Fair Value Measurements (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Assets (Liabilities)
Total	$ (3,394)	$ (15,239)
Fair value on a recurring basis
Assets (Liabilities)
Derivative Asset	79	1,190
Derivative Liability	(3,473)	(16,429)
Total	(3,394)	(15,239)
Fair value on a recurring basis | Level 1
Assets (Liabilities)
Derivative Asset	0	0
Derivative Liability	0	0
Fair value on a recurring basis | Level 2
Assets (Liabilities)
Derivative Asset	79	1,190
Derivative Liability	(3,473)	(16,429)
Total	(3,394)	(15,239)
Fair value on a recurring basis | Level 3
Assets (Liabilities)
Derivative Asset	0	0
Derivative Liability	$ 0	$ 0