Investments (Tables)

3 Months Ended

Dec. 31, 2011

Notes to Financial Statements [Abstract]

Summary of available-for-sale securities

The following is a summary of available-for-sale and marketable equity securities at December 31, 2011 (amounts in thousands):

	Available-for-sale Securities
	Adjusted Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
Government agency bonds	$	405,320	$	549	$	(169	)	$	405,700
Municipal bonds	17,628		121		—			17,749
Auction rate securities	11,691		—		—			11,691
Corporate bonds and debt	725,156		2,277		(4,172		)	723,261
Marketable equity securities	6,820		—		(587		)	6,233
	$	1,166,615	$	2,947	$	(4,928	)	$	1,164,634

 The following is a summary of available-for-sale and marketable equity securities at March 31, 2011 (amounts in thousands):

	Available-for-sale Securities
	Adjusted Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
Government agency bonds	$	431,355	$	159	$	(923	)	$	430,591
Municipal bonds	11,445		34		(22		)	11,457
Auction rate securities	12,475		—		—			12,475
Corporate bonds and debt	519,499		4,116		(589		)	523,026
Marketable equity securities	26,173		688		—			26,861
	$	1,000,947	$	4,997	$	(1,534	)	$	1,004,410

Summary of amortized cost and estimated fair value of available-for-sale securities, by maturity

The amortized cost and estimated fair value of the available-for-sale securities at December 31, 2011, by maturity, excluding marketable equity securities of $6.2 million and corporate debt of $4.6 million, which have no contractual maturity, are shown below (amounts in thousands).  Expected maturities can differ from contractual maturities because the issuers of the securities may have the right to prepay obligations without prepayment penalties, and the Company views its available-for-sale securities as available for current operations.

	Adjusted Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
Available-for-sale
Due in one year or less	$	206,919	$	1,045	$	(332	)	$	207,632
Due after one year and through five years	936,560		1,902		(4,009		)	934,453
Due after five years and through ten years	—		—		—			—
Due after ten years	11,691		—		—			11,691
	$	1,155,170	$	2,947	$	(4,341	)	$	1,153,776