Marketable Securities (Tables)

12 Months Ended

Dec. 31, 2012

Investments, Debt and Equity Securities [Abstract]

Summary of available-for-sale securities

The following is a summary of available-for-sale securities at December 31:

($ 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		$	1,578	$	1,571	$	3,646	$	3,605
with unrecognized losses for more than 12 months		508		507		—		—
with unrecognized gains		5,586		5,628		3,525		3,551
Total Certificates of deposit	Level 1	7,672		7,706		7,171		7,156
US Treasury and agency notes
with unrecognized losses for less than 12 months		3,057		3,024		4,352		4,338
with unrecognized losses for more than 12 months		874		873		1,002		1,000
with unrecognized gains		12,175		12,267		16,479		16,660
Total US Treasury and agency notes	Level 2	16,106		16,164		21,833		21,998
Corporate notes
with unrecognized losses for less than 12 months		1,993		1,971		9,230		9,098
with unrecognized losses for more than 12 months		201		200		1,539		1,494
with unrecognized gains		29,210		29,653		19,369		19,738
Total Corporate notes	Level 2	31,404		31,824		30,138		30,330
Municipal notes
with unrecognized losses for less than 12 months		1,961		1,948		1,177		1,165
with unrecognized losses for more than 12 months		620		613		881		873
with unrecognized gains		6,702		6,794		6,964		7,044
Total Municipal notes	Level 2	9,283		9,355		9,022		9,082
		$	64,465	$	65,049	$	68,164	$	68,566

Summary of maturities, at par, of marketable securities by year

The following tables summarize the maturities, at par, of marketable securities by year ($ in thousands):

At December 31, 2012	2013		2014		2015		2016		Total
Certificates of deposit	$	1,268	$	1,627	$	4,316	$	301	$	7,512
U.S. Treasury and agency notes	6,285		7,248		2,633		11		16,177
Corporate notes	10,916		6,729		9,420		3,325		30,390
Municipal notes	2,305		4,340		1,960		400		9,005
	$	20,774	$	19,944	$	18,329	$	4,037	$	63,084

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