Fair Value Measurements and Derivative Instruments (Non-Derivative Net Investment) (Details) - Foreign currency debt - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016
Net investment hedge
Amount of Gain (Loss) Recognized in Other Comprehensive Income (Effective Portion)	$ (38,971)	$ 20,295
Amount of Gain (Loss) Recognized in Income (Ineffective Portion and Amount Excluded from Effectiveness Testing)	0	0
Other income (expense)
Net investment hedge
Amount of Gain (Loss) Recognized in Income (Ineffective Portion and Amount Excluded from Effectiveness Testing)	$ 0	$ 0

Current period adjustment in other comprehensive income reflecting gains or losses on foreign currency transactions that are designated as, and are effective as, hedges of a net investment in a foreign entity, net of tax effect.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 830
-SubTopic 30
-Section 45
-Paragraph 20
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=64808268&loc=d3e32211-110900

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624171-113959

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