Fair Value Measurements (Tables)

12 Months Ended

Mar. 31, 2016

Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]

Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]

Assets measured at fair value on a recurring basis at March 31, 2016 are as follows (amounts in thousands):

	Quoted Prices in Active Markets for  Identical Instruments (Level 1)		Significant Other Observable Inputs (Level 2)		Significant  Unobservable Inputs (Level 3)		Total Balance
Assets
Cash and cash equivalents:
Money market mutual funds	$	1,787,446	$	—	$	—	$	1,787,446
Deposit accounts	—		305,305		—		305,305
Short-term investments:
Marketable equity securities	2,203		—		—		2,203
Corporate bonds and debt	—		1,000		—		1,000
Government agency bonds	—		350,081		—		350,081
Long-term investments:
Government agency bonds	—		118,549		—		118,549
Total assets measured at fair value	$	1,789,649	$	774,935	$	—	$	2,564,584

Assets measured at fair value on a recurring basis at March 31, 2015 are as follows (amounts in thousands):

	Quoted Prices in Active Markets for Identical Instruments (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total Balance
Assets
Cash and cash equivalents:
Money market mutual funds	$	279,833	$	—	$	—	$	279,833
Deposit accounts	—		327,982		—		327,982
Short-term investments:
Marketable equity securities	13,166		—		—		13,166
Corporate bonds and debt	—		756,664		—		756,664
Time deposits (1)	—		506		—		506
Government agency bonds	—		549,737		—		549,737
Municipal bonds	—		30,981		—		30,981
Long-term investments:
Corporate bonds and debt	—		164,075		6,190		170,265
Government agency bonds	—		192,519		—		192,519
Municipal bonds	—		10,717		—		10,717
Auction rate securities	—		—		9,825		9,825
Other assets
Derivative assets	—		8,928		—		8,928
Total assets measured at fair value	$	292,999	$	2,042,109	$	16,015	$	2,351,123

Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]

The following table presents a reconciliation for all assets measured at fair value on a recurring basis, excluding accrued interest components, using significant unobservable inputs (Level 3) for the year ended March 31, 2016. There were no changes in the fair value of these assets measured on a recurring basis during fiscal 2015 (amounts in thousands):

Year ended March 31, 2016	Auction Rate Securities			Corporate Debt			Total Gains (Losses)
Balance at March 31, 2015	$	9,825		$	6,190		$	—
Total gains (losses) (realized):
Included in earnings	2,780			(3,995		)	(1,215		)
Purchases, sales, issuances, and settlements, net	(12,605		)	—			—
Transfers out of Level 3	—			(2,195		)	—
Balance at March 31, 2016	$	—		$	—		$	(1,215	)