Note 20 - Segment Information (Details) - Summary of Business by Segment - USD ($) $ in Thousands |
3 Months Ended | 12 Months Ended | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2015 |
Sep. 30, 2015 |
Jun. 30, 2015 |
Mar. 31, 2015 |
Dec. 31, 2014 |
Sep. 30, 2014 |
Jun. 30, 2014 |
Mar. 31, 2014 |
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
|
| Revenues: | |||||||||||
| Revenues | $ 299,611 | $ 341,838 | $ 444,919 | ||||||||
| Segment gross profit: | |||||||||||
| Segment gross margins | $ 29,513 | $ 8,675 | $ 5,544 | $ 13,314 | $ 28,921 | $ 20,872 | $ 6,578 | $ 9,602 | 57,046 | 65,973 | 100,165 |
| Income before interest and taxes | 46,971 | 56,128 | 90,254 | ||||||||
| Interest and other income | 5,213 | 6,877 | 5,875 | ||||||||
| Interest and other expense | (315) | 4,340 | 1,222 | ||||||||
| Provision for income taxes | (5,448) | (14,145) | (23,317) | ||||||||
| Net income | $ 29,647 | $ 4,850 | $ 3,793 | $ 8,131 | $ 30,128 | $ 11,451 | $ 5,347 | $ 6,274 | 46,421 | 53,200 | 74,034 |
| Operating Segments [Member] | Chemicals [Member] | |||||||||||
| Revenues: | |||||||||||
| Revenues | 125,848 | 146,146 | 161,501 | ||||||||
| Segment gross profit: | |||||||||||
| Segment gross margins | 35,452 | 46,062 | 54,708 | ||||||||
| Operating Segments [Member] | Biofuels [Member] | |||||||||||
| Revenues: | |||||||||||
| Revenues | 173,763 | 195,692 | 283,418 | ||||||||
| Segment gross profit: | |||||||||||
| Segment gross margins | 21,594 | 19,911 | 45,457 | ||||||||
| Operating Segments [Member] | Custom Chemicals [Member] | Chemicals [Member] | |||||||||||
| Revenues: | |||||||||||
| Revenues | 108,160 | 127,956 | 147,095 | ||||||||
| Operating Segments [Member] | Performance Chemicals [Member] | Chemicals [Member] | |||||||||||
| Revenues: | |||||||||||
| Revenues | 17,688 | 18,190 | 14,406 | ||||||||
| Corporate, Non-Segment [Member] | |||||||||||
| Segment gross profit: | |||||||||||
| Corporate expenses | $ 10,075 | $ 9,845 | $ 9,911 | ||||||||