SHARE-BASED PAYMENT - Plan Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Restricted Shares
Restricted Shares - Shares
Nonvested at beginning of period (in shares)	1,122,614
Granted (in shares)	447,619
Vested (in shares)	(403,473)
Forfeited (in shares)	(44,067)
Nonvested at end of period (in shares)	1,122,693	1,122,614
Restricted Shares - Weighted Average Grant-date Fair Value
Nonvested at beginning of period (in dollars per share)	$ 62.41
Granted (in dollars per share)	101.48	$ 74.75	$ 48.39
Vested (in dollars per share)	61.16
Forfeited (in dollars per share)	79.65
Nonvested at end of period (in dollars per share)	$ 77.70	$ 62.41
Additional disclosures
Fair value, vested shares (in dollars)	$ 44,600	$ 30,400	$ 30,500
Unrecognized compensation
Unrecognized compensation for outstanding restricted shares/units	$ 51,100
Unrecognized compensation cost, period for recognition	3 years 8 months 12 days
Stock Option
Options
Outstanding at beginning of period (in shares)	461,340
Exercised (in shares)	(227,334)
Outstanding at end of period (in shares)	234,006	461,340
Exercisable at end of period (in shares)	234,006
Weighted Average Exercise Price
Outstanding at beginning of period (in dollars per share)	$ 22.51
Exercised (in dollars per share)	22.78
Outstanding at end of period (in dollars per share)	22.25	$ 22.51
Exercisable at end of period (in dollars per share)	$ 22.25
Weighted-Average Remaining Contract Life (Years)
Exercisable at end of period (in years)	3 years 8 months 12 days
Aggregate Intrinsic Value
Exercisable at end of period (in dollars)	$ 30,101
Intrinsic value of options exercised, (in dollars)	17,500	$ 21,600	2,700
Cash received from the exercise of options	$ 0	$ 0	$ 0
Restricted Stock Units (RSUs)
Restricted Shares - Shares
Nonvested at beginning of period (in shares)	770,493
Granted (in shares)	263,845
Vested (in shares)	(55,483)
Forfeited (in shares)	(196,709)
Cancelled (in shares)	(3,600)
Nonvested at end of period (in shares)	778,546	770,493
Restricted Shares - Weighted Average Grant-date Fair Value
Nonvested at beginning of period (in dollars per share)	$ 50.37
Granted (in dollars per share)	101.04	$ 50.26	$ 52.84
Vested (in dollars per share)	100.36
Forfeited (in dollars per share)	49.80
Cancelled (in dollars per share)	67.13
Nonvested at end of period (in dollars per share)	$ 67.66	$ 50.37
Additional disclosures
Fair value, vested shares (in dollars)	$ 5,600	$ 17,500	$ 26,600
Unrecognized compensation
Unrecognized compensation for outstanding restricted shares/units	$ 10,500
Unrecognized compensation cost, period for recognition	1 year 6 months