INCOME TAXES - Components of Income Tax Expense (Benefit) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current:
United States-Federal									$ 24,546	$ 375	$ 15,763
United States-State									4,506	500	505
Foreign									13,060	11,289	10,528
Total current income tax expense									42,112	12,164	26,796
Deferred:
United States-Federal									(17,947)	(10,892)	(1,880)
United States-State									(2,832)	950	(291)
Foreign									(2,463)	(3,563)	(3,465)
Total deferred income tax expense (benefit)									(23,242)	(13,505)	(5,636)
Consolidated:
United States-Federal									6,599	(10,517)	13,883
United States-State									1,674	1,450	214
Foreign									10,597	7,726	7,063
Total income tax expense (benefit)	$ 5,851	$ 7,010	$ 2,088	$ 3,921	$ (6,181)	$ (884)	$ 2,596	$ 3,128	18,870	(1,341)	$ 21,160
Deferred tax assets:
Receivables reserve	3,087				1,524				3,087	1,524
Temporary differences not currently deductible for tax	9,035				7,869				9,035	7,869
Deferred compensation	784				1,446				784	1,446
Pension	635				245				635	245
Net operating losses	29,496				26,685				29,496	26,685
Tax Credits	645				8,969				645	8,969
Total deferred tax asset	43,682				46,738				43,682	46,738
Deferred tax liabilities:
Property, plant and equipment, net	14,608				35,630				14,608	35,630
Intangible assets, net	5,959				5,817				5,959	5,817
Total deferred tax liabilities	20,567				41,447				20,567	41,447
Valuation allowance	(31,442)				(35,829)				(31,442)	(35,829)
Net deferred tax liabilities	(8,327)				(30,538)				(8,327)	(30,538)
Deferred tax assets:
Long term	1,949				1,194				1,949	1,194
Total deferred tax asset	1,949				1,194				1,949	1,194
Deferred tax liabilities:
Long term	(10,276)				(31,732)				(10,276)	(31,732)
Total deferred tax liabilities	(10,276)				(31,732)				(10,276)	(31,732)
Net deferred tax liabilities	$ (8,327)				$ (30,538)				$ (8,327)	$ (30,538)