3. Marketable Securities

During all periods shown, marketable securities are classified as available-for-sale. The amortized cost, gross unrealized gains (losses) and fair values of available-for-sale securities by major security type and class of security as of January 31, 2012 and 2011 are as follows:


	Amortized Cost		Unrealized Gains		Unrealized (Losses)			Fair Value
As of January 31, 2012
Short-term Investments:
Corporate bonds	$	34,899	$	7	$	(28	)	$	34,878
Municipal and pre-refunded municipal bonds		41,519		135		(10	)		41,644
Certificate of deposit		5,225		—		—			5,225
Federal government agencies		4,513		2		—			4,515
Commercial paper		3,580		12		—			3,592

		89,736		156		(38	)		89,854

Long-term Investments:
Corporate bonds		60,852		277		(72	)		61,057
Municipal and pre-refunded municipal bonds		18,410		186		(6	)		18,590
Auction rate securities		22,975		—		(2,778	)		20,197
Treasury bills		14,982		6		—			14,988
Certificate of deposit		6,970		—		(1	)		6,969
Federal government agencies		5,111		2		(1	)		5,112

		129,300		471		(2,858	)		126,913

	$	219,036	$	627	$	(2,896	)	$	216,767

As of January 31, 2011
Short-term Investments:
Municipal and pre-refunded municipal bonds	$	42,996	$	48	$	(9	)	$	43,035
Treasury bills		7,004		4		—			7,008
Federal government agencies		40,842		80		—			40,922
FDIC insured corporate bonds		23,489		66		—			23,555
Variable rate demand notes		1,900		—		—			1,900

		116,231		198		(9	)		116,420

Long-term Investments:
Corporate bonds		137,540		173		(154	)		137,559
Municipal and pre-refunded municipal bonds		143,711		216		(558	)		143,369
Auction rate securities		33,250		—		(3,788	)		29,462
Treasury bills		23,311		34		—			23,345
Federal government agencies		18,225		30		(2	)		18,253

		356,037		453		(4,502	)		351,988

	$	472,268	$	651	$	(4,511	)	$	468,408

Proceeds from the sale and maturities of available-for-sale securities were $414,769, $571,236 and $421,040 in fiscal 2012, 2011 and 2010, respectively. The Company included in interest income, in the Consolidated Statements of Income, a net realized gain of $1,171 during fiscal 2012, a net realized loss of $30 during fiscal 2011 and a net realized gain of $1,075 during fiscal 2010. Amortization of discounts and premiums, net, resulted in a reduction to interest income of $7,373, $8,702 and $6,204 for fiscal years 2012, 2011, and 2010, respectively.

The following tables show the gross unrealized losses and fair value of the Company's marketable securities with unrealized losses that are not deemed to be other-than-temporarily impaired aggregated by the length of time that individual securities have been in a continuous unrealized loss position, at January 31, 2012 and January 31, 2011, respectively.


	January 31, 2012
	Less Than 12 Months					12 Months or Greater					Total
Description of Securities	Fair Value		Unrealized Losses			Fair Value		Unrealized Losses			Fair Value		Unrealized Losses
Corporate bonds		45,089		(100	)		—		—			45,089		(100	)
Municipal and pre-refunded municipal bonds		9,985		(9	)		2,954		(7	)		12,939		(16	)
Auction rate securities		—		—			20,197		(2,778	)		20,197		(2,778	)
Treasury bills		1,039		—			—		—			1,039		—
Certificate of deposit		1,489		(1	)		—		—			1,489		(1	)
Federal government agencies		1,099		(1	)		—		—			1,099		(1	)

Total		58,701		(111	)		23,151		(2,785	)		81,852		(2,896	)


	January 31, 2011
	Less Than 12 Months					12 Months or Greater					Total
Description of Securities	Fair Value		Unrealized Losses			Fair Value		Unrealized Losses			Fair Value		Unrealized Losses
FDIC insured corporate bonds		67,359		(154	)		—		—			67,359		(154	)
Municipal and pre-refunded municipal bonds		103,090		(567	)		—		—			103,090		(567	)
Auction rate securities		—		—			29,462		(3,788	)		29,462		(3,788	)
Federal government agencies		1,397		(2	)		—		—			1,397		(2	)

Total		171,846		(723	)		29,462		(3,788	)		201,308		(4,511	)

As of January 31, 2012 and 2011, there were a total of 76 and 128 issued securities with unrealized loss positions within the Company's portfolio, respectively. The total unrealized loss position due to the impairment of ARS held by the Company that have experienced auction failures as of January 31, 2012 and 2011 was $2,778 and $3,788, respectively. The Company deemed all of these securities as temporarily impaired. The unrealized loss positions were primarily due to auction failures of the ARS held and fluctuations in the market interest rates for remaining securities. The Company believes it has the ability to realize the full value of all of these investments upon maturity or redemption.

As of January 31, 2012, the par value of our ARS was $22,975 and the estimated fair value was $20,197. Our ARS portfolio consists of "A" or better rated ARS that represent interests in municipal and student loan related collateralized debt obligations, all of which are guaranteed by either government agencies and/or insured by private insurance agencies at 97% or greater of par value. To date, we have collected all interest payable on outstanding ARS when due and have not been informed by the issuers that accrued interest payments are currently at risk. The Company does not have the intent to sell the underlying securities prior to their recovery and the Company believes it is not likely that it will be required to sell the underlying securities prior to their anticipated recovery of full amortized cost.