Marketable Securities (Tables)

9 Months Ended

Sep. 30, 2018

Investments, Debt and Equity Securities [Abstract]

Summary of available-for-sale securities

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

($ in thousands)		September 30, 2018				December 31, 2017
Marketable Securities:	Fair Value Hierarchy	Cost		Fair Value		Cost		Fair Value
Certificates of deposit
with unrecognized losses for less than 12 months		$	5,237	$	5,183	$	6,238	$	6,222
with unrecognized losses for more than 12 months		1,087		1,085		102		100
with unrecognized gains		—		—		2,088		2,089
Total Certificates of deposit	Level 1	6,324		6,268		8,428		8,411
U.S. Treasury and agency notes
with unrecognized losses for less than 12 months		29,766		29,528		29,741		29,669
with unrecognized losses for more than 12 months		234		233		137		135
with unrecognized gains		3		4		152		153
Total U.S. Treasury and agency notes	Level 2	30,003		29,765		30,030		29,957
Corporate notes
with unrecognized losses for less than 12 months		21,453		21,304		18,230		18,159
with unrecognized losses for more than 12 months		3,063		3,047		2,804		2,788
with unrecognized gains		1,125		1,125		—		—
Total Corporate notes	Level 2	25,641		25,476		21,034		20,947
Municipal notes
with unrecognized losses for less than 12 months		6,770		6,717		10,298		10,288
with unrecognized losses for more than 12 months		1,074		1,065		999		987
with unrecognized gains		90		90		277		278
Total Municipal notes	Level 2	7,934		7,872		11,574		11,553
		$	69,902	$	69,381	$	71,066	$	70,868

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

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

	September 30, 2018
($ in thousands)	2018		2019		2020		2021		Total
Certificates of deposit	$	2,211	$	2,311	$	1,799	$	—	$	6,321
U.S. Treasury and agency notes	3,351		17,574		9,174		—		30,099
Corporate notes	4,325		13,721		7,150		400		25,596
Municipal notes	823		5,111		2,000		—		7,934
	$	10,710	$	38,717	$	20,123	$	400	$	69,950

	December 31, 2017
($ in thousands)	2018		2019		2020		2021		Total
Certificates of deposit	$	4,306	$	2,311	$	1,799	—		$	8,416
U.S. Treasury and agency notes	6,399		14,599		9,171		—		30,169
Corporate notes	7,954		6,430		6,450		—		20,834
Municipal notes	1,568		6,957		3,003		—		11,528
	$	20,227	$	30,297	$	20,423	$	—	$	70,947