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