Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements (Details)

v3.19.2
Fair Value Measurements (Details) - USD ($)
$ in Thousands
3 Months Ended 6 Months Ended
Jun. 30, 2019
Jun. 30, 2018
Jun. 30, 2019
Jun. 30, 2018
Dec. 31, 2018
Fair Value on Non-Recurring Basis          
Amount outstanding $ 745,589   $ 745,589    
Amount of transfers of assets and liabilities measured on a recurring and non-recurring basis between Levels 1, 2 and 3 of the fair value hierarchy 0 $ 0 0 $ 0  
Senior Notes          
Fair Value on Non-Recurring Basis          
Amount outstanding 400,000   400,000   $ 400,000
Fair Value on Non-Recurring Basis | Level 1 fair value measurement | Senior Notes          
Fair Value on Non-Recurring Basis          
Fair value $ 412,000   $ 412,000