CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME
Net income		$ 110,141	$ 75,789	$ 28,707
Other comprehensive income:
Unrealized (loss) gain on available-for-sale securities	[1]	(205)	87	(119)
Comprehensive income		109,936	75,876	28,588
Less: comprehensive loss attributable to non-controlling interest		(66)	(2,090)	(2,706)
Comprehensive income attributable to Magellan		$ 110,002	$ 77,966	$ 31,294

[1] Net of income tax (benefit) expense of $(68), $51 and $(8) for the years ended December 31, 2015, 2016 and 2017, respectively.