INCOME TAXES - Components of Deferred Taxes (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Deferred tax assets:
Provisions for doubtful accounts	$ 751	$ 879
Inventory costs capitalized for tax purposes	157	177
Inventory valuation reserves	331	652
Sales return reserves	218	190
Deductible expenses, primarily employee-benefit related	745	713
Accrued compensation	2,662	2,999
State tax liability	110	235
Revenue deferral	565	797
Other	1,076	1,276
Compensation under non-statutory stock option agreements	499	565
State tax loss carryforwards	618	505
Federal benefit for uncertain state tax positions	480	641
Total gross deferred tax assets	8,212	9,629
Less: Valuation allowance	(485)	(383)
Net deferred tax assets	7,727	9,246
Deferred tax liabilities:
Goodwill and other intangibles	(17,776)	(15,868)
Property and equipment	(9,553)	(7,084)
Total gross deferred tax liabilities	(27,329)	(22,952)
Net deferred tax liability	(19,602)	(13,706)
Current deferred tax assets		7,909
Noncurrent deferred tax liability	(19,602)	(21,615)
Net deferred tax liability	$ (19,602)	$ (13,706)