EARNINGS PER SHARE (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
EARNINGS PER SHARE [Abstract]
Net income	$ 6,183,684	$ 5,043,050	$ 4,847,931	$ 3,978,604	$ 2,644,590	$ 2,714,832	$ 2,624,091	$ 3,344,753	$ 20,053,269	$ 11,328,266	$ 11,372,239
Weighted average shares [Abstract]
Basic (in shares)									7,242,212	7,170,701	7,061,404
Effect of dilutive securities [Abstract]
Stock options (in shares)									91,156	151,104	221,858
Diluted (in shares)									7,333,368	7,321,805	7,283,262
Net income per share [Abstract]
Basic (in dollars per share)	$ 0.85	$ 0.69	$ 0.67	$ 0.55	$ 0.37	$ 0.38	$ 0.37	$ 0.47	$ 2.77	$ 1.58	$ 1.61
Diluted (in dollars per share)	$ 0.84	$ 0.69	$ 0.66	$ 0.54	$ 0.36	$ 0.37	$ 0.36	$ 0.46	$ 2.73	$ 1.55	$ 1.56
Stock Options [Member]
Net Income Per Share [Abstract]
Antidilutive securities excluded from earnings per share calculation (in shares)									50,000		20,000