CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 127,588	$ 80,098
Other comprehensive income (loss):
Foreign currency translation	3,827	12,203
Unrealized gain (loss) on marketable debt securities	9,291	(172)
Derivative instruments	(5,438)	8,615
Total other comprehensive income	7,680	20,646
Comprehensive income	135,268	100,744
Comprehensive income attributable to noncontrolling interests	1,803	1,395
Comprehensive income attributable to common stockholders	$ 133,465	$ 99,349

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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Amount after tax, before reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature.

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Amount, after tax and reclassification, of gain (loss) from derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness.

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