SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES, Stock-Based Compensation (Details)	3 Months Ended		12 Months Ended
	Mar. 31, 2017 USD ($) Plan $ / shares shares	Mar. 31, 2016 USD ($) shares	Dec. 31, 2016 USD ($) $ / shares shares
Share-based Compensation [Abstract]
Number of stock based compensation plans | Plan	1
Additional Disclosures [Abstract]
Proceeds from stock option exercises	$ 258,250	$ 177,250
Closing price of common stock (in dollars per share) | $ / shares	$ 54.80
General and Administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 33,000	$ 33,000
Stock Options [Member]
Stock Options Activity [Roll Forward]
Outstanding, beginning of period (in shares) | shares	297,000
Grants (in shares) | shares	0	0
Exercised (in shares) | shares	(20,000)
Forfeitures or expirations (in shares) | shares	0
Outstanding, end of period (in shares) | shares	277,000		297,000
Exercisable, end of period (in shares) | shares	230,750
Weighted Average Exercise Price [Roll Forward]
Outstanding, beginning of period (in dollars per share) | $ / shares	$ 20.14
Grants (in dollars per share) | $ / shares	0
Exercised (in dollars per share) | $ / shares	12.91
Forfeitures or expirations (in dollars per share) | $ / shares	0
Outstanding, end of period (in dollars per share) | $ / shares	20.66		$ 20.14
Exercisable, end of period (in dollars per share) | $ / shares	$ 18.31
Weighted Average Remaining Contractual Term [Roll Forward]
Outstanding	2 years 11 months 26 days		3 years 1 month 6 days
Grants	0 years
Exercised	0 years
Forfeitures or expirations	0 years
Exercisable	2 years 5 months 19 days
Aggregate Intrinsic Value [Roll Forward]
Outstanding, beginning of period	$ 10,561,380
Grants	0
Exercised	0
Forfeitures or expirations	0
Outstanding, end of period	9,456,330		$ 10,561,380
Exercisable, end of period	8,420,093
Additional Disclosures [Abstract]
Proceeds from stock option exercises	258,250	$ 177,250
Unrecognized compensation cost	$ 234,000
Recognized compensation period	2 years