EQUITY BASED COMPENSATION (Details 3)	Mar. 31, 2013	Dec. 31, 2012
Equity Incentive Plan
Remaining vesting tranches for principals
Principal Units (in units)	27,821,333	17,920,926
Principals' equity based awards
Remaining vesting tranches for principals
Principal Units (in units)	65,508,898
Restricted Equity Units
Remaining vesting tranches for principals
Principal Units (in units)	1,047,639
April 1, 2013 | Equity Incentive Plan
Remaining vesting tranches for principals
Principal Units (in units)	2,995,026
April 1, 2013 | Principals' equity based awards
Remaining vesting tranches for principals
Principal Units (in units)	1,302,727
April 1, 2013 | Restricted Equity Units
Remaining vesting tranches for principals
Principal Units (in units)	199,177
October 1, 2013 | Equity Incentive Plan
Remaining vesting tranches for principals
Principal Units (in units)	3,595,220
October 1, 2013 | Principals' equity based awards
Remaining vesting tranches for principals
Principal Units (in units)	28,874,554
October 1, 2013 | Restricted Equity Units
Remaining vesting tranches for principals
Principal Units (in units)	259,411
April 1, 2014 | Equity Incentive Plan
Remaining vesting tranches for principals
Principal Units (in units)	4,623,595
April 1, 2014 | Principals' equity based awards
Remaining vesting tranches for principals
Principal Units (in units)	1,305,406
April 1, 2014 | Restricted Equity Units
Remaining vesting tranches for principals
Principal Units (in units)	168,409
October 1, 2014 | Equity Incentive Plan
Remaining vesting tranches for principals
Principal Units (in units)	3,900,038
October 1, 2014 | Principals' equity based awards
Remaining vesting tranches for principals
Principal Units (in units)	28,874,613
October 1, 2014 | Restricted Equity Units
Remaining vesting tranches for principals
Principal Units (in units)	252,751
April 1, 2015 | Equity Incentive Plan
Remaining vesting tranches for principals
Principal Units (in units)	4,521,424
April 1, 2015 | Principals' equity based awards
Remaining vesting tranches for principals
Principal Units (in units)	1,305,462
April 1, 2015 | Restricted Equity Units
Remaining vesting tranches for principals
Principal Units (in units)	142,360
October 1, 2015 | Equity Incentive Plan
Remaining vesting tranches for principals
Principal Units (in units)	2,991,037
October 1, 2015 | Principals' equity based awards
Remaining vesting tranches for principals
Principal Units (in units)	2,306,581
October 1, 2015 | Restricted Equity Units
Remaining vesting tranches for principals
Principal Units (in units)	25,531
April 1, 2016 | Equity Incentive Plan
Remaining vesting tranches for principals
Principal Units (in units)	2,195,642
April 1, 2016 | Principals' equity based awards
Remaining vesting tranches for principals
Principal Units (in units)	67,429
October 1, 2016 | Equity Incentive Plan
Remaining vesting tranches for principals
Principal Units (in units)	1,897,555
October 1, 2016 | Principals' equity based awards
Remaining vesting tranches for principals
Principal Units (in units)	1,345,833
April 1, 2017 | Equity Incentive Plan
Remaining vesting tranches for principals
Principal Units (in units)	42,434
April 1, 2017 | Principals' equity based awards
Remaining vesting tranches for principals
Principal Units (in units)	15,000
October 1, 2017 | Equity Incentive Plan
Remaining vesting tranches for principals
Principal Units (in units)	318,979
October 1, 2018 | Equity Incentive Plan
Remaining vesting tranches for principals
Principal Units (in units)	740,383
October 1, 2018 | Principals' equity based awards
Remaining vesting tranches for principals
Principal Units (in units)	111,293