Investments - Narrative (Details) - USD ($) |
3 Months Ended | 9 Months Ended | 12 Months Ended | ||
|---|---|---|---|---|---|
Sep. 30, 2017 |
Sep. 30, 2016 |
Sep. 30, 2017 |
Sep. 30, 2016 |
Dec. 31, 2016 |
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| Schedule of Available-for-sale Securities [Line Items] | |||||
| Proceeds from the sales of available-for-sale securities | $ 1,800,000 | $ 0 | |||
| Trading securities portfolio | $ 1,907,000 | 1,907,000 | $ 1,391,000 | ||
| Gains on trading securities | 66,000 | $ 43,000 | 168,000 | $ 78,000 | |
| Gross unrealized losses | (23,000) | ||||
| Securities in a loss position for more than 12 months | 0 | 0 | |||
| U.S. government security funds | |||||
| Schedule of Available-for-sale Securities [Line Items] | |||||
| Gross unrealized losses | $ 0 | $ 0 | $ (23,000) | ||
| X | ||||||||||
- Definition Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of unrealized loss on securities classified as available-for-sale that have been in a loss position for twelve months or longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The cash inflow associated with the sale of debt and equity securities classified as available-for-sale securities. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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- Definition This item represents the gain realized during the period from the sale of trading securities. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Total of all securities that are purchased with the intent to be sold in the short-term and that are pledged to one or more secured parties who have the right to buy, sell, or re-pledge the collateral. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Details
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