NATURE OF OPERATIONS - Earnings per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Accounting Policies [Abstract]
Net income	$ 9,318	$ 11,658	$ 16,894	$ 23,668
Weighted average common shares outstanding - basic (in shares)	52,465,458	56,108,618	54,038,642	56,314,213
Add: Dilutive effects of assumed vesting of restricted stock (in shares)	85,548	182,770	99,410	192,829
Weighted average common shares outstanding - diluted (in shares)	52,551,006	56,291,388	54,138,052	56,507,042
Basic earnings per common share (in usd per share)	$ 0.18	$ 0.21	$ 0.31	$ 0.42
Diluted earnings per common share (in usd per share)	$ 0.18	$ 0.21	$ 0.31	$ 0.42
Anti-dilutive shares not included in calculation of diluted earnings per share (in shares)	13,734	5,762	18,980	6,701