Summary of Significant Accounting Policies (Details) - USD ($) |
3 Months Ended | 6 Months Ended | 12 Months Ended | ||
|---|---|---|---|---|---|
Jun. 30, 2018 |
Jun. 30, 2017 |
Jun. 30, 2018 |
Jun. 30, 2017 |
Dec. 31, 2017 |
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| Accounting Policies [Abstract] | |||||
| Realized gains (losses) recognized on available-for-sale investments | $ 100,000 | $ (100,000) | |||
| Realized gains (losses) recognized on available-for-sale investments | $ 0 | $ 0 | |||
| Reduction in deferred tax asset value and valuation allowance | $ 3,700,000 | ||||
| X | ||||||||||
- Definition Debt Securities, Available-For-Sale, Realized Gain (Loss) No definition available.
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| X | ||||||||||
- Definition Tax Cuts and Jobs Act of 2017, Incomplete Accounting, Change in Tax Rate, Income Tax Expense (Benefit), Before Valuation Allowance Impact No definition available.
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition This item represents the difference between the gross realized gains and losses realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities. Additionally, this item would include any losses recognized for other than temporary impairments (OTTI) of the subject investments in debt and equity securities. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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