UNAUDITED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2017	Mar. 31, 2016
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Net income		$ 455,623	$ 374,424
Other comprehensive income, net of tax
Foreign currency translation adjustments	[1]	35,805	77,372
Unrealized (loss) gain on marketable securities	[2]	345,934	(24,459)
Comprehensive income		$ 837,362	$ 427,337

[1] Foreign currency translation adjustments include a tax benefit of $19,733 and $61,096 for the three months ended March 31, 2017 and 2016, respectively, associated with net investment hedges (See Note 10). The remaining balance in foreign currency translation adjustments excludes income taxes as a result of the Company's intention to indefinitely reinvest the earnings of its international subsidiaries outside of the United States (See Note 9).

[2] Net of a tax charge of $7,855 and $29,128 for the three months ended March 31, 2017 and 2016, respectively. Unrealized gain (loss) on marketable securities includes a net unrealized gain of $323,688 for the three months ended March 31, 2017, compared to a net unrealized loss of $113,152 for three months ended March 31, 2016 on the Company's investments in Ctrip.com International Ltd. ("Ctrip"), which were exempt from tax in the Netherlands.