Income Taxes - Earnings Before Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Earnings before income taxes
Earnings before income taxes	$ 40,253	$ 57,245	$ 12,261
U.S.
Earnings before income taxes
Earnings before income taxes	9,315	25,746	(141)
Non-U.S.
Earnings before income taxes
Earnings before income taxes	$ 30,938	$ 31,499	$ 12,402

Amount of income (loss) from continuing operations before deduction of income tax expense (benefit) and income (loss) attributable to noncontrolling interest, and addition of income (loss) from equity method investments.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(h)(1)(i))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

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