EARNINGS PER SHARE (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Numerator:
Net income	$ 15,861	$ 15,117	$ 31,955	$ 28,189
Denominators:
Unvested restricted stock (in shares)	(2,000)	(2,000)	(2,000)	(2,000)
Effect of weighted average shares outstanding (in shares)	(7,000)	0	(84,000)	(129,000)
Weighted average common shares outstanding, basic (in shares)	51,389,000	48,370,000	51,312,000	48,241,000
Impact of potentially dilutive securities:
Dilutive effect of stock options and other stock awards (in shares)	197,000	249,000	194,000	240,000
Weighted average common shares outstanding, diluted	51,586,000	48,619,000	51,506,000	48,481,000
Anti-dilutive potentially issuable shares (in shares)	12,000	0	12,000	1,000
Class A Common Stock
Denominators:
Common stock, shares outstanding (in shares)	50,410,000	47,384,000	50,410,000	47,384,000	50,101,000
Class B Common Stock
Denominators:
Common stock, shares outstanding (in shares)	988,000	988,000	988,000	988,000	988,000