Marketable Securities (Tables)

9 Months Ended

Sep. 30, 2012

Investments, Debt and Equity Securities [Abstract]

Summary of available-for-sale securities

The following is a summary of available-for-sale securities at September 30, 2012 and December 31, 2011:

($ in thousands)		2012				2011
Marketable Securities:	Fair Value Hierarchy	Cost		Estimated Fair Value		Cost		Estimated Fair Value
Certificates of deposit
with unrecognized losses for less than 12 months		$	711	$	707	$	3,646	$	3,605
with unrecognized gains		5,963		6,017		3,525		3,551
Total Certificates of deposit	Level 1	6,674		6,724		7,171		7,156
US Treasury and agency notes
with unrecognized losses for less than 12 months		3,925		3,888		4,352		4,338
with unrecognized losses for more than 12 months		—		—		1,002		1,000
with unrecognized gains		15,220		15,348		16,479		16,660
Total US Treasury and agency notes	Level 2	19,145		19,236		21,833		21,998
Corporate notes
with unrecognized losses for less than 12 months		1,077		1,069		9,230		9,098
with unrecognized losses for more than 12 months		—		—		1,539		1,494
with unrecognized gains		30,334		30,858		19,369		19,738
Total Corporate notes	Level 2	31,411		31,927		30,138		30,330
Municipal notes
with unrecognized losses for less than 12 months		1,291		1,277		1,177		1,165
with unrecognized losses for more than 12 months		865		861		881		873
with unrecognized gains		7,704		7,811		6,964		7,044
Total Municipal notes	Level 2	9,860		9,949		9,022		9,082
		$	67,090	$	67,836	$	68,164	$	68,566

Summary of maturities, at par, of marketable securities

The following tables summarize the maturities, at par, of marketable securities by year:

(in thousands)
At September 30, 2012	2012		2013		2014		2015		2016		Total
Certificates of deposit	$	249	$	1,255	$	1,627	$	3,059	$	301	$	6,491
U.S. Treasury and agency notes	287		7,785		8,482		2,633		—		19,187
Corporate notes	895		11,416		7,029		8,920		2,113		30,373
Municipal notes	535		2,305		4,340		1,960		400		9,540
	$	1,966	$	22,761	$	21,478	$	16,572	$	2,814	$	65,591

(in thousands)
At December 31, 2011	2012		2013		2014		2015		2016		Total
Certificates of deposit	$	1,536	$	1,255	$	1,627	$	2,526	$	—	$	6,944
U.S. Treasury and agency notes	4,734		10,285		5,856		936		—		21,811
Corporate notes	3,450		11,231		8,923		5,584		—		29,188
Municipal notes	860		2,505		4,145		1,160		—		8,670
	$	10,580	$	25,276	$	20,551	$	10,206	$	—	$	66,613