SEGMENT DATA Total Assets (Details) - USD ($) $ in Thousands		Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Assets	[1]	$ 1,628,055	$ 1,390,717
BULGARIA
Segment Reporting Information [Line Items]
Assets	[1]	155,885	130,873
CZECH REPUBLIC
Segment Reporting Information [Line Items]
Assets	[1]	842,716	700,190
ROMANIA
Segment Reporting Information [Line Items]
Assets	[1]	307,286	266,132
Slovak Republic [Member]
Segment Reporting Information [Line Items]
Assets	[1]	149,866	131,220
Total operating segments [Member]
Segment Reporting Information [Line Items]
Assets	[1]	1,455,753	1,228,415
Corporate [Member]
Segment Reporting Information [Line Items]
Assets	[1]	$ 24,146	$ 40,786

[1] Segment assets exclude any intercompany balances.