Revolving Credit Facility (Details) - USD ($) $ in Thousands		Jul. 23, 2019	Jun. 30, 2019	Apr. 18, 2019	Mar. 31, 2019	Dec. 31, 2018
Line of Credit Facility [Line Items]
Credit facility balance			$ 118,000			$ 0
Line of Credit | Revolving Credit Facility
Line of Credit Facility [Line Items]
Line of credit agreement, maximum loan amount			2,500,000
Line of credit facility, current borrowing base				$ 1,600,000	$ 1,500,000
Line of credit agreement, aggregate lender commitments			1,200,000	$ 1,200,000	$ 1,000,000	1,000,000
Credit facility balance	[1]		118,000			0
Letters of credit	[2]		0			200
Available borrowing capacity			1,082,000			999,800
Unamortized deferred financing costs			$ 6,700			$ 6,400
Line of Credit | Revolving Credit Facility | Subsequent Event [Member]
Line of Credit Facility [Line Items]
Line of credit agreement, aggregate lender commitments		$ 1,200,000
Credit facility balance	[1]	126,000
Letters of credit	[2]	0
Available borrowing capacity		$ 1,074,000

[1] ⁽¹⁾  Unamortized deferred financing costs attributable to the credit facility are presented as a component of other noncurrent assets on the accompanying balance sheets and totaled $6.7 million and $6.4 million as of June 30, 2019, and December 31, 2018, respectively. These costs are being amortized over the term of the credit facility on a straight-line basis.

[2] ⁽²⁾  Letters of credit outstanding reduce the amount available under the credit facility on a dollar-for-dollar basis. The letter of credit outstanding as of December 31, 2018, was released during the three months ended March 31, 2019.