Annual report pursuant to Section 13 and 15(d)

Summary of Significant Accounting Policies - Narrative (Details)

v3.20.4
Summary of Significant Accounting Policies - Narrative (Details)
 3 Months Ended 12 Months Ended
Dec. 31, 2020
USD ($)
subsidiary
Sep. 30, 2020
USD ($)
Jun. 30, 2020
USD ($)
Dec. 31, 2020
USD ($)
reporting_unit
subsidiary
segment
Dec. 31, 2019
USD ($)
Jan. 01, 2020
USD ($)
Accounting Policies [Line Items]            
Number of operating segments | segment       2    
Number of reportable segments | segment       2    
Inventory write-down       $ 3,800,000 $ 200,000  
Goodwill impairment       16,203,000 0  
Deferred charges and intangible assets $ 31,700,000     31,700,000 32,600,000  
Accumulated amortization on deferred charges 19,800,000     19,800,000 16,600,000  
Amortization expense       3,028,000 3,486,000  
Shipping costs       8,000,000.0 10,900,000  
Research and development expense       500,000 600,000  
Retained earnings 42,835,000     42,835,000 70,552,000  
Total lease liabilities 33,638,000     33,638,000    
Right-of-use assets, operating leases, net 31,769,000     31,769,000 35,772,000  
Deferred tax assets 1,957,000     $ 1,957,000 790,000  
Accounting Standards Update 2016-13 | Cumulative Effect, Period of Adoption, Adjustment            
Accounting Policies [Line Items]            
Retained earnings           $ 400,000
Software Licenses            
Accounting Policies [Line Items]            
Useful life of property, plant and equipment       5 years    
Customer List            
Accounting Policies [Line Items]            
Weighted average amortization period for intangible assets       11 years    
Estimated fair market value     $ 0      
Impairment charge     $ 1,300,000      
MUSA-Galvanized | Earn-Out Payment            
Accounting Policies [Line Items]            
Period for which earn out payments will be received       4 years    
MUSA-Stainless | Earn-Out Payment            
Accounting Policies [Line Items]            
Period for which earn out payments will be received       4 years    
Obsolescence Reserve            
Accounting Policies [Line Items]            
Inventory reserves 200,000     $ 200,000 300,000  
Physical Inventory Shrink Reserve            
Accounting Policies [Line Items]            
Inventory reserves $ 500,000     $ 500,000 $ 400,000  
Minimum            
Accounting Policies [Line Items]            
Accounts receivable, payment terms       30 days    
Amortization period for intangible assets       8 years    
Minimum | Land Improvement and Buildings            
Accounting Policies [Line Items]            
Useful life of property, plant and equipment       10 years    
Minimum | Machinery, Fixtures and Equipment            
Accounting Policies [Line Items]            
Useful life of property, plant and equipment       3 years    
Maximum            
Accounting Policies [Line Items]            
Accounts receivable, payment terms       60 days    
Amortization period for intangible assets       15 years    
Maximum | Land Improvement and Buildings            
Accounting Policies [Line Items]            
Useful life of property, plant and equipment       40 years    
Maximum | Machinery, Fixtures and Equipment            
Accounting Policies [Line Items]            
Useful life of property, plant and equipment       20 years    
American Stainless | American Stainless Tubing, Inc. | Earn-Out Payment            
Accounting Policies [Line Items]            
Period for which earn out payments will be received       3 years    
Earn out payments, target percentage 6.50%     6.50%    
Metals Segment            
Accounting Policies [Line Items]            
Number of reporting units | reporting_unit       3    
Number of subsidiaries | subsidiary 4     4    
Goodwill impairment $ 5,500,000 $ 10,700,000   $ 16,203,000    
Metals Segment | Synalloy Metals, Inc.            
Accounting Policies [Line Items]            
Ownership percentage of subsidiary       100.00%    
Specialty Chemicals Segment            
Accounting Policies [Line Items]            
Number of reporting units | reporting_unit       1    
Number of subsidiaries | subsidiary 2     2    
Goodwill impairment $ 0     $ 0    
Specialty Chemicals Segment | Manufacturers Soap and Chemical Company            
Accounting Policies [Line Items]            
Ownership percentage of subsidiary       100.00%