Note B - Summary of Significant Accounting Policies (Details Textual) - USD ($) |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
|
| Trading Securities | $ 50,400,000 | $ 10,100,000 | |
| Trading Securities, Accumulated Loss | (50,000) | (6,000) | |
| Asset Impairment Charges | 0 | 0 | $ 0 |
| Unrecognized Tax Benefits | $ 0 | 0 | |
| Unamortized Debt Issuance Expense | $ 1,100,000 | ||
| Minimum [Member] | |||
| Property, Plant and Equipment, Useful Life | 3 years | ||
| Maximum [Member] | |||
| Property, Plant and Equipment, Useful Life | 15 years | ||