EARNINGS PER SHARE - Schedule of Calculation of Basic and Diluted EPS (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Denominator:
Weighted average number of shares of Class A common stock outstanding (in shares)	106,004,152	96,935,986	105,264,752	96,317,513
Basic net income (loss) per share of Class A common stock (in dollars per share)	$ 0.26	$ 0.69	$ 0.78	$ 1.62
Denominator:
Weighted average number of shares of Class A common stock outstanding (in shares)	106,004,152	96,935,986	105,264,752	96,317,513
Diluted weighted average number of shares of Class A common stock outstanding (in shares)	106,603,713	110,650,253	106,232,581	110,482,991
Diluted net income (loss) per share of Class A common stock (in dollars per share)	$ 0.26	$ 0.67	$ 0.77	$ 1.61
Class A Common Stock
Numerator:
Net income (loss) attributable to Class A common shareholders	$ 27,576	$ 66,630	$ 81,996	$ 155,911
Denominator:
Weighted average number of shares of Class A common stock outstanding (in shares)	106,004,152	96,935,986	105,264,752	96,317,513
Basic net income (loss) per share of Class A common stock (in dollars per share)	$ 0.26	$ 0.69	$ 0.78	$ 1.62
Numerator:
Net income (loss) attributable to Class A common shareholders	$ 27,576	$ 66,630	$ 81,996	$ 155,911
Amounts attributable to operating partnership’s share of Ladder Capital Corp net income (loss)	0	8,991	0	22,786
Additional corporate tax (expense) benefit	0	(1,583)	0	(822)
Diluted net income (loss) attributable to Class A common shareholders	$ 27,576	$ 74,038	$ 81,996	$ 177,875
Denominator:
Weighted average number of shares of Class A common stock outstanding (in shares)	106,004,152	96,935,986	105,264,752	96,317,513
Shares issuable relating to converted Class B common shareholders (in shares)	0	13,202,202	0	13,800,597
Incremental shares of unvested Class A restricted stock (in shares)	599,561	512,065	967,829	364,881
Diluted weighted average number of shares of Class A common stock outstanding (in shares)	106,603,713	110,650,253	106,232,581	110,482,991
Diluted net income (loss) per share of Class A common stock (in dollars per share)	$ 0.26	$ 0.67	$ 0.77	$ 1.61