CAPITAL STOCK AND SHARE-BASED COMPENSATION - Non-Vested Stock Option Activity (Details)	12 Months Ended
	Dec. 31, 2020 $ / shares shares
Number of Shares
Non-vested stock options beginning balance (shares) | shares	305,750
Granted (shares) | shares	43,249
Vested (shares) | shares	(142,233)
Forfeited (shares) | shares	(18,154)
Non-vested stock options ending balance (shares) | shares	188,612
Weighted Average Grant Date Fair Value
Non-vested stock options beginning balance (usd per share) | $ / shares	$ 41.66
Granted (usd per share) | $ / shares	86.72
Vested (usd per share) | $ / shares	34.84
Forfeited (usd per share) | $ / shares	47.66
Non-vested stock options ending balance (usd per share) | $ / shares	$ 56.55