| Schedule of Segment Reporting Information, by Segment [Table Text Block] |   |  |  |  |  |  |  |  |  |  |  |   |  |  |  |  |  |  |  |  |  |  |   |  |  |  |  |  |  |  |  |  |  |  |  |  |   |  |  | $ | 271,116 |  |  | $ | 295,949 |  |  | $ | 339,271 |  |   |  |  |  | 339,942 |  |  |  | 341,886 |  |  |  | 344,025 |  |   | Inventory profit elimination (2) |  |  | (33,649 | ) |  |  | (31,858 | ) |  |  | (28,862 | ) |   |  |  | $ | 577,409 |  |  | $ | 605,977 |  |  | $ | 654,434 |  |  | 
| Schedule of Segment Reporting Information, by Segment [Table Text Block] |   |  |  |  |  |  |  |  |  |  |  |   |  |  |  |  |  |  |  |  |  |  |  |  |  |   |  |  | $ | 491,467 |  |  | $ | 469,384 |  |  | $ | 453,607 |  |   |  |  |  | 626,511 |  |  |  | 579,713 |  |  |  | 580,739 |  |   | Elimination of inter-company sales |  |  | (323,776 | ) |  |  | (294,497 | ) |  |  | (287,687 | ) |   |  |  | $ | 794,202 |  |  | $ | 754,600 |  |  | $ | 746,659 |  |   |  |  |  |  |  |  |  |  |  |  |  |  |  |   |  |  |  |  |  |  |  |  |  |  |  |  |  |   |  |  | $ | 74,412 |  |  | $ | 66,988 |  |  | $ | 57,816 |  |   |  |  |  | 16,450 |  |  |  | 1,726 |  |  |  | 10,515 |  |   | Adjustment of inter-company profit (1) |  |  | (1,683 | ) |  |  | (2,780 | ) |  |  | 1,305 |  |   |  |  | $ | 89,179 |  |  | $ | 65,934 |  |  | $ | 69,636 |  |   |  |  |  |  |  |  |  |  |  |  |  |  |  |   | Depreciation & Amortization: |  |  |  |  |  |  |  |  |  |  |  |  |   |  |  | $ | 7,587 |  |  | $ | 8,044 |  |  | $ | 7,887 |  |   |  |  |  | 11,766 |  |  |  | 11,098 |  |  |  | 10,043 |  |   |  |  | $ | 19,353 |  |  | $ | 19,142 |  |  | $ | 17,930 |  |   |  |  |  |  |  |  |  |  |  |  |  |  |  |   |  |  |  |  |  |  |  |  |  |  |  |  |  |   |  |  | $ | 12,446 |  |  | $ | 9,427 |  |  | $ | 11,013 |  |   |  |  |  | 10,521 |  |  |  | 10,360 |  |  |  | 8,292 |  |   |  |  |  | 165 |  |  |  | 1,991 |  |  |  | - |  |   |  |  | $ | 23,132 |  |  | $ | 21,778 |  |  | $ | 19,305 |  |  |