SEGMENT REPORTING, Reportable Segment Information (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2020 USD ($) Segment	Dec. 31, 2019 USD ($)	Mar. 31, 2020 USD ($)
SEGMENT REPORTING [Abstract]
Number of business segments | Segment			2
Reportable Segment Information [Abstract]
Net sales	$ 427,604	$ 428,991	$ 1,215,716	$ 1,221,928
Cost of Sales [Abstract]
Cost of sales	329,453	325,295	920,046	922,562
Gross profit	98,151	103,696	295,670	299,366
Selling, general, and administrative	65,390	73,090	201,746	209,400
Depreciation and amortization	3,143	3,647	10,000	10,667
Interest and financing costs	355	694	1,179	1,898
Operating expenses	68,888	77,431	212,925	221,965
Operating income	29,263	26,265	82,745	77,401
Other income (expense)	813	997	1,095	912
Earnings before tax	30,076	27,262	83,840	78,313
Net Sales [Abstract]
Contracts with customers	413,079	406,607	1,161,411	1,167,073
Financing and other	14,525	22,384	54,305	54,855
Net sales	427,604	428,991	1,215,716	1,221,928
Selected Financial Data - Statement of Cash Flow [Abstract]
Depreciation and amortization	4,302	5,140	13,762	15,217
Purchases of property, equipment and operating lease equipment	960	2,321	4,227	7,209
Selected Financial Data - Balance Sheet [Abstract]
Total assets	1,125,954	952,608	1,125,954	952,608	$ 909,113
Product [Member]
Reportable Segment Information [Abstract]
Net sales	375,512	378,569	1,066,408	1,077,667
Cost of Sales [Abstract]
Cost of sales	297,514	293,209	827,111	832,135
Net Sales [Abstract]
Net sales	375,512	378,569	1,066,408	1,077,667
Service [Member]
Reportable Segment Information [Abstract]
Net sales	52,092	50,422	149,308	144,261
Cost of Sales [Abstract]
Cost of sales	31,939	32,086	92,935	90,427
Net Sales [Abstract]
Net sales	52,092	50,422	149,308	144,261
Technology Segment [Member]
Reportable Segment Information [Abstract]
Net sales	415,570	410,628	1,176,153	1,176,881
Net Sales [Abstract]
Contracts with customers	411,175	404,918	1,157,519	1,163,184
Financing and other	4,395	5,710	18,634	13,697
Net sales	415,570	410,628	1,176,153	1,176,881
Operating Segments [Member] | Technology Segment [Member]
Reportable Segment Information [Abstract]
Net sales	415,570	410,628	1,176,153	1,176,881
Cost of Sales [Abstract]
Cost of sales	327,249	323,066	913,794	915,936
Gross profit	88,321	87,562	262,359	260,945
Selling, general, and administrative	62,377	67,759	190,519	197,615
Depreciation and amortization	3,115	3,619	9,916	10,555
Interest and financing costs	0	0	266	0
Operating expenses	65,492	71,378	200,701	208,170
Operating income	22,829	16,184	61,658	52,775
Net Sales [Abstract]
Contracts with customers	411,175	404,918	1,157,519	1,163,184
Financing and other	4,395	5,710	18,634	13,697
Net sales	415,570	410,628	1,176,153	1,176,881
Selected Financial Data - Statement of Cash Flow [Abstract]
Depreciation and amortization	3,311	3,691	10,444	10,974
Purchases of property, equipment and operating lease equipment	959	786	4,060	3,461
Selected Financial Data - Balance Sheet [Abstract]
Total assets	887,684	733,174	887,684	733,174
Operating Segments [Member] | Technology Segment [Member] | Product [Member]
Reportable Segment Information [Abstract]
Net sales	363,478	360,206	1,026,845	1,032,620
Cost of Sales [Abstract]
Cost of sales	295,310	290,980	820,859	825,509
Net Sales [Abstract]
Net sales	363,478	360,206	1,026,845	1,032,620
Operating Segments [Member] | Technology Segment [Member] | Service [Member]
Reportable Segment Information [Abstract]
Net sales	52,092	50,422	149,308	144,261
Cost of Sales [Abstract]
Cost of sales	31,939	32,086	92,935	90,427
Net Sales [Abstract]
Net sales	52,092	50,422	149,308	144,261
Operating Segments [Member] | Financing Segment [Member]
Reportable Segment Information [Abstract]
Net sales	12,034	18,363	39,563	45,047
Cost of Sales [Abstract]
Cost of sales	2,204	2,229	6,252	6,626
Gross profit	9,830	16,134	33,311	38,421
Selling, general, and administrative	3,013	5,331	11,227	11,785
Depreciation and amortization	28	28	84	112
Interest and financing costs	355	694	913	1,898
Operating expenses	3,396	6,053	12,224	13,795
Operating income	6,434	10,081	21,087	24,626
Net Sales [Abstract]
Contracts with customers	1,904	1,689	3,892	3,889
Financing and other	10,130	16,674	35,671	41,158
Net sales	12,034	18,363	39,563	45,047
Selected Financial Data - Statement of Cash Flow [Abstract]
Depreciation and amortization	991	1,449	3,318	4,243
Purchases of property, equipment and operating lease equipment	1	1,535	167	3,748
Selected Financial Data - Balance Sheet [Abstract]
Total assets	238,270	219,434	238,270	219,434
Operating Segments [Member] | Financing Segment [Member] | Product [Member]
Reportable Segment Information [Abstract]
Net sales	12,034	18,363	39,563	45,047
Cost of Sales [Abstract]
Cost of sales	2,204	2,229	6,252	6,626
Net Sales [Abstract]
Net sales	12,034	18,363	39,563	45,047
Operating Segments [Member] | Financing Segment [Member] | Service [Member]
Reportable Segment Information [Abstract]
Net sales	0	0	0	0
Cost of Sales [Abstract]
Cost of sales	0	0	0	0
Net Sales [Abstract]
Net sales	$ 0	$ 0	$ 0	$ 0