REVENUE RECOGNITION (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
REVENUE RECOGNITION [Abstract]
Unearned tuition	$ 25,405	$ 23,453
Revenue recognized included in contract liability	22,800
Disaggregation of Revenue [Abstract]
Total revenues	335,336	293,095
Services Transferred at a Point in Time [Member]
Disaggregation of Revenue [Abstract]
Total revenues	23,079	17,237
Services Transferred over Time [Member]
Disaggregation of Revenue [Abstract]
Total revenues	312,257	275,858
Transportation and Skilled Trades Segment [Member]
Disaggregation of Revenue [Abstract]
Total revenues	240,531	207,434
Transportation and Skilled Trades Segment [Member] | Services Transferred at a Point in Time [Member]
Disaggregation of Revenue [Abstract]
Total revenues	17,393	12,519
Transportation and Skilled Trades Segment [Member] | Services Transferred over Time [Member]
Disaggregation of Revenue [Abstract]
Total revenues	223,138	194,915
Healthcare and Other Professions Segment [Member]
Disaggregation of Revenue [Abstract]
Total revenues	94,805	85,661
Healthcare and Other Professions Segment [Member] | Services Transferred at a Point in Time [Member]
Disaggregation of Revenue [Abstract]
Total revenues	5,686	4,718
Healthcare and Other Professions Segment [Member] | Services Transferred over Time [Member]
Disaggregation of Revenue [Abstract]
Total revenues	$ 89,119	$ 80,943