Long-Term Debt - Debt Modification and Extinguishments (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended	12 Months Ended
	Jun. 30, 2019	Jun. 30, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Previously deferred financing costs extinguished		$ 1,395	$ 4,207
May 2019 issuance | Senior Notes
Debt Instrument [Line Items]
Original premium extinguished	$ (588)	(588)
Previously deferred financing costs extinguished	1,395	1,395
Total other expense and loss on extinguishment	807	807
New deferred financing costs	$ 4,956	$ 4,956