Marketable Securities, Available-for-sale (Tables)

9 Months Ended

Sep. 30, 2013

Marketable Securities, Available-for-sale

Fair value of the available-for-sale marketable securities, by type of security

	SEPTEMBER 30, 2013
(in thousands)	AMORTIZED COST		GROSS UNREALIZED GAINS		GROSS UNREALIZED LOSSES			ESTIMATED FAIR VALUE
Type of security:
U.S. Treasury securities	$	93,544	$	150	$	-		$	93,694
Obligations of U.S. government agencies	20,212		16		(2		)	20,226
Municipal debt securities	37,300		675		(946		)	37,029
Corporate debt securities	164,827		81		(53		)	164,855
Asset-backed securities	24,636		74		(25		)	24,685
Total debt securities	340,519		996		(1,026		)	340,489
Time deposits	1,804		-		-			1,804
Short-term pooled investments	25,226		2		-			25,228
Total marketable securities, available-for-sale	$	367,549	$	998	$	(1,026	)	$	367,521
	DECEMBER 31, 2012
Type of security:
U.S. Treasury securities	$	3,098	$	1	$	-		$	3,099
Obligations of U.S. government agencies	133,029		112		(31		)	133,110
Municipal debt securities	21,745		896		(458		)	22,183
Corporate debt securities	163,352		116		(75		)	163,393
Asset-backed securities	27,325		153		(164		)	27,314
Total debt securities	348,549		1,278		(728		)	349,099
Short-term pooled investments	36,533		-		(7		)	36,526
Total marketable securities, available-for-sale	$	385,082	$	1,278	$	(735	)	$	385,625

Fair value of the available-for-sale marketable securities, by contractual maturity

(in thousands)	SEPTEMBER 30, 2013			DECEMBER 31, 2012
Contractual maturity:
Maturing in one year or less		$	130,674	$	66,546
Maturing after one year through three years		184,022		257,595
Maturing after three years		25,793		24,958
Total debt securities		340,489		349,099
Time deposits and short-term pooled investments		27,032		36,526
Total marketable securities, available-for-sale		$	367,521	$	385,625