RETIREMENT PLANS (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Pension Benefit
Retirement plans
Employment period or credited service period for which participants' average salary or hourly wages is used as a base to calculate benefits	3 years
Weighted-average rates assumed in the actuarial calculations for the pension plan
Discount rate (as a percent)				4.30%	5.80%	5.80%
Annual salary increase (as a percent)				6.50%	6.50%	6.50%
Expected long-term return on plan assets (as a percent)	6.30%	6.50%	7.00%
Projected benefit obligations:
Balance at beginning of year	$ 14,400,000	$ 14,093,000
Innovative acquisition	69,178,000
Service cost	1,308,000	652,000	$ 612,000
Interest cost	2,002,000	766,000	720,000
Curtailment	128,000
Benefits and settlements paid	(6,445,000)	(1,329,000)
Actuarial (gain) loss	(4,437,000)	218,000
Experience Loss	(15,000)
Balance at end of year	76,119,000	14,400,000	14,093,000
Plan net assets:
Balance at beginning of year	11,946,000	13,165,000
Innovative acquisition	45,116,000
Actual return on plan assets	1,717,000	110,000
Company contributions	22,963,000
Benefits and settlements paid	(6,411,000)	(1,329,000)
Balance at end of year	75,331,000	11,946,000	13,165,000
Funded status of plan
Projected benefit obligation	14,400,000	14,093,000	14,093,000	$ 76,119,000	$ 14,400,000	$ 14,093,000
Under funded status of plan				(788,000)	(2,454,000)
Pension plan assets
Fair value of plan assets	11,946,000	13,165,000	13,165,000	$ 75,331,000	$ 11,946,000	$ 13,165,000
Weighted-average asset allocations (as a percent)				100.00%	100.00%
Amounts recognized on the consolidated balance sheets
Other Liabilities				$ 3,894,000	$ 2,454,000
Other Assets				3,105,000
Accumulated other comprehensive income / (loss), net of tax				1,418,000	(3,481,000)
Amounts recognized in accumulated other comprehensive loss
Net actuarial gain/(loss)				(386,000)	(5,836,000)
Accumulated other comprehensive loss, pre-tax				(386,000)	(5,836,000)
Accumulated other comprehensive income / (loss), net of tax				1,418,000	$ (3,481,000)
Components of the plan's net periodic pension cost
Service cost	1,308,000	652,000	612,000
Interest cost	2,002,000	766,000	720,000
Expected return on plan assets	(2,024,000)	(813,000)	(848,000)
Amortization of unrecognized net actuarial loss	1,271,000	245,000	218,000
Curtailment	128,000
Net periodic pension cost	2,685,000	850,000	$ 702,000
Additional disclosure
Expected contribution in 2017	833,000
Estimated Pension Benefits
2017				4,433,000
2018				4,001,000
2019				4,348,000
2020				4,461,000
2021				4,676,000
2022 - 2026				22,651,000
Total				44,570,000
Pension Benefit | Quoted Prices in Active Markets (Level 1)
Plan net assets:
Balance at end of year	62,053,000
Pension plan assets
Fair value of plan assets	62,053,000			62,053,000
Pension Benefit | Significant Other Observable Inputs (Level 2)
Plan net assets:
Balance at end of year	12,775,000
Pension plan assets
Fair value of plan assets	12,775,000			12,775,000
Pension Benefit | Level 3
Plan net assets:
Balance at end of year	503,000
Pension plan assets
Fair value of plan assets	503,000			503,000
Pension Benefit | Cash, cash equivalents, money markets and other
Plan net assets:
Balance at end of year	32,976,000
Pension plan assets
Fair value of plan assets	32,976,000			$ 32,976,000
Weighted-average asset allocations (as a percent)				43.80%	81.50%
Pension Benefit | Cash, cash equivalents, money markets and other | Quoted Prices in Active Markets (Level 1)
Plan net assets:
Balance at end of year	32,976,000
Pension plan assets
Fair value of plan assets	32,976,000			$ 32,976,000
Pension Benefit | Common stock - domestic
Plan net assets:
Balance at end of year	17,715,000
Pension plan assets
Fair value of plan assets	17,715,000			$ 17,715,000
Weighted-average asset allocations (as a percent)				23.50%	14.70%
Pension Benefit | Common stock - domestic | Quoted Prices in Active Markets (Level 1)
Plan net assets:
Balance at end of year	17,715,000
Pension plan assets
Fair value of plan assets	17,715,000			$ 17,715,000
Pension Benefit | Common stock - foreign
Plan net assets:
Balance at end of year	4,845,000
Pension plan assets
Fair value of plan assets	4,845,000			$ 4,845,000
Weighted-average asset allocations (as a percent)				6.40%
Pension Benefit | Common stock - foreign | Quoted Prices in Active Markets (Level 1)
Plan net assets:
Balance at end of year	3,629,000
Pension plan assets
Fair value of plan assets	3,629,000			$ 3,629,000
Pension Benefit | Common stock - foreign | Significant Other Observable Inputs (Level 2)
Plan net assets:
Balance at end of year	1,216,000
Pension plan assets
Fair value of plan assets	1,216,000			1,216,000
Pension Benefit | Mutual funds - equities
Plan net assets:
Balance at end of year	7,141,000
Pension plan assets
Fair value of plan assets	7,141,000			$ 7,141,000
Weighted-average asset allocations (as a percent)				9.50%
Pension Benefit | Mutual funds - equities | Quoted Prices in Active Markets (Level 1)
Plan net assets:
Balance at end of year	6,180,000
Pension plan assets
Fair value of plan assets	6,180,000			$ 6,180,000
Pension Benefit | Mutual funds - equities | Significant Other Observable Inputs (Level 2)
Plan net assets:
Balance at end of year	961,000
Pension plan assets
Fair value of plan assets	961,000			961,000
Pension Benefit | Exchange traded funds - equities
Plan net assets:
Balance at end of year	1,553,000
Pension plan assets
Fair value of plan assets	1,553,000			$ 1,553,000
Weighted-average asset allocations (as a percent)				2.10%
Pension Benefit | Exchange traded funds - equities | Quoted Prices in Active Markets (Level 1)
Plan net assets:
Balance at end of year	1,553,000
Pension plan assets
Fair value of plan assets	1,553,000			$ 1,553,000
Pension Benefit | Fixed income mutual funds
Plan net assets:
Balance at end of year	10,142,000
Pension plan assets
Fair value of plan assets	10,142,000			$ 10,142,000
Weighted-average asset allocations (as a percent)				13.50%
Pension Benefit | Fixed income mutual funds | Significant Other Observable Inputs (Level 2)
Plan net assets:
Balance at end of year	10,142,000
Pension plan assets
Fair value of plan assets	10,142,000			$ 10,142,000
Pension Benefit | Fixed income securities
Plan net assets:
Balance at end of year	456,000
Pension plan assets
Fair value of plan assets	456,000			$ 456,000
Weighted-average asset allocations (as a percent)				0.60%	3.80%
Pension Benefit | Fixed income securities | Significant Other Observable Inputs (Level 2)
Plan net assets:
Balance at end of year	456,000
Pension plan assets
Fair value of plan assets	456,000			$ 456,000
Pension Benefit | Annuities
Plan net assets:
Balance at end of year	503,000
Pension plan assets
Fair value of plan assets	503,000			$ 503,000
Weighted-average asset allocations (as a percent)				0.70%
Pension Benefit | Annuities | Level 3
Plan net assets:
Balance at end of year	503,000
Pension plan assets
Fair value of plan assets	503,000			$ 503,000
GTT Pension Benefit
Projected benefit obligations:
Balance at beginning of year	14,400,000
Balance at end of year	12,549,000	14,400,000
Funded status of plan
Projected benefit obligation	$ 14,400,000	$ 14,400,000		12,549,000	$ 14,400,000
Plan Net Assets				8,655,000	11,946,000
Under funded status of plan				(3,894,000)	$ (2,454,000)
GTT Pension Benefit | Minimum
Funded status of plan
Percentage of plan assets to be invested within Guyana	70.00%
GTT Pension Benefit | Maximum
Funded status of plan
Percentage of plan assets to be invested within Guyana	80.00%
Innovative Pension Benefit
Projected benefit obligations:
Balance at end of year	$ 63,571,000
Funded status of plan
Projected benefit obligation	63,571,000			63,571,000
Plan Net Assets				66,676,000
Under funded status of plan				$ 3,105,000
Postretirement Benefits
Weighted-average rates assumed in the actuarial calculations for the pension plan
Discount rate (as a percent)				3.90%
One-percentage change in assumed health care cost trend rates
Accumulated postretirement benefit obligation, At trend				$ 5,108,000
Accumulated postretirement benefit obligation, At trend +1%				5,487,000
Impact of Accumulated postretirement benefit obligation, At trend +1%	$ 379,000
Impact of Accumulated postretirement benefit obligation, At trend +1% (as a percent)	7.40%
Accumulated postretirement benefit obligation, At trend -1%				4,775,000
Impact of Accumulated postretirement benefit obligation, At trend -1%	$ (333,000)
Impact of Accumulated postretirement benefit obligation, At trend -1% (as a percent)	(6.50%)
Service cost plus interest cost, At trend	$ 194,000
Service cost plus interest cost, At Trend +1%	214,000
Impact of Service cost plus interest cost, At trend +1%	20,000
Impact of Service cost plus interest cost, At trend +1% (as a percent)	10.30
Service cost plus interest cost, At Trend -1%	177,000
Impact of Service cost plus interest cost, At trend -1%	$ (17,000)
Impact of Service cost plus interest cost, At trend -1% (as a percent)	(8.80%)
Projected benefit obligations:
Innovative acquisition	$ 5,472,000
Service cost	97,000
Interest cost	97,000
Benefits and settlements paid	(206,000)
Actuarial (gain) loss	(325,000)
Experience Loss	(27,000)
Balance at end of year	5,108,000
Plan net assets:
Company contributions	206,000
Benefits and settlements paid	(206,000)
Funded status of plan
Projected benefit obligation	5,108,000			5,108,000
Under funded status of plan				(5,108,000)
Restricted Cash and Cash Equivalents				5,100,000
Amounts recognized on the consolidated balance sheets
Accrued and current liabilities				381,000
Other Liabilities				4,727,000
Accumulated other comprehensive income / (loss), net of tax				352,000
Amounts recognized in accumulated other comprehensive loss
Net actuarial gain/(loss)				352,000
Accumulated other comprehensive loss, pre-tax				352,000
Accumulated other comprehensive income / (loss), net of tax				$ 352,000
Components of the plan's net periodic pension cost
Service cost	97,000
Interest cost	97,000
Net periodic pension cost	$ 194,000
Medical benefit plan
Health care cost trend rates
Trend rate	5.80%
Ultimate rate	4.50%
Dental benefit plan
Health care cost trend rates
Trend rate	4.00%
Ultimate rate	2.00%