Fair Value Measurement - Fair Value of Financial Instruments (Details) - Senior Notes - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
2024 Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Amount	$ 325,000	$ 325,000
Estimated Fair Value	323,375	337,188
2027 Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Amount	300,000	300,000
Estimated Fair Value	$ 289,500	$ 301,500