Fair Value Measurements (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Assets
Derivative assets		$ 4,344
Non-current liabilities
Derivative liability	$ (8,243)
Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets
Derivative assets		0
Non-current liabilities
Derivative liability	0
Significant Other Observable Inputs (Level 2)
Assets
Derivative assets		4,344
Non-current liabilities
Derivative liability	(8,243)
Significant Unobservable Inputs (Level 3)
Assets
Derivative assets		$ 0
Non-current liabilities
Derivative liability	$ 0