Summary of Significant Accounting Policies (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017
Statement of Cash Flows [Abstract]
Non-cash loss on extinguishment of debt, net		$ 0	$ 22
Loss on extinguishment of debt		0	35
Net cash provided by operating activities		140,135	134,979
Net cash provided by investing activities		189,259	514,827
Cash paid for extinguishment of debt		0	(13)
Net cash used in financing activities		0	(2,517)
Net change in cash, cash equivalents, and restricted cash			647,289
Cash, cash equivalents, and restricted cash at beginning of period	[1]	313,943	12,372
Cash, cash equivalents, and restricted cash at end of period	[1]	643,337	659,661
Income Statement [Abstract]
Exploration		13,727	11,817
General and administrative		27,682	28,817
Total operating expenses		310,527	206,577
Income from operations		459,068	166,161
Other non-operating income (expense), net		$ 409	(233)
As Reported
Statement of Cash Flows [Abstract]
Non-cash loss on extinguishment of debt, net			22
Net cash provided by operating activities			134,966
Other, net			2,486
Net cash provided by investing activities			517,313
Net cash used in financing activities			(2,504)
Net change in cash and cash equivalents			649,775
Cash and cash equivalents at beginning of period			9,372
Cash and cash equivalents at end of period			659,147
Income Statement [Abstract]
Exploration			11,978
General and administrative			29,224
Total operating expenses			207,145
Income from operations			165,593
Other non-operating income (expense), net			$ 335

[1] Refer to Note 1 - Summary of Significant Accounting Policies for a reconciliation of cash, cash equivalents, and restricted cash reported to the amounts reported within the accompanying condensed consolidated balance sheets (“accompanying balance sheets”).