STOCK BASED COMPENSATION PLANS - Stock Based Compensation Plans Summary (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized equity based compensation expense	$ 18,965	$ 17,640	$ 13,788
Ladder Capital Corp Deferred Compensation Plan	568	710	(553)
Bonus Expense	33,747	29,224	34,359
2014 Omnibus Incentive Plan | 2015 Annual Restricted Stock/Option Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized equity based compensation expense	1,876	4,838	6,197
2014 Omnibus Incentive Plan | 2016 Annual Restricted Stock/Option Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized equity based compensation expense	2,094	6,690	0
2014 Omnibus Incentive Plan | 2017 Annual Restricted Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized equity based compensation expense	7,289	0	0
2014 Omnibus Incentive Plan | 2017 Other Restricted Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized equity based compensation expense	302	0	0
2014 Omnibus Incentive Plan | 2018 Annual Restricted Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized equity based compensation expense	6,768	0	0
Other Employee/Director Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized equity based compensation expense	636	6,112	7,591
Phantom Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized equity based compensation expense	$ 510	$ 689	$ (2,958)