Fair Value Measurements - Summary of Fair Value of Financial Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Financial assets
Derivative asset- current	$ 43,888	$ 184
Derivative asset	21,121	0
Financial liabilities
Derivative liability - current	528	11,805
Derivative liability - noncurrent	1,891	1,826
Fair Value on a Recurring Basis
Financial assets
Derivative asset- current	43,888	184
Derivative asset	21,121
Total financial assets	65,009	184
Financial liabilities
Derivative liability - current	528	11,805
Derivative liability - noncurrent	1,891	1,826
Total financial liabilities	2,419	13,631
Level 1 \| Fair Value on a Recurring Basis
Financial assets
Derivative asset- current	0	0
Derivative asset	0
Total financial assets	0	0
Financial liabilities
Derivative liability - current	0	0
Derivative liability - noncurrent	0	0
Total financial liabilities	0	0
Level 2 \| Fair Value on a Recurring Basis
Financial assets
Derivative asset- current	43,888	184
Derivative asset	21,121
Total financial assets	65,009	184
Financial liabilities
Derivative liability - current	528	11,805
Derivative liability - noncurrent	1,891	1,826
Total financial liabilities	2,419	13,631
Level 3 \| Fair Value on a Recurring Basis
Financial assets
Derivative asset- current	0	0
Derivative asset	0
Total financial assets	0	0
Financial liabilities
Derivative liability - current	0	0
Derivative liability - noncurrent	0	0
Total financial liabilities	$ 0	$ 0

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