FAIR VALUE MEASUREMENTS (Tables)

9 Months Ended

Sep. 30, 2015

Fair Value Disclosures [Abstract]

Financial instruments carried at fair value

Financial assets and liabilities carried at fair value as of September 30, 2015 are classified in the tables below in the categories described below (in thousands): 

	Level 1		Level 2		Total
ASSETS:
Cash equivalents:
U.S. Treasury money market funds	$	76,282	$	—	$	76,282
Foreign government securities	—		298,375		298,375
U.S. government securities	—		525,381		525,381
Commercial paper	—		20,910		20,910
Short-term investments:
Foreign government securities	—		71,832		71,832
U.S. government securities	—		638,394		638,394
Corporate debt securities	—		497,227		497,227
Commercial paper	—		1,716		1,716
U.S. government agency securities	—		2,015		2,015
Foreign exchange derivatives	—		358		358
Long-term investments:
Foreign government securities	—		485,974		485,974
U.S. government securities	—		778,214		778,214
Corporate debt securities	—		3,740,227		3,740,227
U.S. municipal securities	—		1,095		1,095
Ctrip convertible debt securities	—		699,475		699,475
Ctrip equity securities	622,645		—		622,645
Total assets at fair value	$	698,927	$	7,761,193	$	8,460,120

	Level 1		Level 2		Total
LIABILITIES:
Foreign exchange derivatives	$	—	$	317	$	317

Financial assets and liabilities carried at fair value as of December 31, 2014 are classified in the tables below in the categories described below (in thousands):

	Level 1		Level 2		Total
ASSETS:
Cash equivalents:
U.S. Treasury money market funds	$	155,608	$	—	$	155,608
Foreign government securities	—		974,855		974,855
U.S. government securities	—		676,503		676,503
Corporate debt securities	—		45,340		45,340
Commercial paper	—		382,544		382,544
U.S. government agency securities	—		10,000		10,000
Short-term investments:
Foreign government securities	—		52,490		52,490
U.S. government securities	—		364,266		364,266
Corporate debt securities	—		581,523		581,523
Commercial paper	—		39,092		39,092
U.S. government agency securities	—		104,811		104,811
Foreign exchange derivatives	—		336		336
Long-term investments:
Foreign government securities	—		12,671		12,671
U.S. government securities	—		556,448		556,448
Corporate debt securities	—		2,329,033		2,329,033
U.S. government agency securities	—		95,094		95,094
U.S. municipal securities	—		1,102		1,102
Ctrip convertible debt securities	—		425,961		425,961
Ctrip equity securities	335,344		—		335,344
Total assets at fair value	$	490,952	$	6,652,069	$	7,143,021

	Level 1		Level 2		Total
LIABILITIES:
Foreign exchange derivatives	$	—	$	129	$	129