GOODWILL AND OTHER INTANGIBLE ASSETS, Other Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Mar. 31, 2020
Other Intangible Assets [Abstract]
Gross carrying amount	$ 87,844		$ 87,844		$ 73,391
Accumulated amortization	(46,216)		(46,216)		(38,927)
Net carrying amount	41,628		41,628		34,464
Total amortization expense for other intangible assets	2,300	$ 2,600	7,300	$ 7,500
Systems Management and Planning, Inc. ("SMP") [Member]
Other Intangible Assets [Abstract]
Intangible assets acquired	14,270		14,270
Customer Relationships and Other Intangibles [Member]
Other Intangible Assets [Abstract]
Gross carrying amount	77,307		77,307		63,006
Accumulated amortization	(39,371)		(39,371)		(33,000)
Net carrying amount	37,936		$ 37,936		30,006
Customer Relationships and Other Intangibles [Member] | Minimum [Member]
Other Intangible Assets [Abstract]
Estimated useful life			5 years
Customer Relationships and Other Intangibles [Member] | Maximum [Member]
Other Intangible Assets [Abstract]
Estimated useful life			10 years
Capitalized Software Development [Member]
Other Intangible Assets [Abstract]
Gross carrying amount	10,537		$ 10,537		10,385
Accumulated amortization	(6,845)		(6,845)		(5,927)
Net carrying amount	3,692		$ 3,692		$ 4,458
Capitalized Software Development [Member] | Minimum [Member]
Other Intangible Assets [Abstract]
Estimated useful life			5 years
Customer Relationships [Member] | Systems Management and Planning, Inc. ("SMP") [Member]
Other Intangible Assets [Abstract]
Estimated useful life			7 years
Intangible assets acquired	$ 14,300		$ 14,300