Marketable Securities (Tables)

3 Months Ended

Mar. 31, 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)		March 31, 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		$	7,368	$	7,315	$	6,238	$	6,222
with unrecognized losses for more than 12 months		101		100		102		100
with unrecognized gains		296		296		2,088		2,089
Total Certificates of deposit	Level 1	7,765		7,711		8,428		8,411
U.S. Treasury and agency notes
with unrecognized losses for less than 12 months		29,940		29,757		29,741		29,669
with unrecognized losses for more than 12 months		136		135		137		135
with unrecognized gains		2		3		152		153
Total U.S. Treasury and agency notes	Level 2	30,078		29,895		30,030		29,957
Corporate notes
with unrecognized losses for less than 12 months		22,624		22,425		18,230		18,159
with unrecognized losses for more than 12 months		2,535		2,511		2,804		2,788
with unrecognized gains		—		—		—		—
Total Corporate notes	Level 2	25,159		24,936		21,034		20,947
Municipal notes
with unrecognized losses for less than 12 months		7,401		7,372		10,298		10,288
with unrecognized losses for more than 12 months		1,054		1,041		999		987
with unrecognized gains		152		154		277		278
Total Municipal notes	Level 2	8,607		8,567		11,574		11,553
		$	71,609	$	71,109	$	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:

	March 31, 2018
($ in thousands)	2018		2019		2020		2021		Total
Certificates of deposit	$	3,647	$	2,311	$	1,799	$	—	$	7,757
U.S. Treasury and agency notes	6,176		14,849		9,174		—		30,199
Corporate notes	9,482		7,985		7,150		400		25,017
Municipal notes	1,443		5,157		2,000		—		8,600
	$	20,748	$	30,302	$	20,123	$	400	$	71,573

	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