Segment Reporting (Revenue and Adjusted EBITDA for each Reportable Segment) (Details) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Segment Reporting Information [Line Items]
Total revenue	$ 694,184
Adjusted EBITDA	196,856
Equity compensation	9,583
Acquisition accounting adjustments	48,540
Acquisition and divestiture-related costs	5,120
Integration and related costs	10,358
Strategic initiatives, duplicative and transition costs	5,080
Severance costs	4,704
Accretion and changes in estimate with related parties, net	5,895
Impairment of long-lived assets and other	6,313
Gain on sale of businesses	(28,095)
Contingent consideration	(2,450)
Other non-routine, net	2,677
EBITDA adjustments	67,725
EBITDA	129,131
Interest expense	62,667
Depreciation and amortization	138,541
Amortization of capitalized software developed for sale	78
Income (loss) before income tax provision (benefit)	(72,155)	$ (39,701)
Postage and Eliminations [Member]
Segment Reporting Information [Line Items]
Total revenue	27,063
Purchase Accounting Adjustment [Member]
Segment Reporting Information [Line Items]
Total revenue	(55,000)
Software and Analytics [Member]
Segment Reporting Information [Line Items]
Total revenue	391,589
Adjusted EBITDA	143,932
Network Solutions [Member]
Segment Reporting Information [Line Items]
Total revenue	142,826
Adjusted EBITDA	70,503
Technolgy-Enabled Services [Member]
Segment Reporting Information [Line Items]
Total revenue	187,706
Adjusted EBITDA	(17,579)
Postage [Member]
Segment Reporting Information [Line Items]
Total revenue	45,772
Postage [Member] | Postage and Eliminations [Member]
Segment Reporting Information [Line Items]
Total revenue	$ 45,772