REVENUE RECOGNITION (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
REVENUE RECOGNITION [Abstract]
Unearned tuition	$ 21,682		$ 21,682		$ 25,405
Revenue recognized included in contract liability			24,400
Disaggregation of Revenue [Abstract]
Total revenues	82,142	$ 80,464	164,697	$ 158,461
Services Transferred at a Point in Time [Member]
Disaggregation of Revenue [Abstract]
Total revenues	4,973	6,348	9,763	11,200
Services Transferred over Time [Member]
Disaggregation of Revenue [Abstract]
Total revenues	77,169	74,116	154,934	147,261
Transportation and Skilled Trades Segment [Member]
Disaggregation of Revenue [Abstract]
Total revenues	57,973	56,965	116,758	112,636
Transportation and Skilled Trades Segment [Member] | Services Transferred at a Point in Time [Member]
Disaggregation of Revenue [Abstract]
Total revenues	3,434	5,065	6,845	8,585
Transportation and Skilled Trades Segment [Member] | Services Transferred over Time [Member]
Disaggregation of Revenue [Abstract]
Total revenues	54,539	51,900	109,913	104,051
Healthcare and Other Professions Segment [Member]
Disaggregation of Revenue [Abstract]
Total revenues	24,169	23,499	47,939	45,825
Healthcare and Other Professions Segment [Member] | Services Transferred at a Point in Time [Member]
Disaggregation of Revenue [Abstract]
Total revenues	1,539	1,283	2,918	2,615
Healthcare and Other Professions Segment [Member] | Services Transferred over Time [Member]
Disaggregation of Revenue [Abstract]
Total revenues	$ 22,630	$ 22,216	$ 45,021	$ 43,210