Incentive Plans (Changes in Time-Lapse Restricted Stock and Restricted Stock Units Outstanding) (Details) - Restricted Stock and Restricted Stock Units [Member] - shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Schedule of Share based Compensation Arrangements by Share based Payment Award, Equity Instruments, Other Than Options, Restricted Stock Units [Line Items]
Balance at beginning of year	321,789	112,881	98,477
Granted	282,065	278,892	38,184
Vested and issued	(69,610)	(54,884)	(34,696)
Forfeited	(57,000)	(15,100)
Murphy USA Inc. spin-off adjustment			10,916
Balance at end of year	477,244	321,789	112,881