Quarterly report pursuant to Section 13 or 15(d)

Litigation and Related Matters (Details)

v3.10.0.1
Litigation and Related Matters (Details) - USD ($)
1 Months Ended 12 Months Ended
Jul. 18, 2018
Jun. 14, 2018
May 15, 2017
Jul. 13, 2016
May 16, 2016
Jul. 06, 2015
Jul. 31, 2015
Dec. 31, 2013
Sep. 30, 2018
Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]                    
Environmental liabilities                 $ 0 $ 0
Armstrong Kushan, multilayered wood flooring imports from China                    
Loss Contingencies [Line Items]                    
Countervailing duties rate               0.98%    
Antidumping duties rate           3.31%   0.00%    
Armstrong Kushan, multi-layered wood flooring imports from China, second administrative review                    
Loss Contingencies [Line Items]                    
Countervailing duties rate             0.99%      
Antidumping duties rate             13.74%      
Armstrong Kushan, multi-layered wood flooring imports from China, second administrative review | Accounts payable and accrued expenses                    
Loss Contingencies [Line Items]                    
Estimated litigation liability                 4,800,000  
Armstrong Kushan, multi-layered wood flooring imports from China, third administrative review                    
Loss Contingencies [Line Items]                    
Countervailing duties rate         1.38%          
Antidumping duties rate       17.37%            
Armstrong Kushan, multi-layered wood flooring imports from China, third administrative review | Accounts payable and accrued expenses                    
Loss Contingencies [Line Items]                    
Estimated litigation liability                 $ 6,000,000  
Armstrong Kushan, multi-layered wood flooring imports from China, fourth administrative review                    
Loss Contingencies [Line Items]                    
Countervailing duties rate   0.85% 1.06%              
Antidumping duties rate 0.00%