Quarterly report pursuant to Section 13 or 15(d)

Long-Term Debt - Swaps (Details)

v3.8.0.1
Long-Term Debt - Swaps (Details)
$ in Thousands
 3 Months Ended
Feb. 20, 2015
USD ($)
contract
Mar. 31, 2018
USD ($)
item
Mar. 31, 2017
USD ($)
Dec. 31, 2017
USD ($)
Derivative [Line Items]        
Number of interest rate swap agreements | contract 3      
Inventories - truck chassis floor plan   $ 4,555   $ 7,711
Bailment pool        
Derivative [Line Items]        
Bailment Pool Chasis Inventories Net   15,805   17,447
Interest Expense, Debt   29 $ 92  
Senior credit facilities | Floor plan        
Derivative [Line Items]        
Maximum borrowing capacity   20,000    
Inventories - truck chassis floor plan   4,555   7,711
Interest Expense, Debt   $ 52 $ 30  
Senior credit facilities | London Interbank Offered Rate (LIBOR) | Floor plan        
Derivative [Line Items]        
Interest rate margin (as a percent)   1.75%    
Minimum | Prime | Bailment pool        
Derivative [Line Items]        
Interest rate margin (as a percent)   0.00%    
Maximum | Prime | Bailment pool        
Derivative [Line Items]        
Interest rate margin (as a percent)   8.00%    
Interest rate swap        
Derivative [Line Items]        
Negative fair value   $ 1,191   2,178
Number of financial institutions for which the entity is exposed to counterparty credit risk | item   1    
Interest rate swap | Accrued Expenses and Other Current Liabilities        
Derivative [Line Items]        
Negative fair value   $ 506   597
Interest rate swap | Other Noncurrent Liabilities        
Derivative [Line Items]        
Negative fair value   $ 685   $ 1,581
Interest Rate Swap Effective 31 December 2015 through 29 March 2018        
Derivative [Line Items]        
Notional amount $ 45,000      
Interest rate   6.105%    
Interest Rate Swap Effective 31 December 2015 through 29 March 2018 | London Interbank Offered Rate (LIBOR)        
Derivative [Line Items]        
Interest rate added to variable rate (as a percent)   3.00%    
LIBOR floor (as a percent)   1.00%    
Interest Rate Swap Effective 29 March 2018 through 31 March 2020        
Derivative [Line Items]        
Notional amount 90,000      
Interest rate   6.916%    
Interest Rate Swap Effective 29 March 2018 through 31 March 2020 | London Interbank Offered Rate (LIBOR)        
Derivative [Line Items]        
Interest rate added to variable rate (as a percent)   3.00%    
LIBOR floor (as a percent)   1.00%    
Interest Rate Swap Effective 31 March 2020 through 30 June 2021        
Derivative [Line Items]        
Notional amount $ 135,000      
Interest rate   7.168%    
Interest Rate Swap Effective 31 March 2020 through 30 June 2021 | London Interbank Offered Rate (LIBOR)        
Derivative [Line Items]        
Interest rate added to variable rate (as a percent)   3.00%    
LIBOR floor (as a percent)   1.00%