Quarterly report pursuant to Section 13 or 15(d)

Revenue Recognition (Revenue by customer and timing recognitions) (Details)

v3.19.1
Revenue Recognition (Revenue by customer and timing recognitions) (Details)
$ in Thousands
 3 Months Ended
Mar. 31, 2019
USD ($)
item
Mar. 31, 2018
USD ($)
Dec. 31, 2018
USD ($)
Disaggregation of Revenue [Line Items]      
Retained Earnings $ 130,176   $ 136,765
Net sales 93,187 $ 83,964  
Independent dealer      
Disaggregation of Revenue [Line Items]      
Net sales 58,860 51,321  
Government      
Disaggregation of Revenue [Line Items]      
Net sales 15,529 13,821  
Fleet      
Disaggregation of Revenue [Line Items]      
Net sales 14,952 14,352  
Other      
Disaggregation of Revenue [Line Items]      
Net sales 3,846 4,470  
Point in time      
Disaggregation of Revenue [Line Items]      
Net sales 67,840 60,627  
Over time      
Disaggregation of Revenue [Line Items]      
Net sales $ 25,347 23,337  
Work Truck Attachments      
Disaggregation of Revenue [Line Items]      
Number of revenue streams | item 2    
Net sales $ 25,817 24,596  
Work Truck Attachments | Independent dealer      
Disaggregation of Revenue [Line Items]      
Net sales 25,817 24,596  
Work Truck Attachments | Point in time      
Disaggregation of Revenue [Line Items]      
Net sales $ 25,817 24,596  
Work Truck Solutions      
Disaggregation of Revenue [Line Items]      
Number of revenue streams | item 4    
Net sales $ 67,370 59,368  
Work Truck Solutions | Independent dealer      
Disaggregation of Revenue [Line Items]      
Net sales 33,043 26,725  
Work Truck Solutions | Government      
Disaggregation of Revenue [Line Items]      
Net sales 15,529 13,821  
Work Truck Solutions | Fleet      
Disaggregation of Revenue [Line Items]      
Net sales 14,952 14,352  
Work Truck Solutions | Other      
Disaggregation of Revenue [Line Items]      
Net sales 3,846 4,470  
Work Truck Solutions | Point in time      
Disaggregation of Revenue [Line Items]      
Net sales 42,023 36,031  
Work Truck Solutions | Over time      
Disaggregation of Revenue [Line Items]      
Net sales 25,347 23,337  
Effect of Change Higher/(Lower) | ASC 2014-09 | Work Truck Solutions | Over time      
Disaggregation of Revenue [Line Items]      
Net sales $ 145 $ 294