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, 2013 and 2012 are as follows:


	Amortized Cost		Unrealized Gains		Unrealized (Losses)			Fair Value
As of January 31, 2013
Short-term Investments:
Corporate bonds	$	88,432	$	106	$	(23	)	$	88,515
Municipal and pre-refunded municipal bonds		63,355		85		(17	)		63,423
Certificates of deposit		40,870		25		—			40,895
Treasury bills		21,354		14		—			21,368
Commercial paper		10,775		8		(2	)		10,781
Federal government agencies		3,500		4		—			3,504

		228,286		242		(42	)		228,486

Long-term Investments:
Corporate bonds		64,219		102		(61	)		64,260
Municipal and pre-refunded municipal bonds		52,925		76		(60	)		52,941
Certificates of deposit		2,340		—		—			2,340
Treasury bills		19,724		13		—			19,737
Federal government agencies		5,974		5		(2	)		5,977
Auction rate securities		4,925		—		(595	)		4,330

		150,107		196		(718	)		149,585

	$	378,393	$	438	$	(760	)	$	378,071

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
Certificates of deposit		5,225		—		—			5,225
Commercial paper		3,580		12		—			3,592
Federal government agencies		4,513		2		—			4,515

		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
Certificates of deposit		6,970		—		(1	)		6,969
Treasury bills		14,982		6		—			14,988
Federal government agencies		5,111		2		(1	)		5,112
Auction rate securities		22,975		—		(2,778	)		20,197

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

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

Proceeds from the sale and maturities of available-for-sale securities were $207,576, $414,769 and $571,236 in fiscal 2013, 2012 and 2011, respectively. The Company included in interest income, in the Consolidated Statements of Income, a net realized gain of $248 during fiscal 2013, a net realized gain of $1,171 during fiscal 2012 and a net realized loss of $30 during fiscal 2011. Amortization of discounts and premiums, net, resulted in a reduction of interest income of $5,276, $7,373 and $8,702 for fiscal years 2013, 2012 and 2011, 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, 2013 and January 31, 2012, respectively.


	January 31, 2013
	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		74,537		(85	)		—		—			74,537		(85	)
Municipal and pre-refunded municipal bonds		42,826		(77	)		1,413		—			44,239		(77	)
Certificates of deposit		3,400		—			244		—			3,644		—
Commercial paper		2,994		(1	)		—		—			2,994		(1	)
Federal government agencies		1,998		(2	)		—		—			1,998		(2	)
Auction rate securities		—		—			4,330		(595	)		4,330		(595	)

Total		125,755		(165	)		5,987		(595	)		131,742		(760	)


	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	)
Certificates of deposit		1,489		(1	)		—		—			1,489		(1	)
Treasury bills		1,039		—			—		—			1,039		—
Federal government agencies		1,099		(1	)		—		—			1,099		(1	)
Auction rate securities		—		—			20,197		(2,778	)		20,197		(2,778	)

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

As of January 31, 2013 and 2012, there were a total of 342 and 76 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, 2013 and 2012 was $595 and $2,778, 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, 2013, the par value of our ARS was $4,925 and the estimated fair value was $4,330. Our ARS portfolio consists of “A” or better rated ARS that represent interests in municipal debt obligations. 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.