Annual report pursuant to Section 13 and 15(d)

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

v3.10.0.1
Fair Value Measurement - Fair Value and Carrying Value of Long-term Debt (Details) - USD ($)
$ in Thousands
Dec. 31, 2018
Dec. 31, 2017
Fair Value    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-term debt value (Level 2) $ 211,823 $ 160,108
Carrying Value    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-term debt value (Level 2) $ 212,687 $ 160,598