SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Earnings Per Common Shares (Details) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Earnings Per Common Share (EPS)
Weighted average common shares outstanding	2,007,613	2,018,649
Weighted average common and common equivalent shares outstanding	2,007,613	2,018,649
Stock Options.
Anti-dilutive securities
Options not included in weighted average common shares outstanding	2,250	4,750
Weighted average exercise price of options not included in weighted average common shares outstanding (in dollars per share)	$ 8.91	$ 10.58
Outstanding options to purchase shares of common stock not included, anti-dilutive	15,918	11,418
Weighted average exercise price of options, anti-dilutive (in dollars per share)	$ 14.51	$ 15.99