Earnings Per Share (Schedule Of Earnings Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Earnings Per Share [Abstract]
Net income attributable to HollyFrontier stockholders	$ 345,507	$ 57,767	$ 613,598	$ 12,299
Participating securities’ (restricted stock) share in earnings	1,196	373	2,147	752
Net income (loss) attributable to common shares	$ 344,311	$ 57,394	$ 611,451	$ 11,547
Average number of shares of common stock outstanding	175,899	176,147	176,256	176,141
Effect of dilutive variable restricted shares and performance share units	1,687	155	1,564	349
Average number of shares of common stock outstanding assuming dilution	177,586	176,302	177,820	176,490
Basic earnings (loss) per share	$ 1.96	$ 0.33	$ 3.47	$ 0.07
Diluted earnings (loss) per share	$ 1.94	$ 0.33	$ 3.44	$ 0.07
Excludes anti-dilutive restricted and performance share units of:	648	140	753	133