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Summary of Significant Accounting Policies - Narrative (Details)
12 Months Ended
Dec. 31, 2019
USD ($)
Institution
Segment
Dec. 31, 2018
USD ($)
Dec. 31, 2017
USD ($)
Nov. 30, 2019
USD ($)
Jan. 01, 2019
USD ($)
Properties and Equipment          
Number of operating segments | Segment 1        
Operating lease liability $ 35,801,000        
Operating lease right-of-use asset $ 35,916,000        
Number of financial institutions | Institution 4        
Amortization of unproved properties included in depreciation, depletion and amortization $ 32,600,000 $ 82,300,000 $ 52,800,000    
Assets legally restricted for purposes of settling asset retirement obligations $ 0        
ASU 2016-02          
Properties and Equipment          
Operating lease liability         $ 44,600,000
Operating lease right-of-use asset         $ 44,600,000
Buildings | Minimum          
Properties and Equipment          
Estimated useful life 25 years        
Buildings | Maximum          
Properties and Equipment          
Estimated useful life 40 years        
Other Assets | Minimum          
Properties and Equipment          
Estimated useful life 3 years        
Other Assets | Maximum          
Properties and Equipment          
Estimated useful life 25 years        
Meade          
Properties and Equipment          
Escrow related to certain contingencies       $ 13,600,000  
Customer One | Sales Revenue, Net | Customer          
Concentration Risk [Line Items]          
Percentage of Total Sales 17.00% 20.00% 18.00%    
Customer Two | Sales Revenue, Net | Customer          
Concentration Risk [Line Items]          
Percentage of Total Sales 16.00% 11.00% 11.00%    
Customer Three | Sales Revenue, Net | Customer          
Concentration Risk [Line Items]          
Percentage of Total Sales 16.00%