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Debt and Notes Payable - Related Party, Schedule of Debt (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Mar. 29, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Net unamortized discount and debt issuance costs	$ (10,620)		$ (4,717)
Debt	989,380		905,283
Line of Credit [Member] \| VLP Revolver [Member]
Debt Instrument [Line Items]
Debt, gross	0		410,000
Senior Notes [Member]
Debt Instrument [Line Items]
Debt	$ 989,380		495,283
Senior Notes [Member] \| Senior Notes Due December 2026 [Member]
Debt Instrument [Line Items]
Senior notes, stated rate (percent)	4.375%
Debt, gross	$ 500,000		500,000
Senior Notes [Member] \| Senior Notes Due March 2028 [Member]
Debt Instrument [Line Items]
Senior notes, stated rate (percent)	4.50%	4.50%
Debt, gross	$ 500,000		$ 0