Other (Income) Expense, Net (Foreign Currency (Gain ) Loss by Currency) (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Other Nonoperating Income (Expense)	$ 24	$ 47	$ (849)	$ 51
Foreign exchange	358	433	455	1,212
Angola, Kwanza
Foreign exchange	(4)	43	(3)	505
British Pound [Member]
Foreign exchange	(74)	247	(55)	475
Euro [Member]
Foreign exchange	732	(40)	835	170
Mexican Peso [Member]
Foreign exchange	11	114	(28)	136
Russian Ruble [Member]
Foreign exchange	(141)	(57)	(125)	(93)
Other Currencies Net [Member]
Foreign exchange	$ (166)	$ 126	$ (169)	$ 19

Amount before tax of foreign currency transaction realized and unrealized gain (loss) recognized in the income statement.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 830
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6450222&loc=d3e30840-110895

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 830
-SubTopic 20
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=64836518&loc=d3e30700-110894

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 830
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=64836518&loc=d3e30690-110894

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration