Fair Value Of Financial Assets And Financial Liabilities (Tables)

9 Months Ended

Oct. 31, 2011

Fair Value Of Financial Assets And Financial Liabilities [Abstract]

Financial Assets Measured At Fair Value On A Recurring Basis


	Marketable Securities Fair Value as of October 31, 2011
	Level 1		Level 2		Level 3		Total
Assets:
Corporate bonds	$	81,407	$	—	$	—	$	81,407
Municipal and pre-refunded municipal bonds		—		64,462		—		64,462
Auction rate securities		—		—		20,956		20,956
Certificate of deposit		6,969		—		—		6,969
Federal government agencies		2,001		—		—		2,001

	$	90,377	$	64,462	$	20,956	$	175,795


	Marketable Securities Fair Value as of January 31, 2011
	Level 1		Level 2		Level 3		Total
Assets:
Corporate bonds	$	137,559	$	—	$	—	$	137,559
Municipal and pre-refunded municipal bonds		—		186,404		—		186,404
Auction rate securities		—		—		29,462		29,462
Federal government agencies		59,175		—		—		59,175
Treasury bills		30,353		—		—		30,353
FDIC insured corporate bonds		23,555		—		—		23,555
Variable demand notes		—		1,900		—		1,900

	$	250,642	$	188,304	$	29,462	$	468,408


	Marketable Securities Fair Value as of October 31, 2010
	Level 1		Level 2		Level 3		Total
Assets:
Municipal and pre-refunded municipal bonds	$	—	$	217,181	$	—	$	217,181
Auction rate securities		—		—		30,143		30,143
Federal government agencies		75,787		—		—		75,787
Treasury bills		39,565		—		—		39,565
FDIC insured corporate bonds		41,679		—		—		41,679
Variable rate demand notes		—		31,925		—		31,925

	$	157,031	$	249,106	$	30,143	$	436,280

Reconciliation Of Beginning And Ending ARS Balances


	Three Months Ended October 31, 2011			Fiscal Year Ended January 31, 2011			Three Months Ended October 31, 2010
Balance at beginning of period	$	23,504		$	33,505		$	31,457
Total gains realized/unrealized:
Included in earnings		—			—			—
Included in other comprehensive income		327			332			161
Settlements		(2,875	)		(4,375	)		(1,475	)
Transfers in and/or out of Level 3		—			—			—

Balance at end of period	$	20,956		$	29,462		$	30,143

Unrealized losses included in accumulated other comprehensive loss related to assets still held at reporting date	$	(2,694	)	$	(3,788	)	$	(3,707	)

Total gains for the period included in earnings attributable to the change in unrealized gains or losses related to assets still held at reporting date	$	—		$	—		$	—


	Nine Months Ended October 31, 2011			Nine Months Ended October 31, 2010
Balance at beginning of period	$	29,462		$	33,505
Total gains realized/unrealized:
Included in earnings		—			—
Included in other comprehensive income		1,094			413
Settlements		(9,600	)		(3,775	)
Transfers in and/or out of Level 3		—			—

Balance at end of period	$	20,956		$	30,143
Unrealized losses included in accumulated other comprehensive loss related to assets still held at reporting date	$	(2,694	)	$	(3,707	)

Total gains for the period included in earnings attributable to the change in unrealized gains or losses related to assets still held at reporting date	$	—		$	—

- Definition

Tabular disclosure of assets, including [financial] instruments measured at fair value that are classified in stockholders' equity, if any, by class that are measured at fair value on a recurring basis. The disclosures contemplated herein include the fair value measurements at the reporting date by the level within the fair value hierarchy in which the fair value measurements in their entirety fall, segregating fair value measurements using quoted prices in active markets for identical assets (Level 1), significant other observable inputs (Level 2), and significant unobservable inputs (Level 3).

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- Definition

Tabular disclosure of the fair value measurement of liabilities using significant unobservable inputs (Level 3), a reconciliation of the beginning and ending balances, separately presenting changes during the period attributable to the following: (1) total gains or losses for the period (realized and unrealized), segregating those gains or losses included in earnings (or changes in net assets), and gains or losses recognized in other comprehensive income and a description of where those gains or losses included in earnings (or changes in net assets) are reported in the statement of income (or activities); (2) purchases, sales, issuances, and settlements (each type disclosed separately); and (3) transfers in and transfers out of Level 3 (for example, transfers due to changes in the observability of significant inputs) by class of liability.

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