XML 51 R39.htm IDEA: XBRL DOCUMENT v3.10.0.1
Fair Value Measurements - Estimated Fair Value and Carrying Value of Long-Term Debt (Details) - Secured Notes - New Building Note - USD ($)
$ in Thousands
Jun. 30, 2018
Dec. 31, 2017
Oct. 04, 2016
Fair Value Assets And Liabilities Measured On Recurring Basis      
Fair Value     $ 36,600
Fair Value Measurements Level 2      
Fair Value Assets And Liabilities Measured On Recurring Basis      
Fair Value $ 0 $ 42,526  
Carrying value $ 0 $ 37,502