STOCK BASED AND OTHER COMPENSATION PLANS - Stock Based Compensation Plans Summary (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized equity based compensation expense	$ 2,105	$ 1,512
Ladder Capital Corp Deferred Compensation Plan	236	(431)	$ 919	$ 187
Bonus Expense	7,782	9,425	17,562	12,528
Omnibus Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized equity based compensation expense	2,105	1,512	4,505	8,766
Omnibus Incentive Plan | Annual Incentive Awards Granted in 2015 With Respect to 2014 Performance
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized equity based compensation expense	0	415	172	1,037
Omnibus Incentive Plan | Annual Incentive Awards Granted in 2016 With Respect to 2015 Performance
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized equity based compensation expense	325	430	647	1,215
Omnibus Incentive Plan | Annual Incentive Awards Granted in 2017 With Respect to 2016 Performance
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized equity based compensation expense	509	590	1,131	5,786
Omnibus Incentive Plan | Other 2017 Restricted Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized equity based compensation expense	76	56	181	147
Omnibus Incentive Plan | Annual Incentive Awards Granted in 2017 With Respect to 2017 Performance
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized equity based compensation expense	1,087	0	2,202	0
Omnibus Incentive Plan | 2018 Restricted Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized equity based compensation expense	93	0	136	0
Omnibus Incentive Plan | Other 2018 Restricted Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized equity based compensation expense	3	0	3	0
Other Employee/Director Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized equity based compensation expense	12	21	33	581
Phantom Equity Investment Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized equity based compensation expense	$ 0	$ 65	$ 0	$ 342