Fair Value Measurements - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Assets:
Noncurrent derivative instruments	$ 9,293	$ 0
Net Amounts Presented in the Balance Sheets	16,887
Liabilities:
Total liabilities	(8,324)
Recurring
Assets:
Derivative instruments	7,594	50
Noncurrent derivative instruments	9,293
Net Amounts Presented in the Balance Sheets	16,887
Liabilities:
Derivative instruments	(8,324)	(65,467)
Noncurrent derivative instruments		(3,006)
Total liabilities		(68,473)
Net derivative liability	8,563	(68,423)
Recurring | Level 2
Assets:
Derivative instruments	3,879	50
Noncurrent derivative instruments	7,434
Net Amounts Presented in the Balance Sheets	11,313
Liabilities:
Derivative instruments	(8,324)	(57,927)
Noncurrent derivative instruments		(1,694)
Total liabilities		(59,621)
Net derivative liability	2,989	(59,571)
Recurring | Level 3
Assets:
Derivative instruments	3,715	0
Noncurrent derivative instruments	1,859
Net Amounts Presented in the Balance Sheets	5,574
Liabilities:
Derivative instruments	0	(7,540)
Noncurrent derivative instruments		(1,312)
Total liabilities		(8,852)
Net derivative liability	$ 5,574	$ (8,852)