Noncontrolling Interest - Summary of Activity for Equity Attributable to Noncontrolling Interest (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
December 31, 2017	$ 446,558
Net income attributable to noncontrolling interest	6,870	$ 0
March 31, 2018	451,019
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	(2,409)
Net income attributable to noncontrolling interest	6,870
March 31, 2018	$ 451,019