Cash, Cash Equivalents and Marketable Securities (Tables)

3 Months Ended

Mar. 31, 2012

Cash, Cash Equivalents and Marketable Securities [Abstract]

Summary of cash and investments in cash equivalents and marketable securities

The following table summarizes our investments in cash equivalents and marketable securities held by investment managers and overnight investments:

	March 31,			December 31,
	2012			2011
	(in thousands)
Overnight Holdings
Money market funds (cash equivalents)	$	87,470		$	71,350
Investment Holdings
Money market funds (cash equivalents)		59,372			59,587
Marketable securities		56,981			56,987
		203,823			187,924
Cash held in demand accounts		102,157			113,968
Outstanding checks		(14,451	)		(33,697	)
Total cash, cash equivalents and marketable securities	$	291,529		$	268,195
Cash and cash equivalents	$	234,548		$	211,208
Marketable securities		56,981			56,987
	$	291,529		$	268,195

Summary of fair value measurements of financial assets

The following table summarizes the levels of fair value measurements of our financial assets:

	Fair Value Measurements
	(in thousands)
	March 31,
	2012		Level 1		Level 2		Level 3
Money market funds	$	146,842	$	146,842	$	-	$	-
Municipal bonds		56,981		-		56,981		-
Total	$	203,823	$	146,842	$	56,981	$	-

	Fair Value Measurements
	(in thousands)
	December 31,
	2011		Level 1		Level 2		Level 3
Money market funds	$	130,937	$	130,937		-	$	-
Municipal bonds		56,987		-		56,987		-
Total	$	187,924	$	130,937	$	56,987	$	-

Summary of available-for-sale securities

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

			Gross		Gross
	Amortized		Unrealized		Unrealized			Estimated
	Cost		Gains		Losses			Fair Value
			(in thousands)
March 31, 2012:
Municipal bonds	$	56,882	$	117	$	(18	)	$	56,981
December 31, 2011:
Municipal bonds	$	56,945	$	90	$	(48	)	$	56,987

Contractual maturities of marketable securities

As of March 31, 2012, the contractual maturities of our marketable securities were as follows:

	Amortized Cost		Estimated Fair Value
	(in thousands)
Less than one year	$	33,566	$	33,576
One to five years		23,316		23,405
Total	$	56,882	$	56,981