LONG-TERM OBLIGATIONS (Detail Textuals) - First Tennessee Bank National Association ("First Tennessee") - Unsecured revolving credit facility (the "Credit Facility") - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Oct. 31, 2017	Dec. 31, 2016	Jun. 22, 2016	Jun. 11, 2015	Dec. 21, 2011	Apr. 06, 2010
Line of Credit Facility [Line Items]
Revolving credit facility				$ 50,000	$ 30,000	$ 25,000	$ 20,000
Description of reference rate basis	LIBOR Market Index Rate plus 1.50
Variable interest rate in addition to reference rate	1.50%
Interest rate	2.73%
Outstanding borrowings under credit facility	$ 20,000		$ 5,000
Non-cancelable operating lease obligations	$ 1,401
Minimum
Line of Credit Facility [Line Items]
Non-usage fee for current loan agreement in annual amount percentage	0.15%
Maximum
Line of Credit Facility [Line Items]
Non-usage fee for current loan agreement in annual amount percentage	0.35%
Subsequent Event
Line of Credit Facility [Line Items]
Outstanding borrowings under credit facility		$ 20,000