5. Income Taxes (Details - Reconciliation) - USD ($) $ in Thousands |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
|
| Income Tax Disclosure [Abstract] | |||
| Income tax expense at the statutory federal income tax rate | $ 14,304 | $ 14,707 | $ 13,743 |
| Increase (decrease) resulting from: | |||
| State income taxes | 882 | 934 | 770 |
| Section 199 manufacturing deduction | (1,383) | (1,290) | (1,307) |
| R&D tax credits | (2,254) | (393) | (626) |
| Other, net | 396 | 255 | 103 |
| Total income tax expense | $ 11,945 | $ 14,213 | $ 12,683 |