ACQUISITIONS AND DISPOSITIONS - Dispositions (Details) - Disposal Group, Held-for-sale or Disposed of by Sale, Not Discontinued Operations - Systems Engineering Group, Inc. - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	6 Months Ended	12 Months Ended
	Dec. 31, 2020	Mar. 31, 2021	Sep. 30, 2020	Dec. 18, 2020
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration received from business dispositions				$ 15,000
Revenue from disposed business	$ 7,000		$ 31,000
Gain (adjustment) on sale of SEG business		$ 5,291
Gain, net of tax, from business dispositions		$ 5,251
Gain per share from business dispositions		$ 0.10