Short- and Long-Term Investments and Investments on Deposit for Licensure

6 Months Ended

Jun. 30, 2011

Short- and Long-Term Investments and Investments on Deposit for Licensure [Abstract]

Short- and Long-Term Investments and Investments on Deposit for Licensure

5.  Short- and Long-Term Investments and Investments on Deposit for Licensure

The amortized cost, gross unrealized holding gains, gross unrealized holding losses and fair value for available-for-sale short- and long-term investments and investments on deposit for licensure held at June 30, 2011 were as follows:

			Gross		Gross
	Amortized		Unrealized		Unrealized		Fair
	Cost		Holding Gains		Holding Losses		Value
Auction rate securities	$	16,750	$	—	$	1,078	$	15,672
Certificates of deposit		7,002		—		—		7,002
Commercial paper		51,268		—		6		51,262
Corporate bonds		343,337		2,917		75		346,179
Debt securities of government sponsored entities		374,866		776		198		375,444
Equity index funds		15,888		329		—		16,217
Federally insured corporate bonds		21,045		185		—		21,230
Money market funds		23,791		—		—		23,791
Municipal bonds		355,121		7,065		431		361,755
U.S. Treasury securities		34,393		105		—		34,498
Total	$	1,243,461	$	11,377	$	1,788	$	1,253,050

The amortized cost, gross unrealized holding gains, gross unrealized holding losses and fair value for available-for-sale short- and long-term investments and investments on deposit for licensure held at December 31, 2010 were as follows:

			Gross		Gross
	Amortized		Unrealized		Unrealized		Fair
	Cost		Holding Gains		Holding Losses		Value
Auction rate securities	$	22,650	$	—	$	1,357	$	21,293
Certificates of deposit		13,651		—		—		13,651
Commercial paper		14,797		—		4		14,793
Corporate bonds		235,775		2,327		186		237,916
Debt securities of government sponsored entities		331,893		623		465		332,051
Federally insured corporate bonds		21,097		360		3		21,454
Money market funds		20,315		—		—		20,315
Municipal bonds		301,234		1,145		1,562		300,817
U.S. Treasury securities		21,592		130		1		21,721
Total	$	983,004	$	4,585	$	3,578	$	984,011

The amortized cost and fair value of investments in debt securities, by contractual maturity, for available-for-sale short- and long-term investments and investments on deposit for licensure held at June 30, 2011 were as follows:

	Amortized		Fair
	Cost		Value
Maturing within one year	$	464,912	$	465,751
Maturing between one year and five years		515,855		519,137
Maturing between five years and ten years		178,643		183,639
Maturing in greater than ten years		68,163		68,306
Total	$	1,227,573	$	1,236,833

Investments in equity index funds with a cost of $15,888 and a fair value of $16,217 are excluded from the table above because they do not have contractual maturities.

For the three and six months ended June 30, 2011 and 2010, the net unrealized gain recorded to accumulated other comprehensive income as a result of changes in fair value for investments classified as available-for-sale were as follows:

	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2011		2010		2011		2010
Net unrealized gain recorded to accumulated other comprehensive income	$	9,546	$	972	$	8,583	$	1,445

The following table shows the fair value of the Company’s available-for-sale investments with unrealized losses that are not deemed to be other-than-temporarily impaired at June 30, 2011 and December 31, 2010. Investments are aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position:

	Less than 12 Months						12 Months or Greater
			Gross		Total				Gross		Total
	Fair		Unrealized		Number of		Fair		Unrealized		Number of
	Value		Holding Losses		Securities		Value		Holding Losses		Securities
June 30, 2011:
Auction rate securities	$	—	$	—		—	$	15,672	$	1,078		4
Commercial paper		17,985		6		1		—		—		—
Corporate bonds		50,231		70		22		8,983		5		1
Debt securities of government sponsored entities		71,396		198		18		—		—		—
Municipal bonds		45,002		328		13		1,912		103		1
Total temporarily impaired securities	$	184,614	$	602		54	$	26,567	$	1,186		6

	Less than 12 Months						12 Months or Greater
			Gross		Total				Gross		Total
	Fair		Unrealized		Number of		Fair		Unrealized		Number of
	Value		Holding Losses		Securities		Value		Holding Losses		Securities
December 31, 2010:
Auction rate securities	$	—	$	—		—	$	21,293	$	1,357		6
Commercial paper		19,495		4		8		—		—		—
Corporate bonds		71,278		186		37		—		—		—
Debt securities of government sponsored entities		86,881		465		29		—		—		—
Federally insured corporate bond		4,036		3		1		—		—		—
Municipal bonds		160,860		1,562		64		—		—		—
U.S. Treasury securities		9,564		1		3		—		—		—
Total temporarily impaired securities	$	352,114	$	2,221		142	$	21,293	$	1,357		6

The Company typically invests in highly-rated debt securities and its policy generally limits the amount of credit exposure to any one issuer. The Company’s investment policy requires investments to generally be investment grade, primarily rated single-A or better, with the objective of minimizing the potential risk of principal loss and maintaining appropriate liquidity for the Company’s operations. Fair values were determined for each individual security in the investment portfolio. When evaluating investments for other-than-temporary impairment, the Company reviews factors such as the length of time and extent to which fair value has been below cost basis, the financial condition of the issuer and the Company’s intent to sell, or whether it is more likely than not that the Company will be required to sell the investment before recovery of the investment’s amortized cost basis. During the three and six month periods ended June 30, 2011 the Company did not record any charges for other-than-temporary impairment of its available-for-sale securities.

As of June 30, 2011, the Company’s investments in debt securities in an unrealized loss position all hold investment grade ratings by various credit rating agencies. Additionally, the issuers have been current on all interest payments. The temporary declines in value at June 30, 2011 are primarily due to fluctuations in short-term market interest rates and the lack of liquidity of auction rate securities. Auction rate securities that have been in an unrealized loss position for greater than 12 months have experienced losses due to the lack of liquidity for these instruments, not as a result of impairment of the underlying debt securities. The Company does not intend to sell these securities prior to maturity or recovery and it is not likely that the Company will be required to sell these securities prior to maturity; therefore, there is no indication of other-than-temporary impairment for these securities.