Quarterly report pursuant to Section 13 or 15(d)

Summary of Significant Accounting Policies - Additional Information (Details)

v3.10.0.1
Summary of Significant Accounting Policies - Additional Information (Details) - USD ($)
$ in Thousands
3 Months Ended 9 Months Ended
Sep. 30, 2018
Sep. 30, 2017
Sep. 30, 2018
Sep. 30, 2017
Jan. 01, 2018
Dec. 31, 2017
Schedule of Equity Method Investments [Line Items]            
Contract work in process     $ 4,700      
Contract assets         $ 2,082  
Percentage of dealership that is accounted for under the equity method 50.00%   50.00%     50.00%
Effective tax rate from continuing operations 32.40% 41.70% 31.10% 41.00%    
Discrete charge for non-deductible executive compensation, transition costs $ 800   $ 800      
Tax expense for uncertain tax positions     200      
Discrete charge for non-deductible disposition     600      
Discrete benefit related to vested or exercised stock compensation     900      
Discrete charge related to non-deductible asset impairment charge   $ 400   $ 400    
Income benefit $ (7,331) $ (14,126) $ (13,711) (22,254)    
Minimum            
Schedule of Equity Method Investments [Line Items]            
Expected annual effective tax rate in future periods     26.00%      
Maximum            
Schedule of Equity Method Investments [Line Items]            
Expected annual effective tax rate in future periods     28.00%      
Dealership            
Schedule of Equity Method Investments [Line Items]            
Percentage of dealership that is accounted for under the equity method 50.00%   50.00%      
ASU 2014-09 | Finance, insurance and other, net            
Schedule of Equity Method Investments [Line Items]            
Contract assets $ 8,000   $ 8,000      
ASU 2016-09            
Schedule of Equity Method Investments [Line Items]            
Income benefit       $ 500