GOODWILL AND INTANGIBLE ASSETS Goodwill (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Goodwill [Roll Forward]
Goodwill, Gross Beginning Balance	$ 1,174,971	$ 1,064,147
Accumulated Impairment Losses, Beginning Balance	(462,612)	(462,612)
Goodwill, Net Beginning Balance	676,333	712,359	$ 601,535
Foreign Currency	(36,026)	110,824
Accumulated Impairment Losses, Ending Balance	(462,612)	(462,612)
Goodwill, Gross Ending Balance	1,138,945	1,174,971
BULGARIA
Goodwill [Roll Forward]
Goodwill, Gross Beginning Balance	175,071	171,389
Accumulated Impairment Losses, Beginning Balance	(144,639)	(144,639)
Goodwill, Net Beginning Balance	29,055	30,432	26,750
Foreign Currency	(1,377)	3,682
Accumulated Impairment Losses, Ending Balance	(144,639)	(144,639)
Goodwill, Gross Ending Balance	173,694	175,071
CZECH REPUBLIC
Goodwill [Roll Forward]
Goodwill, Gross Beginning Balance	837,732	744,483
Accumulated Impairment Losses, Beginning Balance	(287,545)	(287,545)
Goodwill, Net Beginning Balance	521,425	550,187	456,938
Foreign Currency	(28,762)	93,249
Accumulated Impairment Losses, Ending Balance	(287,545)	(287,545)
Goodwill, Gross Ending Balance	808,970	837,732
ROMANIA
Goodwill [Roll Forward]
Goodwill, Gross Beginning Balance	90,305	82,786
Accumulated Impairment Losses, Beginning Balance	(11,028)	(11,028)
Goodwill, Net Beginning Balance	75,772	79,277	71,758
Foreign Currency	(3,505)	7,519
Accumulated Impairment Losses, Ending Balance	(11,028)	(11,028)
Goodwill, Gross Ending Balance	86,800	90,305
Slovak Republic [Member]
Goodwill [Roll Forward]
Goodwill, Gross Beginning Balance	52,463	46,089
Accumulated Impairment Losses, Beginning Balance	0	0
Goodwill, Net Beginning Balance	50,081	52,463	46,089
Foreign Currency	(2,382)	6,374
Accumulated Impairment Losses, Ending Balance	0	0
Goodwill, Gross Ending Balance	50,081	52,463
SLOVENIA
Goodwill [Roll Forward]
Goodwill, Gross Beginning Balance	19,400	19,400
Accumulated Impairment Losses, Beginning Balance	(19,400)	(19,400)
Goodwill, Net Beginning Balance	0	0	$ 0
Foreign Currency	0	0
Accumulated Impairment Losses, Ending Balance	(19,400)	(19,400)
Goodwill, Gross Ending Balance	$ 19,400	$ 19,400