NATURE OF OPERATIONS - Earnings per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Accounting Policies [Abstract]
Net income	$ 14,317	$ 12,736	$ 31,211	$ 36,404
Weighted average common shares outstanding - basic (in shares)	52,001,097	55,654,429	53,359,460	56,094,285
Add: Dilutive effects of assumed vesting of restricted stock (in shares)	156,106	273,104	118,309	219,587
Weighted average common shares outstanding - diluted (in shares)	52,157,203	55,927,533	53,477,769	56,313,872
Basic earnings per common share (in usd per share)	$ 0.28	$ 0.23	$ 0.58	$ 0.65
Diluted earnings per common share (in usd per share)	$ 0.27	$ 0.23	$ 0.58	$ 0.65
Anti-dilutive shares not included in calculation of diluted earnings per share (in shares)	26	4,398	17,623	4,381