Supplemental Cash Flow Information (Details) - USD ($) |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
|
| Supplemental Cash Flow Information [Abstract] | |||
| Cash paid for state income taxes | $ 223,000 | $ 211,000 | $ 172,000 |
| Foreign withholding taxes | $ 14,776,000 | $ 4,421,000 | $ 5,159,000 |