Compensation Plans - Common Units Subject to Vesting (Details)
12 Months Ended
Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]  
Nonvested at beginning of period (in shares) 775,979
Granted (in shares) 288,444
Vested (in shares) (235,756)
Forfeited (in shares) (12,008)
Nonvested at end of period (in shares) 816,659