FEDERAL AND STATE INCOME TAXES - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
FEDERAL AND STATE INCOME TAXES
Operating lease liabilities	$ 7,170	$ 2,981
Accrued expenses not deductible until paid	6,105	5,215
Goodwill and intangible assets	1,264	1,426
Finance lease obligations	794	287
Net operating loss carry forwards	298	1,643
Revenue recognition	238	201
Allowance for doubtful accounts	225	168
Equity incentive compensation	204	188
Other	5	60
Total deferred tax assets	16,303	12,169
Deferred tax liabilities:
Tax over book depreciation	(30,315)	(30,941)
Operating leases - right of use assets	(7,075)	(2,959)
Prepaid expenses deductible when paid	(2,327)	(2,095)
Other		(191)
Total deferred tax liabilities	(39,717)	(36,186)
Net deferred tax liabilities	$ (23,414)	$ (24,017)