Derivatives and Hedging Activities - Hedges (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Net investment hedges [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of gain or (loss) recognized in accumulated other comprehensive income		$ 226,115		$ 151,843
Amount of gain or (loss) recognized in accumulated other comprehensive income	$ (37,857)		$ 38,983
Amount of gain or (loss) excluded from effectiveness testing included in income	4,928		9,091
Amount of gain or (loss) recognized in earnings		0		0
Cash flow hedges [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of gain or (loss) excluded from effectiveness testing included in income	(17)		71
Amount of gain or (loss) recognized in earnings		4,777		6,430
Amount of gain or (loss) recognized in accumulated other comprehensive income	(4,004)		6,961
Amount of gain or (loss) recognized in accumulated other comprehensive income		47,031		41,590
Amount of gain or (loss) reclassified from accumulated other comprehensive income to income	8,939		13,471
Amount of gain or (loss) reclassified from accumulated other comprehensive income to income		(6,126)		(15,218)
Foreign currency debt [Member] | Net investment hedges [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of gain or (loss) recognized in accumulated other comprehensive income	(34,309)		29,606
Amount of gain or (loss) recognized in accumulated other comprehensive income		226,115		151,843
Cross-currency interest rate swap [Member] | Net investment hedges [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of gain or (loss) recognized in accumulated other comprehensive income	(9,689)		5,826
Amount of gain or (loss) recognized in accumulated other comprehensive income		0		0
Cross-currency interest rate swap [Member] | Net investment hedges [Member] | Excluding component [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of gain or (loss) recognized in accumulated other comprehensive income		0		0
Amount of gain or (loss) recognized in accumulated other comprehensive income	6,141		3,551
Cross-currency interest rate swap [Member] | Net investment hedges [Member] | Interest expense [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of gain or (loss) excluded from effectiveness testing included in income	4,928		9,091
Cross-currency interest rate swap [Member] | Net investment hedges [Member] | Interest expense [Member] | Excluding component [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of gain or (loss) recognized in earnings		0		0
Foreign currency forward and option contracts [Member] | Cash flow hedges [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of gain or (loss) recognized in accumulated other comprehensive income	(2,599)		8,366
Amount of gain or (loss) recognized in accumulated other comprehensive income		47,031		41,590
Foreign currency option contracts [Member] | Cash flow hedges [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of gain or (loss) recognized in accumulated other comprehensive income	(1,405)		(1,405)
Amount of gain or (loss) recognized in accumulated other comprehensive income		0		0
Foreign currency option contracts [Member] | Cash flow hedges [Member] | Revenues [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of gain or (loss) excluded from effectiveness testing included in income	(17)		(17)
Amount of gain or (loss) recognized in earnings		0		0
Foreign currency forward contract [Member] | Cash flow hedges [Member] | Cost of revenues [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of gain or (loss) reclassified from accumulated other comprehensive income to income	(9,745)		(15,074)
Amount of gain or (loss) reclassified from accumulated other comprehensive income to income		6,778		16,101
Foreign currency forward contract [Member] | Cash flow hedges [Member] | Other income (expense) [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of gain or (loss) excluded from effectiveness testing included in income	0		88
Amount of gain or (loss) recognized in earnings		4,777		6,430
Foreign currency forward contract [Member] | Cash flow hedges [Member] | Revenues [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of gain or (loss) reclassified from accumulated other comprehensive income to income	$ 18,684		$ 28,545
Amount of gain or (loss) reclassified from accumulated other comprehensive income to income		$ (12,904)		$ (31,319)