Marketable Securities (Tables)

9 Months Ended

Sep. 30, 2012

Marketable Securities [Abstract]

Schedule of Marketable Securities

All marketable securities were classified as held-to-maturity for the dates presented and the carrying amounts of held-to-maturity securities were as follows:

(in thousands)	September 30, 2012		December 31, 2011		September 30, 2011
U.S. Government and agency obligations	$	15,062	$	40,240	$	40,218
Commercial paper	19,976		24,980		29,978
Municipal bonds	7,082		2,057		4,036
Corporate bonds	5,065		3,131		3,157
Total short-term marketable securities	47,185		70,408		77,389
U.S. Government and agency obligations	36,103		65,109		45,268
Municipal bonds	1,699		8,909		8,952
Corporate bonds	—		5,232		5,289
Total long-term marketable securities	37,802		79,250		59,509
Total marketable securities	$	84,987	$	149,658	$	136,898

Held-to-maturity Securities

Scheduled maturities of held-to-maturity investments were as follows (in thousands):

September 30, 2012
Due within one year	$	47,185
Due in one to five years	37,802
Total	$	84,987