EMPLOYEE RETIREMENT PLANS (Details 2) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Change in projected benefit obligation
Service cost	$ 1,263	$ 1,726	$ 1,472
Interest cost	2,586	2,403	2,317
Change in plan assets
Fair value of plan assets, beginning of year	31,522
Fair value of plan assets, end of year	32,027	31,522
Amounts recognized in the consolidated balance sheets consist of:
Long-term pension liability	(33,379)	(21,901)
Amounts recognized in accumulated other comprehensive loss consist of:
Net amount recognized	15,136	8,488
Defined Benefit Pension Plan [Member]
Change in projected benefit obligation
Projected benefit obligation, beginning of year	41,470	43,452
Service cost	1,042	1,406
Interest cost	1,999	1,832
Actuarial loss (gain)	8,221	(3,466)
Benefits paid	(1,800)	(1,754)
Projected benefit obligation, end of year	50,932	41,470
Change in plan assets
Fair value of plan assets, beginning of year	31,522	27,819
Actual return on plan assets	1,145	4,316
Administrative expenses	(140)	(141)
Contributions	1,300	1,282
Benefits paid	(1,800)	(1,754)
Fair value of plan assets, end of year	32,027	31,522
Funded status of plan	(18,905)	(9,948)
Amounts recognized in the consolidated balance sheets consist of:
Accrued liabilities - other	0	0
Long-term pension liability	(18,905)	(9,948)
Net amount recognized	(18,905)	(9,948)
Amounts recognized in accumulated other comprehensive loss consist of:
Accumulated loss, net of income tax benefit of $7,559, $4,054, $2,431 and $1,729, respectively	11,824	6,341
Prior service cost (credit), net of income tax benefit (liability) of $0, $1, (314) and ($358), respectively	0	1
Net amount recognized	11,824	6,342
Supplemental Pension Plan [Member]
Change in projected benefit obligation
Projected benefit obligation, beginning of year	12,337	12,270
Service cost	221	320
Interest cost	586	570
Actuarial loss (gain)	2,047	(468)
Benefits paid	(350)	(355)
Projected benefit obligation, end of year	14,841	12,337
Change in plan assets
Fair value of plan assets, beginning of year	0	0
Actual return on plan assets	0	0
Administrative expenses	0	0
Contributions	350	355
Benefits paid	(350)	(355)
Fair value of plan assets, end of year	0	0
Funded status of plan	(14,841)	(12,337)
Amounts recognized in the consolidated balance sheets consist of:
Accrued liabilities - other	(367)	(384)
Long-term pension liability	(14,474)	(11,953)
Net amount recognized	(14,841)	(12,337)
Amounts recognized in accumulated other comprehensive loss consist of:
Accumulated loss, net of income tax benefit of $7,559, $4,054, $2,431 and $1,729, respectively	3,803	2,705
Prior service cost (credit), net of income tax benefit (liability) of $0, $1, (314) and ($358), respectively	(491)	(559)
Net amount recognized	$ 3,312	$ 2,146