SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES, Stock-Based Compensation (Details)	3 Months Ended		6 Months Ended			12 Months Ended
	Jun. 30, 2018 USD ($) $ / shares shares	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($) Plan $ / shares shares		Jun. 30, 2017 USD ($)	Dec. 31, 2017 USD ($) $ / shares shares	Jun. 29, 2018 $ / shares
Share-Based Compensation [Abstract]
Number of stock based compensation plans | Plan			1
Additional Disclosures [Abstract]
Proceeds from stock option exercises			$ 860,050	[1]	$ 258,250
Closing price of common stock (in dollars per share) | $ / shares							$ 44.86
General and Administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 63,000	$ 33,000	$ 96,000		67,000
Stock Options [Member]
Weighted Average Grant Date Fair Value [Abstract]
Weighted average grant date fair value (in dollars per share) | $ / shares			$ 18.00
Assumptions Used in Valuation of Stock Options Granted [Abstract]
Risk-free interest rate, minimum			2.62%
Risk-free interest rate, maximum			2.81%
Expected term of option			6 years 3 months
Expected stock price volatility, minimum			39.60%
Expected stock price volatility, maximum			39.70%
Expected dividend yield			0.00%
Stock Options Activity [Roll Forward]
Outstanding, beginning of period (in shares) | shares			232,000
Grants (in shares) | shares			31,500
Exercised (in shares) | shares			(55,000)
Forfeitures or expirations (in shares) | shares			0
Outstanding, end of period (in shares) | shares	208,500		208,500			232,000
Exercisable, end of period (in shares) | shares	169,500		169,500
Weighted Average Exercise Price [Roll Forward]
Outstanding, beginning of period (in dollars per share) | $ / shares			$ 21.56
Grants (in dollars per share) | $ / shares			41.79
Exercised (in dollars per share) | $ / shares			15.64
Forfeitures or expirations (in dollars per share) | $ / shares			0
Outstanding, end of period (in dollars per share) | $ / shares	$ 26.18		26.18			$ 21.56
Exercisable, end of period (in dollars per share) | $ / shares	$ 22.77		$ 22.77
Weighted Average Remaining Contractual Term [Roll Forward]
Outstanding			3 years 4 months 13 days			2 years 6 months 7 days
Grants			0 years
Exercised			0 years
Forfeitures or expirations			0 years
Exercisable			2 years 14 days
Aggregate Intrinsic Value [Roll Forward]
Outstanding, beginning of period			$ 5,050,990
Grants			0
Exercised			1,454,650
Forfeitures or expirations			0
Outstanding, end of period	$ 3,895,465		3,895,465			$ 5,050,990
Exercisable, end of period	3,744,550		3,744,550
Additional Disclosures [Abstract]
Proceeds from stock option exercises			860,000		$ 258,000
Unrecognized compensation cost	$ 611,000		$ 611,000
Recognized compensation period			3 years 3 months 22 days

[1] As of January 1, 2018, the Company adopted the requirements of ASC 606 using the modified retrospective adoption method, and as a result, there is a lack of comparability of certain amounts to the prior periods presented. See Note 2 for additional discussion.