Non-controlling Interest - Ownership of common units in RMCO (Details) - shares	Dec. 31, 2020	Dec. 31, 2019
Shares
Total number of common stock units in RMCO	30,950,291	30,397,833
Ownership Percentage
Total percentage of common stock units	100.00%	100.00%
RMCO, LLC
Shares
Total number of common stock units in RMCO	18,390,691	17,838,233
Ownership Percentage
Holdings outstanding Class A common stock (equal to Holdings common units in RMCO)	59.40%	58.70%
RIHI | RMCO, LLC
Shares
Total number of common stock units in RMCO	12,559,600	12,559,600
Ownership Percentage
Non-controlling interest ownership of common units in RMCO as a percentage	40.60%	41.30%