GOODWILL AND INTANGIBLE ASSETS Goodwill (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Goodwill [Roll Forward]
Goodwill, Gross Beginning Balance	$ 1,044,747	$ 1,064,904
Accumulated Impairment Losses, Beginning Balance	(443,212)	(443,212)
Goodwill, Net Beginning Balance	712,359	601,535	$ 621,692
Foreign Currency	110,824	(20,157)
Accumulated Impairment Losses, Ending Balance	(443,212)	(443,212)
Goodwill, Gross Ending Balance	1,155,571	1,044,747
BULGARIA
Goodwill [Roll Forward]
Goodwill, Gross Beginning Balance	171,389	172,365
Accumulated Impairment Losses, Beginning Balance	(144,639)	(144,639)
Goodwill, Net Beginning Balance	30,432	26,750	27,726
Foreign Currency	3,682	(976)
Accumulated Impairment Losses, Ending Balance	(144,639)	(144,639)
Goodwill, Gross Ending Balance	175,071	171,389
CZECH REPUBLIC
Goodwill [Roll Forward]
Goodwill, Gross Beginning Balance	744,483	759,491
Accumulated Impairment Losses, Beginning Balance	(287,545)	(287,545)
Goodwill, Net Beginning Balance	550,187	456,938	471,946
Foreign Currency	93,249	(15,008)
Accumulated Impairment Losses, Ending Balance	(287,545)	(287,545)
Goodwill, Gross Ending Balance	837,732	744,483
ROMANIA
Goodwill [Roll Forward]
Goodwill, Gross Beginning Balance	82,786	85,443
Accumulated Impairment Losses, Beginning Balance	(11,028)	(11,028)
Goodwill, Net Beginning Balance	79,277	71,758	74,415
Foreign Currency	7,519	(2,657)
Accumulated Impairment Losses, Ending Balance	(11,028)	(11,028)
Goodwill, Gross Ending Balance	90,305	82,786
Slovak Republic [Member]
Goodwill [Roll Forward]
Goodwill, Gross Beginning Balance	46,089	47,605
Accumulated Impairment Losses, Beginning Balance	0	0
Goodwill, Net Beginning Balance	52,463	46,089	$ 47,605
Foreign Currency	6,374	(1,516)
Accumulated Impairment Losses, Ending Balance	0	0
Goodwill, Gross Ending Balance	$ 52,463	$ 46,089