Goodwill and Intangible Assets (Schedule of Goodwill) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2020
Goodwill [Line Items]
Balance at March 31,	$ 4,108,792	$ 3,795,325
Acquisitions		346,327
Dispositions		(51,136)
Goodwill impairment			$ (561,164)
Effects of foreign currency	4,254	15,583
Adjustments	(142)	2,693
Balance at March 31,	4,112,904	4,108,792	3,795,325
Software and Analytics [Member]
Goodwill [Line Items]
Balance at March 31,	1,758,302	1,770,118
Acquisitions		22,341
Dispositions		(51,136)
Effects of foreign currency	4,254	15,583
Adjustments	(142)	1,396
Balance at March 31,	1,762,414	1,758,302	1,770,118
Network Solutions [Member]
Goodwill [Line Items]
Balance at March 31,	1,970,739	1,645,831
Acquisitions		323,986
Dispositions
Effects of foreign currency
Adjustments		922
Balance at March 31,	1,970,739	1,970,739	1,645,831
Technology-Enabled Services [Member]
Goodwill [Line Items]
Balance at March 31,	379,752	379,376
Acquisitions
Dispositions
Effects of foreign currency
Adjustments		376
Balance at March 31,	$ 379,752	$ 379,752	$ 379,376