Stockholders' Equity - Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss	$ 2,115,104	$ 1,587,282
Accumulated Foreign Currency Adjustment Attributable to Parent
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss	(1,040,716)	(927,221)
Accumulated Foreign Currency Adjustment Attributable to Noncontrolling Interest
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss	159	(33)
Accumulated Foreign Currency Adjustment Including Portion Attributable to Noncontrolling Interest
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss	(1,040,557)	(927,254)
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss	16,993	4,657
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Noncontrolling Interest
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss	0	0
Accumulated Net Gain (Loss) from Cash Flow Hedges Including Portion Attributable to Noncontrolling Interest
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss	16,993	4,657
Accumulated Defined Benefit Plans Adjustment Attributable to Parent
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss	(2,616)	(2,992)
Accumulated Defined Benefit Plans Adjustment Attributable to Noncontrolling Interest
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss	0	0
Accumulated Defined Benefit Plans Adjustment Including Portion Attributable to Noncontrolling Interest
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss	(2,616)	(2,992)
Accumulated other comprehensive (loss) income
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss	(1,026,339)	(925,556)
AOCI Attributable to Noncontrolling Interest
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss	159	(33)
Accumulated other comprehensive (loss) income
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss	$ (1,026,180)	$ (925,589)