EARNINGS PER SHARE - Schedule of Calculation of Basic and Diluted EPS (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Denominator:
Weighted average number of shares of Class A common stock outstanding (in shares)	96,810,266	80,108,431	96,003,151	76,510,201
Basic net income (loss) per share of Class A common stock (in dollars per share)	$ 0.40	$ 0.28	$ 0.93	$ 0.47
Denominator:
Weighted average number of shares of Class A common stock outstanding (in shares)	96,810,266	80,108,431	96,003,151	76,510,201
Diluted weighted average number of shares of Class A common stock outstanding (in shares)	97,165,899	110,055,308	96,276,824	109,693,706
Diluted net income per share of Class A common stock (in dollars per share)	$ 0.40	$ 0.26	$ 0.93	$ 0.45
Class A Common Stock
Numerator:
Net income (loss) attributable to Class A common shareholders	$ 38,406	$ 22,113	$ 89,281	$ 35,584
Denominator:
Weighted average number of shares of Class A common stock outstanding (in shares)	96,810,266	80,108,431	96,003,151	76,510,201
Basic net income (loss) per share of Class A common stock (in dollars per share)	$ 0.40	$ 0.28	$ 0.93	$ 0.47
Numerator:
Net income (loss) attributable to Class A common shareholders	$ 38,406	$ 22,113	$ 89,281	$ 35,584
Amounts attributable to operating partnership’s share of Ladder Capital Corp net income (loss)	0	8,868	0	14,706
Additional corporate tax (expense) benefit	0	(2,014)	0	(1,286)
Diluted Net income (loss) available for Class A common shareholders	$ 38,406	$ 28,967	$ 89,281	$ 49,004
Denominator:
Weighted average number of shares of Class A common stock outstanding (in shares)	96,810,266	80,108,431	96,003,151	76,510,201
Shares issuable relating to converted Class B common shareholders (in shares)	0	29,723,350	0	33,013,753
Incremental shares of unvested Class A restricted stock (in shares)	355,633	223,527	273,673	169,752
Diluted weighted average number of shares of Class A common stock outstanding (in shares)	97,165,899	110,055,308	96,276,824	109,693,706
Diluted net income per share of Class A common stock (in dollars per share)	$ 0.40	$ 0.26	$ 0.93	$ 0.45