Annual report pursuant to Section 13 and 15(d)

Investments and Fair Value Measurements - Category of Financial Instruments Not Held at Fair Value (Detail)

v3.20.4
Investments and Fair Value Measurements - Category of Financial Instruments Not Held at Fair Value (Detail) - USD ($)
$ in Thousands
Dec. 31, 2020
Dec. 31, 2019
Carrying Amount    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Financial Assets, Investments $ 914 $ 1,781
Carrying Amount | Level I    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Financial Assets, Cash and cash equivalents 62,498 52,832
Carrying Amount | Level II    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Financial Liabilities, Borrowings under credit facility 12,600 16,200
Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Financial Assets, Investments 914 1,781
Fair Value | Level I    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Financial Assets, Cash and cash equivalents 62,498 52,832
Fair Value | Level II    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Financial Liabilities, Borrowings under credit facility $ 12,600 $ 16,200