Revenue (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disaggregation of Revenue
Revenues from contracts with customers									$ 4,133,139	$ 3,018,685	$ 2,161,071
Income from derivatives and other sources									6,487	636,889	(416,546)
Total revenue and other	$ 1,045,649	$ 1,076,532	$ 989,344	$ 1,028,101	$ 1,021,726	$ 647,880	$ 790,389	$ 1,195,579	4,139,626	3,655,574	1,744,525
Natural gas sales
Disaggregation of Revenue
Revenues from contracts with customers									2,287,939	1,769,284	1,260,750
Oil sales
Disaggregation of Revenue
Revenues from contracts with customers									187,178	108,195	61,319
Marketing
Disaggregation of Revenue
Revenues from contracts with customers									458,901	258,045	393,049
Exploration and production
Disaggregation of Revenue
Total revenue and other									3,565,300	3,406,203	1,334,656
Exploration and production | Natural gas sales
Disaggregation of Revenue
Revenues from contracts with customers									2,287,939	1,769,284	1,260,750
Exploration and production | Natural gas liquids sales (ethane)
Disaggregation of Revenue
Revenues from contracts with customers									172,653	93,041	52,949
Exploration and production | Natural gas liquids sales (C3+ NGLs)
Disaggregation of Revenue
Revenues from contracts with customers									1,005,124	777,400	380,043
Exploration and production | Oil sales
Disaggregation of Revenue
Revenues from contracts with customers									187,178	108,195	61,319
Gathering and compression
Disaggregation of Revenue
Total revenue and other									17,817	11,386	16,028
Gathering and compression | Gathering and compression
Disaggregation of Revenue
Revenues from contracts with customers									17,817	11,386	12,169
Water handling and treatment
Disaggregation of Revenue
Total revenue and other									3,527	1,334	792
Water handling and treatment | Water handling and treatment
Disaggregation of Revenue
Revenues from contracts with customers									3,527	1,334	792
Marketing
Disaggregation of Revenue
Total revenue and other									552,982	236,651	393,049
Marketing | Marketing
Disaggregation of Revenue
Revenues from contracts with customers									$ 458,901	$ 258,045	$ 393,049