Financial Instruments - Fair Value of the Interest Rate Derivative (Details) - Fair Value, Recurring - Interest Rate Swap - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Derivative Assets
Other current assets	$ 0	$ 216
Other non-current assets	0	0
Total assets at fair value	0	216
Derivative Liabilities
Other current liabilities	(4,925)	(61)
Other non-current liabilities	(4,769)	(398)
Total liabilities at fair value	(9,694)	(459)
Level 1
Derivative Assets
Other current assets	0	0
Other non-current assets	0	0
Total assets at fair value	0	0
Derivative Liabilities
Other current liabilities	0	0
Other non-current liabilities	0	0
Total liabilities at fair value	0	0
Level 2
Derivative Assets
Other current assets	0	216
Other non-current assets	0	0
Total assets at fair value	0	216
Derivative Liabilities
Other current liabilities	(4,925)	(61)
Other non-current liabilities	(4,769)	(398)
Total liabilities at fair value	(9,694)	(459)
Level 3
Derivative Assets
Other current assets	0	0
Other non-current assets	0	0
Total assets at fair value	0	0
Derivative Liabilities
Other current liabilities	0	0
Other non-current liabilities	0	0
Total liabilities at fair value	$ 0	$ 0