NET INCOME (LOSS) PER SHARE ATTRIBUTABLE TO CLASS A COMMON SHAREHOLDERS (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Apr. 30, 2014
Numerator:
Net income (loss) attributable to holders of shares of Class A common stock - basic	$ 38,387	$ 33,104	$ (3,012)
Denominator:
Weighted average number of incremental shares issuable from unvested restricted stock, RSUs and stock options, as calculated using the treasury stock method	3,308,545	1,340,919
Class A common stock
Numerator:
Net income (loss) attributable to holders of shares of Class A common stock - basic	$ 38,387	$ 33,104	(3,012)
Net income (loss) attributable to holders of shares of Class A common stock - diluted	$ 38,387	$ 33,104	$ (3,012)
Denominator:
Weighted average shares of Class A common stock outstanding - basic	20,933,757	20,021,652	15,911,819
Weighted average shares of Class A common stock outstanding—diluted	24,242,302	21,362,571	15,911,819
Net income (loss) per share attributable to holders of shares of Class A common stock
Basic (in dollars per share)	$ 1.83	$ 1.65	$ (0.19)
Diluted (in dollars per share)	$ 1.58	$ 1.55	$ (0.19)
Number of Shares Issuable upon Exchange of Each Unit	1			1
Fully diluted shares of common stock outstanding if all Class A partnership units were to be exchanged for common stock immediately following the reorganization	58,061,255	55,481,167	54,250,854
Class A common stock | Restricted stock and RSUs
Net income (loss) per share attributable to holders of shares of Class A common stock
Number of antidilutive securities excluded from calculation of diluted income (loss) per share	16	1,380	2,315,512
Class A common stock | Stock options
Net income (loss) per share attributable to holders of shares of Class A common stock
Number of antidilutive securities excluded from calculation of diluted income (loss) per share	0	0	3,296,906