Investments (Tables)
|
9 Months Ended |
Sep. 30, 2018 |
|---|
| Available For Sale Securities |
|
| Gain (Loss) on Investments [Line Items] |
|
| Summary of the cost and fair value of investments |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Gross Unrealized
|
|
Fair
|
|
|
|
Cost
|
|
Gains
|
|
(Losses)
|
|
Value
|
|
As of September 30, 2018
|
|
$
|
595
|
|
$
|
129
|
|
$
|
—
|
|
$
|
724
|
|
As of December 31, 2017
|
|
|
595
|
|
|
82
|
|
|
—
|
|
|
677
|
|
| Trading Securities. |
|
| Gain (Loss) on Investments [Line Items] |
|
| Cost and fair value of investments |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Gross Unrealized
|
|
Fair
|
|
|
|
Cost
|
|
Gains
|
|
(Losses)
|
|
Value
|
|
As of September 30, 2018
|
|
$
|
12,921
|
|
$
|
1,150
|
|
$
|
(238)
|
|
$
|
13,833
|
|
As of December 31, 2017
|
|
|
9,978
|
|
|
950
|
|
|
(269)
|
|
|
10,659
|
|
| Summary of proceeds and realized gains and losses |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Sale
|
|
Realized
|
|
|
|
Proceeds
|
|
Gains
|
|
(Losses)
|
|
For the Three Months Ended September 30, 2018
|
|
$
|
16
|
|
$
|
2
|
|
$
|
—
|
|
For the Three Months Ended September 30, 2017
|
|
|
2,954
|
|
|
84
|
|
|
(11)
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Sale
|
|
Realized
|
|
|
|
Proceeds
|
|
Gains
|
|
(Losses)
|
|
For the Nine Months Ended September 30, 2018
|
|
$
|
644
|
|
$
|
34
|
|
$
|
(5)
|
|
For the Nine Months Ended September 30, 2017
|
|
|
4,166
|
|
|
111
|
|
|
(26)
|
|