obligation	1,696	1,387	1,473
Actuarial (gain) or loss	9,153	(1,505)
Benefits paid	(1,907)	(4,211)
Projected benefit obligation at end of year	49,575	39,679	42,971
Change in plan assets:
Employer contributions	1,907	4,211
Benefits paid	(1,907)	(4,211)
After reflecting FASB guidance:
Funded status	(49,575)	(39,679)
Amounts recognized in the balance sheet:
Other liabilities	(49,575)	(39,679)
Amounts recognized in accumulated other comprehensive income:
Net actuarial loss	20,983	13,346
Prior service cost/(credit)	24	36
Net transition asset	21,007	13,382
Retiree medical plan
Change in projected benefit obligation:
Projected benefit obligation at beginning of year	447	788
Service cost - benefits earned during the period	2	4
Interest cost on projected benefit obligation	4	5
Actuarial (gain) or loss	30	29
Plan participant contributions	254	289
Benefits paid	(490)	(668)
Projected benefit obligation at end of year	247	447
Change in plan assets:
Benefits paid	(490)	(668)
Group life insurance plan
Change in projected benefit obligation:
Projected benefit obligation at beginning of year	8,653	10,070
Service cost - benefits earned during the period	97	144
Interest cost on projected benefit obligation	416	405
Actuarial (gain) or loss	694	(1,620)
Benefits paid	(572)	(346)
Projected benefit obligation at end of year	9,288	8,653
Change in plan assets:
Benefits paid	$ (572)	$ (346)