FAIR VALUE MEASUREMENTS (Tables)

6 Months Ended

Jun. 30, 2016

Fair Value Disclosures [Abstract]

Financial instruments carried at fair value

Financial assets and liabilities carried at fair value as of June 30, 2016 are classified in the tables below in the categories described below (in thousands): 

	Level 1		Level 2		Total
ASSETS:
Cash equivalents:
Money market funds	$	1,344,815	$	—	$	1,344,815
U.S. government securities	—		222,264		222,264
Commercial paper	—		5,560		5,560
Short-term investments:
Foreign government securities	—		287,112		287,112
U.S. government securities	—		427,535		427,535
Corporate debt securities	—		951,211		951,211
Commercial paper	—		8,007		8,007
U.S. government agency securities	—		3,377		3,377
Foreign exchange derivatives	—		782		782
Long-term investments:
Foreign government securities	—		646,437		646,437
U.S. government securities	—		547,230		547,230
Corporate debt securities	—		4,583,347		4,583,347
U.S. municipal securities	—		1,074		1,074
U.S. government agency securities	—		1,000		1,000
Ctrip convertible debt securities	—		1,306,475		1,306,475
Ctrip equity securities	868,851		—		868,851
Total assets at fair value	$	2,213,666	$	8,991,411	$	11,205,077

	Level 1		Level 2		Total
LIABILITIES:
Foreign exchange derivatives	$	—	$	351	$	351

Financial assets and liabilities carried at fair value as of December 31, 2015 are classified in the tables below in the categories described below (in thousands):

	Level 1		Level 2		Total
ASSETS:
Cash equivalents:
Money market funds	$	99,117	$	—	$	99,117
Foreign government securities	—		10,659		10,659
U.S. government securities	—		90,441		90,441
Corporate debt securities	—		1,855		1,855
Commercial paper	—		335,663		335,663
Short-term investments:
Foreign government securities	—		395,797		395,797
U.S. government securities	—		456,494		456,494
Corporate debt securities	—		305,260		305,260
Commercial paper	—		11,688		11,688
U.S. government agency securities	—		2,007		2,007
Foreign exchange derivatives	—		363		363
Long-term investments:
Foreign government securities	—		719,631		719,631
U.S. government securities	—		578,450		578,450
Corporate debt securities	—		4,276,614		4,276,614
U.S. municipal securities	—		1,083		1,083
Ctrip convertible debt securities	—		1,378,550		1,378,550
Ctrip equity securities	977,035		—		977,035
Total assets at fair value	$	1,076,152	$	8,564,555	$	9,640,707

	Level 1		Level 2		Total
LIABILITIES:
Foreign exchange derivatives	$	—	$	644	$	644