EQUITY (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended		3 Months Ended		6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Class A common stock
EQUITY
Issuance of common stock (in shares)	282,347	383,001
Class B common stock
EQUITY
Common stock retired (in shares)		316,370
Inventive units retired (in shares)	263,276
Incentive Units
EQUITY
Inventive units retired (in shares)	35,000	162,871
Common units acquired (in shares)	282,347	383,001
Fair value of the stock option grants determined with assumptions
Compensation expense recognized			$ 3,905	$ 4,020	$ 7,752	$ 7,039
Stock options | Class A common stock
Fair value of the stock option grants determined with assumptions
Compensation expense recognized			$ 1,343	$ 1,158	$ 2,530	$ 2,060
Restricted Stock Units (RSUs)
Changes in unvested common stock
Outstanding at the beginning of the period					98,061
Forfeited					(7,707)
Outstanding at the end of the period	90,354		90,354		90,354
Changes in unvested common stock, Grant Date Fair Value
Outstanding at the beginning of the period					$ 27.90
Forfeited					27.90
Outstanding at the end of the period	$ 27.90		$ 27.90		$ 27.90
Common Stock | Class A common stock
Changes in unvested common stock
Outstanding at the beginning of the period					53,293
Forfeited					(834)
Outstanding at the end of the period	52,459		52,459		52,459
Changes in unvested common stock, Grant Date Fair Value
Outstanding at the beginning of the period					$ 33.00
Forfeited					33.00
Outstanding at the end of the period	$ 33.00		$ 33.00		$ 33.00
Common Stock | Stock options
Changes in stock options
Outstanding at the beginning of the period					1,832,966
Exercised					(5,878)
Forfeited					(21,817)
Outstanding at the end of the period	1,805,271		1,805,271		1,805,271
Vested					709,498
Changes in stock option, Weighted Average Exercise Price
Outstanding at the beginning of the period					$ 30.42
Exercised					28.50
Forfeited					29.27
Outstanding at the end of the period	$ 30.44		$ 30.44		30.44
Vested					$ 32.06
Changes in unvested common stock
Vested					(709,498)
Changes in unvested common stock, Grant Date Fair Value
Vested					$ 32.06