Note 20 - Industry Segment and Geographic Information (Details) - Reported Segments (USD $)
In Thousands, unless otherwise specified
 3 Months Ended 12 Months Ended
Dec. 31, 2013
Sep. 30, 2013
Jun. 30, 2013
Mar. 31, 2013
Dec. 31, 2012
Sep. 30, 2012
Jun. 30, 2012
Mar. 31, 2012
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Segment Reporting Information [Line Items]                      
Revenue $ 65,973 [1] $ 87,620 [1] $ 41,777 [1] $ 48,923 [1] $ 63,133 [1] $ 83,970 [1] $ 47,448 [1] $ 41,088 [1] $ 244,293 [2] $ 235,639 [3] $ 251,743 [4]
Cost of sales                 161,543 193,583 197,069
Gross profit 27,950 [1],[5] 29,420 [1],[5] 13,283 [1],[5] 12,097 [1],[5] 12,919 [1] 13,398 [1] 6,847 [1] 8,892 [1] 82,750 42,056 54,674
Selling, general and administrative expenses (including research and development)                 27,700 23,946 24,638
Charges related to U.S. Attorney investigation         3,600 4,100       7,990 545
Other (gains) and losses                 440 (2,506) (24,868)
Operating income 14,679 [1],[6] 21,921 [1],[6] 6,690 [1],[6] 4,723 [1],[6] 2,351 [1],[7] 2,904 [1],[7] 4,201 [1],[7] 3,170 [1],[7] 48,013 12,626 54,359
Depreciation and amortization                 21,056 17,999 16,430
Identifiable assets 331,394       295,296       331,394 295,296 277,830
Capital expenditures                 24,796 25,064 23,352
Animal Nutrition [Member] | Plant Closure [Member]
                      
Segment Reporting Information [Line Items]                      
Loss related to plant closure                 6,597    
Animal Nutrition [Member]
                      
Segment Reporting Information [Line Items]                      
Revenue                 213,236 [2] 213,624 [3] 236,489 [4]
Cost of sales                 136,146 176,588 187,092
Gross profit                 77,090 37,036 49,397
Selling, general and administrative expenses (including research and development)                 2,744 2,564 2,804
Charges related to U.S. Attorney investigation                   7,990 545
Other (gains) and losses                 140 (2,635) (24,869)
Operating income                 67,609 29,117 70,917
Depreciation and amortization                 17,946 15,859 15,098
Identifiable assets 277,063       266,307       277,063 266,307 248,672
Capital expenditures                 19,080 22,810 22,542
Human Nutrition [Member] | Plant Closure [Member]
                      
Segment Reporting Information [Line Items]                      
Loss related to plant closure                    [8]    
Human Nutrition [Member]
                      
Segment Reporting Information [Line Items]                      
Revenue                 31,057 [2],[8] 22,015 [3] 15,254 [4]
Cost of sales                 25,397 [8] 16,995 9,977
Gross profit                 5,660 [8] 5,020 5,277
Selling, general and administrative expenses (including research and development)                 6,959 [8] 3,795 3,286
Other (gains) and losses                 305 [8] 129 1
Operating income                 (1,604) [8] 1,096 1,990
Depreciation and amortization                 2,369 [8] 1,315 648
Identifiable assets 53,093 [8]       27,109       53,093 [8] 27,109 27,048
Capital expenditures                 5,350 [8] 1,759 566
Unallocated [Member]
                      
Segment Reporting Information [Line Items]                      
Revenue                    [2]    [3]    [4]
Selling, general and administrative expenses (including research and development)                 17,997 17,587 18,548
Other (gains) and losses                 (5)    
Operating income                 (17,992) (17,587) (18,548)
Depreciation and amortization                 741 825 684
Identifiable assets 1,238       1,880       1,238 1,880 2,110
Capital expenditures                 366 495 244
Plant Closure [Member]
                      
Segment Reporting Information [Line Items]                      
Loss related to plant closure $ 6,600               $ 6,597    
[1] Revenues, gross profit, operating income, and net income (loss) are rounded to thousands each quarter. Therefore, the sum of the quarterly amounts may not equal the annual amounts reported.
[2] Excludes revenue from internal customers of $1.3 million for fish oil that was transferred from the animal nutrition segment to the human nutrition segment at cost.
[3] Excludes revenue from internal customers of $1.6 million for fish oil that was transferred from the animal nutrition segment to the human nutrition segment at cost.
[4] Excludes revenue from internal customers of $0.4 million for fish oil that was transferred from the animal nutrition segment to the human nutrition segment at cost.
[5] Gross profit as a percentage of revenues for the quarter ended December 31, 2013 increased substantially as compared to the previous three quarters of 2013. This increase was due to greater than anticipated inventory production after September 30, 2013. As a result, standard cost for 2013 inventory, for which sales commenced largely in the third quarter of 2013, was decreased and cumulatively adjusted all previous sales of 2013 inventory production during the quarter ended December 31, 2013. The impact of the change in standard cost to the quarter ended December 31, 2013 is estimated to be approximately $4 million.
[6] Included in the quarter ended December 31, 2013 expense is a $6.6 million charge related to the loss on the plant closure.
[7] Included in the quarter ended September 30, 2012 expense is a $4.1 million charge related to the U.S. Attorney investigation. A similar additional charge of $3.6 million was recognized for the quarter ended December 31, 2012. These charges were non-deductible for federal tax purposes.
[8] Includes revenues and related expenses for WSP from February 27, 2013 through December 31, 2013.