Annual report pursuant to Section 13 and 15(d)

Accounts Receivable and Major Customers - Additional Information (Detail)

v3.19.3.a.u2
Accounts Receivable and Major Customers - Additional Information (Detail)
$ in Thousands
 12 Months Ended
Dec. 31, 2019
USD ($)
Customer
Dec. 31, 2018
USD ($)
Customer
Accounts, Notes, Loans and Financing Receivable [Line Items]    
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification   $ 2,700
Customers $ 63,165 $ 59,030
Accounts Receivable | Customer Concentration Risk    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Number of major customers | Customer 4 3
Revenues, major customers $ 354,600 $ 304,300
Concentration risk, percentage 76.00% 69.00%
Accounts Receivable | Customer Concentration Risk | Major Customer 1    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Revenues, major customers $ 172,300 $ 173,000
Concentration risk, percentage 37.00% 39.00%
Accounts Receivable | Customer Concentration Risk | Major Customer 2    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Revenues, major customers $ 84,600 $ 71,500
Concentration risk, percentage 18.00% 16.00%
Accounts Receivable | Customer Concentration Risk | Major Customer 3    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Revenues, major customers $ 50,700 $ 59,800
Concentration risk, percentage 11.00% 14.00%
Accounts Receivable | Customer Concentration Risk | Major Customer Four [Domain]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Revenues, major customers $ 47,000  
Concentration risk, percentage 10.00%  
Accounts Receivable | Credit Concentration Risk    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Concentration risk, percentage 70.00% 48.00%
Accounts receivable, major customers $ 44,500 $ 28,600