Annual report pursuant to Section 13 and 15(d)

Fair Value Measurements (Tables)

v3.8.0.1
Fair Value Measurements (Tables)
12 Months Ended
Dec. 31, 2017
Fair Value Disclosures [Abstract]  
Available-for-sale Securities [Table Text Block]
 
December 31, 2017
 
December 31, 2016
 
Adjusted Cost
 
Gross Unrealized Gains/Losses
 
Fair Value
 
Adjusted Cost
 
Gross Unrealized Gains/Losses
 
Fair Value
Municipal bonds and notes
$
13,320

 
$
(1
)
 
$
13,319

 
$
43,490

 
$

 
$
43,490

Corporate debt securities
49,432

 
(24
)
 
49,408

 
1,673

 
(2
)
 
1,671

Financial institution instruments
10,881

 

 
10,881

 
28,307

 

 
28,307

Total available-for-sale investments
$
73,633

 
$
(25
)
 
$
73,608

 
$
73,470

 
$
(2
)
 
$
73,468