Summary of Significant Accounting Policies - Accumulated Other Comprehensive Income and Other Expenses (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Jun. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Accumulated other comprehensive items, net
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal				$ 0	$ 38,869
Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning Balance	$ (207,450)	$ (153,590)		(103,989)	(212,573)
Other comprehensive loss:
Foreign currency translation adjustments	(22,790)	38,247		(128,454)	97,230
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	1,980	0		4,183	0
Total Other comprehensive (loss) income	(20,810)	38,247		(124,271)	97,230
Accumulated Other Comprehensive Income (Loss), Net of Tax, Ending Balance	(228,260)	(115,343)	$ (153,590)	(228,260)	(115,343)
Total loss on foreign currency transactions	664	11,865		3,825	27,900
Debt extinguishment expense	0	48,298		0	48,298
Other, net	(339)	(684)		(2,405)	(42,449)
Other (Income) Expense, Net	325	59,479		1,420	33,749
Russia and Ukraine Divestment \| Disposal Group, Not Discontinued Operations
Accumulated other comprehensive items, net
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal			38,869		38,869
Other comprehensive loss:
Foreign currency translation adjustments					29,100
Foreign currency translation adjustments
Accumulated other comprehensive items, net
Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning Balance	(209,653)	(153,590)		(103,989)	(212,573)
Other comprehensive loss:
Foreign currency translation adjustments	(22,790)	38,247		(128,454)	97,230
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	0			0
Total Other comprehensive (loss) income	(22,790)	38,247		(128,454)	97,230
Accumulated Other Comprehensive Income (Loss), Net of Tax, Ending Balance	(232,443)	$ (115,343)	$ (153,590)	(232,443)	$ (115,343)
Market value adjustments for securities
Accumulated other comprehensive items, net
Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning Balance	2,203			0
Other comprehensive loss:
Foreign currency translation adjustments	0			0
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	1,980			4,183
Total Other comprehensive (loss) income	1,980			4,183
Accumulated Other Comprehensive Income (Loss), Net of Tax, Ending Balance	$ 4,183			$ 4,183

The net amount of other nonoperating income and expense which is not otherwise specified in the taxonomy.

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Accumulated change in equity from transactions and other events and circumstances from non-owner sources, net of tax effect, at period end. Excludes Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge.

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Amount before tax of gain (loss) recognized on the sale or disposal of a disposal group. Excludes discontinued operations.

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

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