REVENUE RECOGNITION (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
REVENUE RECOGNITION [Abstract]
Unearned tuition	$ 22,744		$ 22,744		$ 25,405
Revenue recognized included in contract liability			24,600
Disaggregation of Revenue [Abstract]
Total revenues	91,813	$ 89,059	256,510	$ 247,520
Services Transferred at a Point in Time [Member]
Disaggregation of Revenue [Abstract]
Total revenues	7,710	7,821	17,474	19,022
Services Transferred over Time [Member]
Disaggregation of Revenue [Abstract]
Total revenues	84,103	81,238	239,036	228,498
Transportation and Skilled Trades Segment [Member]
Disaggregation of Revenue [Abstract]
Total revenues	67,329	64,950	184,087	177,586
Transportation and Skilled Trades Segment [Member] | Services Transferred at a Point in Time [Member]
Disaggregation of Revenue [Abstract]
Total revenues	6,059	6,203	12,904	14,788
Transportation and Skilled Trades Segment [Member] | Services Transferred over Time [Member]
Disaggregation of Revenue [Abstract]
Total revenues	61,270	58,747	171,183	162,798
Healthcare and Other Professions Segment [Member]
Disaggregation of Revenue [Abstract]
Total revenues	24,484	24,109	72,423	69,934
Healthcare and Other Professions Segment [Member] | Services Transferred at a Point in Time [Member]
Disaggregation of Revenue [Abstract]
Total revenues	1,651	1,618	4,570	4,234
Healthcare and Other Professions Segment [Member] | Services Transferred over Time [Member]
Disaggregation of Revenue [Abstract]
Total revenues	$ 22,833	$ 22,491	$ 67,853	$ 65,700