Annual report pursuant to Section 13 and 15(d)

Fair Value Measurement - Fair Value and Carrying Value of Long-term Debt (Details)

v3.20.4
Fair Value Measurement - Fair Value and Carrying Value of Long-term Debt (Details) - USD ($)
$ in Thousands
Dec. 31, 2020
Dec. 31, 2019
Fair Value    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-term debt value (level 2) $ 363,460 $ 309,377
Carrying Value    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-term debt value (level 2) $ 357,536 $ 307,508