EMPLOYEE BENEFIT PLANS Table 1 (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Sep. 30, 2016	Dec. 31, 2015
Amounts recognized in the consolidated balance sheet: (a)
Net pension liability			$ 0
Pension Plans (The Pension Plan, Excess Pension Plan and SERP) [Member]
Change in benefit obligation:
Benefit obligation, January 1	$ 106,848,000
Service cost	7,676,000	$ 8,049,000
Interest cost	4,389,000	4,225,000
Benefits paid	(4,338,000)
Participant contributions	0
Actuarial gain	(5,373,000)
Benefit obligation, December 31	109,202,000	106,848,000
Change in plan assets:
Plan assets at fair value, January 1	83,365,000
Actual return on plan assets	645,000
Company contributions	8,034,000
Benefits paid	(4,338,000)
Participant contributions	0
Plan assets at fair value, December 31	87,706,000	83,365,000
Reconciliation of funded status:
Fair value of plan assets at December 31	83,365,000	83,365,000		$ 87,706,000
Less: Benefit obligation at December 31	106,848,000	106,848,000		109,202,000
Funded status at December 31				(21,496,000)
Amounts recognized in the consolidated balance sheet: (a)
Accrued compensation expense				(71,000)
Long-term liabilities				(21,425,000)
Net pension liability				(21,496,000)
Other Postretirement Benefit Plans [Member]
Change in benefit obligation:
Benefit obligation, January 1	10,484,000
Service cost	470,000	374,000
Interest cost	448,000	373,000
Benefits paid	(507,000)
Participant contributions	203,000
Actuarial gain	(1,056,000)
Benefit obligation, December 31	10,042,000	10,484,000
Change in plan assets:
Plan assets at fair value, January 1	0
Actual return on plan assets	0
Company contributions	304,000
Benefits paid	(507,000)
Participant contributions	203,000
Plan assets at fair value, December 31	0	0
Reconciliation of funded status:
Fair value of plan assets at December 31	0	0		0
Less: Benefit obligation at December 31	$ 10,484,000	$ 10,484,000		10,042,000
Funded status at December 31				(10,042,000)
Amounts recognized in the consolidated balance sheet: (a)
Accrued compensation expense				(304,000)
Long-term liabilities				(9,738,000)
Net pension liability				$ (10,042,000)