Equity Based Compensation and Cash Awards - Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Equity based compensation
Equity based compensation expense	$ 13,529	$ 12,778	$ 73,517
Series B Units and Exchanged B Units
Equity based compensation
Equity based compensation expense			65,639
Stock options
Equity based compensation
Equity based compensation expense			98
AM LTIP RSUs
Equity based compensation
Equity based compensation expense	11,461	9,964	5,440
ROIC PSUs
Equity based compensation
Equity based compensation expense	1,158	1,912	1,261
Equity awards issued to directors
Equity based compensation
Equity based compensation expense	$ 910	$ 902	$ 1,079