Changes in Shareholders' Equity (Narrative) (Details) $ in Thousands	12 Months Ended
Dec. 31, 2017 USD ($)
ASC 606 [Member]
Increase decrease in retained earnings	$ 5,600
Increase decrease in non controlling interest	300
ASU 2016-16 [Member]
Increase decrease in retained earnings	$ 500

Net Increase or Decrease in balance of noncontrolling interest in the subsidiary during the reporting period.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 45
-Paragraph 16
-URI http://asc.fasb.org/extlink&oid=108774443&loc=SL4568740-111683

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration