SEGMENT DATA Long Lived Assets (Details) - USD ($) $ in Thousands		Dec. 31, 2017		Dec. 31, 2016		Dec. 31, 2015
Segment Reporting Information [Line Items]
Assets	[1]	$ 1,628,055		$ 1,390,717
Long-lived assets		103,648	[2]	89,080	[2]	$ 87,943
BULGARIA
Segment Reporting Information [Line Items]
Assets	[1]	155,885		130,873
Long-lived assets	[2]	7,863		6,280
CZECH REPUBLIC
Segment Reporting Information [Line Items]
Assets	[1]	842,716		700,190
Long-lived assets	[2]	46,146		39,529
ROMANIA
Segment Reporting Information [Line Items]
Assets	[1]	307,286		266,132
Long-lived assets	[2]	28,515		22,796
Slovak Republic [Member]
Segment Reporting Information [Line Items]
Assets	[1]	149,866		131,220
Long-lived assets	[2]	17,450		15,326
Total operating segments [Member]
Segment Reporting Information [Line Items]
Assets	[1]	1,455,753		1,228,415
Long-lived assets	[2]	99,974		83,931
Corporate [Member]
Segment Reporting Information [Line Items]
Assets	[1]	24,146		40,786
Long-lived assets	[2]	$ 3,674		$ 5,149

[1] Segment assets exclude any intercompany balances.

[2] Reflects property, plant and equipment, net.