REVENUE RECOGNITION (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
REVENUE RECOGNITION [Abstract]
Unearned tuition	$ 17,573		$ 17,573		$ 23,411
Revenue recognized included in contract liability			22,200
Disaggregation of Revenue [Abstract]
Total revenues	62,470	$ 63,569	132,511	$ 126,833
Services Transferred at a Point in Time [Member]
Disaggregation of Revenue [Abstract]
Total revenues	2,977	3,646	6,549	6,801
Services Transferred over Time [Member]
Disaggregation of Revenue [Abstract]
Total revenues	59,493	59,923	125,962	120,032
Transportation and Skilled Trades Segment [Member]
Disaggregation of Revenue [Abstract]
Total revenues	42,915	44,028	91,971	88,354
Transportation and Skilled Trades Segment [Member] | Services Transferred at a Point in Time [Member]
Disaggregation of Revenue [Abstract]
Total revenues	2,038	2,487	4,536	4,568
Transportation and Skilled Trades Segment [Member] | Services Transferred over Time [Member]
Disaggregation of Revenue [Abstract]
Total revenues	40,877	41,541	87,435	83,786
Healthcare and Other Professions Segment [Member]
Disaggregation of Revenue [Abstract]
Total revenues	19,555	19,541	40,540	38,479
Healthcare and Other Professions Segment [Member] | Services Transferred at a Point in Time [Member]
Disaggregation of Revenue [Abstract]
Total revenues	939	1,159	2,013	2,233
Healthcare and Other Professions Segment [Member] | Services Transferred over Time [Member]
Disaggregation of Revenue [Abstract]
Total revenues	$ 18,616	$ 18,382	$ 38,527	$ 36,246