| In millions, except per share items | Dec-31-21 | Dec-31-20 | Dec-31-19 | Dec-31-18 | Dec-31-17 | Dec-31-16 | Dec-31-15 | Dec-31-14 |
| | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K |
| Current assets: | | | | | | | | |
| Cash and cash equivalents | | | | | | | | |
| Accounts receivable, net | 71.0 | 83.2 | 87.9 | 81.5 | 79.1 | 78.6 | 67.7 | 60.9 |
| Inventories | 104.0 | 79.5 | 77.9 | 82.0 | 71.5 | 70.9 | 51.6 | 48.2 |
| Inventories - truck chassis floor plan | 2.7 | 8.1 | 6.5 | 4.2 | 7.7 | 3.9 | | |
| Refundable income taxes paid | 1.2 | | | | | 1.5 | 4.9 | |
| Prepaid and other current assets | 4.5 | 5.3 | 3.5 | 3.6 | 2.9 | 2.9 | 2.1 | 2.2 |
| Total current assets | 220.4 | 217.2 | 211.5 | 199.1 | 198.1 | 176.4 | 169.2 | 142.5 |
| Property, plant, and equipment, net | 66.8 | 64.3 | 58.4 | 55.2 | 54.0 | 52.1 | 42.6 | 37.5 |
| Goodwill | 113.1 | 113.1 | 241.0 | 241.0 | 241.0 | 238.3 | 160.9 | 161.0 |
| Other intangible assets, net | 142.1 | 152.8 | 163.7 | 174.7 | 186.2 | 194.9 | 127.6 | 135.0 |
| Non-qualified benefit plan assets | 10.3 | 9.0 | 7.3 | | | | | |
| Other long-term assets | 1.2 | 1.3 | 1.2 | 6.2 | 5.9 | 4.5 | 2.7 | 1.9 |
| Total assets | 572.5 | 579.2 | 705.7 | 676.2 | 685.2 | 666.2 | 503.2 | 480.4 |
| |
| Current liabilities: | | | | | | | | |
| Accounts payable | 27.4 | 16.3 | 16.1 | 18.7 | 16.3 | 17.3 | 14.6 | 9.8 |
| Accrued expenses and other current liabilities | 36.1 | 30.8 | 26.5 | 23.3 | 21.0 | 27.3 | 25.5 | 33.7 |
| Floor plan obligations | 2.7 | 7.9 | 6.5 | 4.2 | 7.7 | 3.9 | | |
| Operating lease liability - current | 4.6 | 4.3 | 3.8 | | | | | |
| Income taxes payable | | 5.2 | 3.0 | 0.1 | 3.0 | | | 0.6 |
| Short term borrowings | | | | | | | 186.5 | |
| Current portion of long-term debt | 11.1 | 1.7 | 22.1 | 32.7 | 32.7 | 2.8 | 1.6 | 1.6 |
| Total current liabilities | 81.9 | 66.2 | 78.1 | 79.1 | 80.8 | 51.4 | 41.7 | 45.7 |
| Retiree benefits and deferred compensation | 17.2 | 15.8 | 14.0 | 6.2 | 6.8 | 7.2 | 6.7 | 6.8 |
| Deferred income taxes | 29.8 | 26.7 | 47.2 | 48.2 | 39.3 | 54.6 | 54.9 | 49.9 |
| Long-term debt, net | 206.1 | 236.7 | | | | | | |
| Other long-term liabilities | 7.5 | 16.2 | 12.1 | 14.9 | 17.0 | 15.7 | 6.0 | 6.0 |
| |
| Stockholders’ equity: | | | | | | | | |
| Common Stock | 0.2 | 0.2 | 0.2 | 0.2 | 0.2 | 0.2 | 0.2 | 0.2 |
| Additional paid-in capital | 163.6 | 157.8 | 155.0 | 151.8 | 147.3 | 144.5 | 141.6 | 138.3 |
| Retained earnings | 51.9 | 47.7 | 160.7 | 136.8 | 115.7 | 82.4 | 64.8 | 40.8 |
| Accumulated other comprehensive income (loss), net of tax | -1.1 | -5.5 | -2.8 | -6.0 | -6.6 | -6.7 | -6.2 | -6.0 |
| Total stockholders’ equity | 214.6 | 200.2 | 313.2 | 282.8 | 256.7 | 220.5 | 200.5 | 173.3 |
| Total liabilities and stockholders’ equity | 572.5 | 579.2 | 705.7 | 676.2 | 685.2 | 666.2 | 503.2 | 480.4 |