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 September 30, 2012 were as follows (dollars in thousands):



	Amortized Cost		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses		Fair Value
Certificates of deposit	$	13,024	$	—	$	—	$	13,024
Commercial paper	61,301		132		—		61,433
Corporate bonds	594,446		5,086		27		599,505
Debt securities of government sponsored entities	145,538		625		6		146,157
Equity index funds	66,562		6,217		104		72,675
Money market funds	87,752		—		—		87,752
Municipal bonds	478,955		20,123		355		498,723
U.S. Treasury securities	14,746		64		—		14,810
Total	$	1,462,324	$	32,247	$	492	$	1,494,079

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, 2011 were as follows (dollars in thousands):



	Amortized Cost		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses		Fair Value
Certificates of deposit	$	118,081	$	13	$	—	$	118,094
Commercial paper	172,657		2		95		172,564
Corporate bonds	565,382		2,852		1,510		566,724
Debt securities of government sponsored entities	289,901		742		100		290,543
Equity index funds	40,146		1,355		658		40,843
Money market funds	15,067		—		—		15,067
Municipal bonds	394,599		16,978		1,000		410,577
U.S. Treasury securities	26,045		80		1		26,124
Total	$	1,621,878	$	22,022	$	3,364	$	1,640,536

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 September 30, 2012 were as follows (dollars in thousands):



	Amortized Cost		Fair Value
Maturing within one year	$	505,042	$	506,170
Maturing between one year and five years	570,644		578,694
Maturing between five years and ten years	238,334		252,493
Maturing in greater than ten years	81,742		84,047
Total	$	1,395,762	$	1,421,404

Investments in equity index funds with a cost of $66.6 million and a fair value of $72.7 million are excluded from the table above because they are not debt securities.

The following tables show 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 September 30, 2012 and December 31, 2011. Investments are aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position (dollars in thousands):



	Less than 12 Months					12 Months or Greater
	Fair Value		Gross Unrealized Holding Losses		Total Number of Securities	Fair Value		Gross Unrealized Holding Losses		Total Number of Securities
September 30, 2012:
Corporate bonds	$	21,179	$	27	35	$	—	$	—	—
Debt securities of government sponsored entities	5,625		6		5	—		—		—
Equity index funds	4,646		104		2	—		—		—
Municipal bonds	36,852		86		16	2,556		269		1
Total temporarily impaired securities	$	68,302	$	223	58	$	2,556	$	269	1

	Less than 12 Months					12 Months or Greater
	Fair Value		Gross Unrealized Holding Losses		Total Number of Securities	Fair Value		Gross Unrealized Holding Losses		Total Number of Securities
December 31, 2011:
Commercial paper	$	149,074	$	95	12	$	—	$	—	—
Corporate bonds	185,231		1,498		98	8,989		12		1
Debt securities of government sponsored entities	103,766		100		28	—		—		—
Equity index funds	17,021		658		5	—		—		—
Municipal bonds	5,129		1		1	11,551		999		3
U.S. Treasury securities	12,025		1		3	—		—		—
Total temporarily impaired securities	$	472,246	$	2,353	147	$	20,540	$	1,011	4

The Company typically invests in highly-rated debt securities and its investment policy generally limits the amount of credit exposure to any one issuer. The Company’s investment policy requires fixed income 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, general market conditions 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 a security’s amortized cost basis. During the three and nine months ended September 30, 2012, the Company did not record any charges for other-than-temporary impairment of its available-for-sale securities.

As of September 30, 2012, 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 September 30, 2012 are primarily due to fluctuations in short-term market interest rates and the lack of liquidity of municipal bond auction rate securities. The Company believes that the auction rate security that has been in an unrealized loss position for greater than 12 months has experienced losses due to the lack of liquidity for these instruments, not as a result of impairment of the underlying debt security. The Company does not intend to sell the securities in an unrealized loss position prior to maturity or recovery and it is not likely that the Company will be required to sell these securities prior to maturity or recovery; therefore, there is no indication of other-than-temporary impairment for these securities.

Realized gains and losses on available-for-sale securities have been reclassified, on a specific identification basis, from accumulated other comprehensive income and included in investment income and other in the accompanying Condensed Consolidated Statements of Income. Realized gains and losses for the three and nine months ended September 30, 2012 and 2011 were as follows (dollars in thousands):



	Three Months Ended September 30,					Nine Months Ended September 30,
	2012			2011		2012			2011
Gross realized gains	$	236		$	84	$	2,758		$	134
Gross realized losses	(8		)	—		(60		)	(9		)
Net realized gains	$	228		$	84	$	2,698		$	125