SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Numerator for basic earnings per share:
Net income from continuing operations									$ 37,411	$ 26,564	$ 12,003
Less: Dividends on preferred stock									461	479	489
Net income from continuing operations available to common shareholders - basic									36,950	26,085	11,514
Net income from discontinued operations available to common shareholders - basic and diluted									0	427	0
Net income available to common shareholders									36,950	26,512	11,514
Numerator for diluted earnings per share:
Net income from continuing operations available to common shareholders - basic									36,950	26,085	11,514
Add: Dividends on preferred stock									0	0	489
Add: Interest on subordinated debt (tax effected)									0	0	753
Net income available to common shareholders from continuing operations - diluted									$ 36,950	$ 26,085	$ 12,756
Denominator:
Total average shares outstanding (in shares)									11,821,574	11,713,885	11,030,984
Effect of dilutive convertible preferred stock (in shares)									0	0	489,625
Effect of dilutive convertible subordinated debt (in shares)									0	0	837,500
Effect of dilutive stock options and restricted stock units (in shares)									266,532	330,782	363,894
Total diluted average shares outstanding (in shares)									12,088,106	12,044,667	12,722,003
Earnings per share from continuing operations - basic (in dollars per share)									$ 3.13	$ 2.22	$ 1.04
Earnings per share from discontinued operations - basic (in dollars per share)									0	0.04	0
Earnings per common share - basic (in dollars per share)	$ 1.00	$ 0.53	$ 1.50	$ 0.08	$ 0.34	$ 0.36	$ 1.31	$ 0.26	3.13	2.26	1.04
Earnings per share from continuing operations - diluted (in dollars per share)									3.06	2.16	1.00
Earnings per share from discontinued operations - diluted (in dollars per share)									0	0.04	0
Earnings per common share - diluted (in dollars per share)	$ 0.97	$ 0.53	$ 1.49	$ 0.08	$ 0.32	$ 0.35	$ 1.18	$ 0.26	$ 3.06	$ 2.20	$ 1.00