STOCK BASED AND OTHER COMPENSATION PLANS - Stock Based Compensation Plans Summary (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized equity based compensation expense	$ 3,575	$ 2,162	$ 18,336	$ 6,667
Ladder Capital Corp Deferred Compensation Plan	0	601	0	1,519
Bonus Expense	6,533	9,210	21,035	26,772
Other Employee/Director Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized equity based compensation expense	6	13	23	45
Phantom Equity Investment Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized equity based compensation expense	343	0	1,047	0
Annual Incentive Awards Granted in 2015 with Respect to 2014 Performance | 2014 Omnibus Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized equity based compensation expense	0	0	0	172
Annual Incentive Awards Granted in 2016 with Respect to 2015 Performance | 2014 Omnibus Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized equity based compensation expense	0	323	131	971
Annual Incentive Awards Granted in 2017 With Respect to 2016 Performance | 2014 Omnibus Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized equity based compensation expense	280	524	955	1,655
Other 2017 Restricted Stock Awards | 2014 Omnibus Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized equity based compensation expense	25	76	102	257
Annual Incentive Awards Granted in 2017 With Respect to 2017 Performance | 2014 Omnibus Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized equity based compensation expense	596	1,122	1,961	3,325
2018 Restricted Stock Awards | 2014 Omnibus Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized equity based compensation expense	0	95	32	230
Other 2018 Restricted Stock Awards | 2014 Omnibus Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized equity based compensation expense	11	9	31	12
Annual Incentive Awards Granted in 2019 with Respect to 2018 Performance | 2014 Omnibus Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized equity based compensation expense	2,509	0	14,804	0
Other 2019 Restricted Stock Awards | 2014 Omnibus Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized equity based compensation expense	$ 148	$ 0	$ 297	$ 0