EMPLOYEE BENEFITS (Obligation and Funded Status) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Pension Benefits [Member]
Reconciliation of benefit obligation [Roll Forward]
Benefit obligation at beginning of year	$ 131,382	[1]	$ 111,340
Service cost	6,300		5,129		3,166
Interest cost	5,175		5,049		4,761
Actuarial loss	(15,161)		12,841
Benefits payments and adjustments	(4,344)		(2,977)
Benefit obligation at end of year	123,352	[1]	131,382	[1]	111,340
Reconciliation of fair value of plan assets [Roll Forward]
Fair value of plan assets at beginning of year	75,276		65,267
Actual return on plan assets	14,287		6,236
Employer contributions	7,000		6,750
Benefits payments and adjustments	(4,344)		(2,977)
Fair value of plan assets at end of year	92,219		75,276		65,267
Funded status at end of year	(31,133)		(56,106)
Accumulated pension benefit obligation	106,207	[1]	109,229	[1]
Postretirement Benefits [Member]
Reconciliation of benefit obligation [Roll Forward]
Benefit obligation at beginning of year	44,395	[1]	36,334
Service cost	3,875		3,010		1,985
Interest cost	1,759		1,695		1,590
Actuarial loss	(1,449)		3,380
Benefits payments and adjustments	(374)		(24)
Benefit obligation at end of year	48,954	[1]	44,395	[1]	36,334
Reconciliation of fair value of plan assets [Roll Forward]
Fair value of plan assets at beginning of year	0		0
Actual return on plan assets	0		0
Employer contributions	374		24
Benefits payments and adjustments	(374)		(24)
Fair value of plan assets at end of year	0		0		0
Funded status at end of year	$ (48,954)		$ (44,395)

[1] For the pension plan, the benefit obligation is the projected benefit obligation. For the postretirement benefit plan, the benefit obligation is the accumulated postretirement benefit obligation.