Cash and Cash Equivalents and Investments in Marketable Securities

Our investment portfolio at September 30, 2012 consisted of cash, cash equivalents and investments in debt securities primarily issued by government and municipal entities.

We invest in highly-rated marketable debt securities, primarily issued by government and municipal entities that have maturities at the date of purchase of greater than three months. We also invest in other marketable debt securities with the maximum maturity or put date of any individual issue generally not greater than two years from the date of purchase, which are usually held until maturity. All of these instruments are classified as available-for-sale. As a result, they are reported at fair value using quoted market prices. Interest income is recorded as earned. Unrealized gains and losses, net of related income taxes, are reported as a component of accumulated other comprehensive income. Upon sale, realized gains and losses on the sale of marketable securities are computed based on the specific identification of the underlying cost of the securities sold and the unrealized gains and losses previously reported in other comprehensive income are reclassified to current earnings.

The following is a summary of our available-for-sale securities:



	Amortized Cost		Gross Unrealized Gain		Gross Unrealized Loss			Fair Value (Net Carrying Amount)
	(In thousands)
September 30, 2012
Marketable debt securities (state and political subdivisions)	$	285,915	$	26	$	(13	)	$	285,928

December 31, 2011
Marketable debt securities (state and political subdivisions)	$	260,879	$	74	$	—		$	260,953
Equity securities	610		143		—			753
Total marketable securities	$	261,489	$	217	$	—		$	261,706

For the nine months ended September 30, 2012, we invested $236.3 million in marketable debt securities and received a total of $212.2 million from sales and maturities of equity and marketable debt securities.