Noncontrolling Interest - Summary of Activity for Equity Attributable to Noncontrolling Interest (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
December 31, 2017			$ 446,558
Net income attributable to noncontrolling interest	$ 822	$ (37,844)	7,692	$ (37,844)
June 30, 2018	451,700		451,700
Bold Transaction
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
December 31, 2017			446,558
EEH Units and Class B Common Stock converted to Class A Common Stock			(2,550)
Net income attributable to noncontrolling interest			7,692
June 30, 2018	$ 451,700		$ 451,700