Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
Jun. 30, 2019	Jun. 30, 2018
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 88,923	$ 90,066
Other comprehensive income (loss):
Foreign currency translation gains (losses)	2,334	(6,852)
Net unrealized gains (losses) on marketable securities	600	143
Other comprehensive income (loss)	2,934	(6,709)
Comprehensive income	$ 91,857	$ 83,357

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 and 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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