Common Stock (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Member Units | Bold Contribution Agreement
Capital Unit [Line Items]
Stock conversion (in shares)			1
Class A Common Stock
Capital Unit [Line Items]
Common stock, shares issued (in shares)	29,150,220		29,150,220		28,696,321
Common stock, shares outstanding (in shares)	29,150,220		29,150,220		28,696,321
Class A Common Stock | Bold Contribution Agreement
Capital Unit [Line Items]
Stock conversion (in shares)			1
Class A Common Stock | 2014 Plan
Capital Unit [Line Items]
Common shares issued during period under stock plan (in shares)	167,827	115,574	569,883	569,585
Common stock repurchased (in shares)	49,111	30,511	151,716	142,937
Class B Common Stock
Capital Unit [Line Items]
Common stock, shares issued (in shares)	35,416,446		35,416,446		35,452,178
Common stock, shares outstanding (in shares)	35,416,446		35,416,446		35,452,178
EEH Units and Class B Common Stock converted to Class A Common Stock (in shares)	35,732	183,894	35,732	389,135