Financial Data by Segment - Schedule of Financial Data Segment Reporting Information (Details) $ in Millions	3 Months Ended								12 Months Ended
	Jun. 30, 2021 USD ($)	Mar. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Sep. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)	Mar. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2021 USD ($) Segment	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | Segment									2
Revenues	$ 1,531.6	$ 1,389.8	$ 1,054.9	$ 1,017.4	$ 1,361.9	$ 1,249.9	$ 968.7	$ 948.6	$ 4,993.7	$ 4,529.0	$ 4,362.2
Earnings (loss) before income taxes	336.4	$ 216.9	$ 69.4	$ 73.6	294.8	$ 210.5	$ 10.5	$ 63.8	696.2	579.5	607.3
Assets	8,119.8				4,889.8				8,119.8	4,889.8	3,880.7
Capital expenditures									51.9	62.7	50.6
Depreciation and amortization									67.4	73.8	85.2
Amortization of acquired intangibles and purchased intellectual property									153.7	122.9	87.4
Amortization of other assets									113.6	102.6	87.4
Investor Communication Solutions
Segment Reporting Information [Line Items]
Revenues									3,867.5	3,491.3	3,468.3
Global Technology and Operations
Segment Reporting Information [Line Items]
Revenues									4,993.7	4,529.0	4,362.2
Operating Segments | Investor Communication Solutions
Segment Reporting Information [Line Items]
Revenues									3,867.5	3,491.3	3,468.3
Earnings (loss) before income taxes									605.6	464.1	506.2
Assets	2,517.6				2,484.4				2,517.6	2,484.4	2,155.6
Capital expenditures									42.3	35.9	34.5
Depreciation and amortization									36.9	42.9	54.3
Amortization of acquired intangibles and purchased intellectual property									86.0	81.7	70.6
Amortization of other assets									39.4	30.9	36.4
Operating Segments | Investor Communication Solutions | Restatement Adjustment
Segment Reporting Information [Line Items]
Revenues											(42.8)
Earnings (loss) before income taxes											(2.2)
Operating Segments | Global Technology and Operations
Segment Reporting Information [Line Items]
Revenues									1,258.1	1,174.2	996.3
Earnings (loss) before income taxes									223.3	245.0	212.5
Assets	5,162.3				1,734.2				5,162.3	1,734.2	1,423.6
Capital expenditures									3.0	5.3	6.5
Depreciation and amortization									12.7	12.0	11.9
Amortization of acquired intangibles and purchased intellectual property									66.2	39.7	16.3
Amortization of other assets									58.0	54.8	45.7
Operating Segments | Global Technology and Operations | Restatement Adjustment
Segment Reporting Information [Line Items]
Revenues											42.8
Earnings (loss) before income taxes											2.2
Other
Segment Reporting Information [Line Items]
Revenues									0.0	0.0	0.0
Earnings (loss) before income taxes									(153.0)	(146.3)	(130.9)
Assets	439.9				671.1				439.9	671.1	301.6
Capital expenditures									6.7	21.6	9.6
Depreciation and amortization									17.8	18.9	19.0
Amortization of acquired intangibles and purchased intellectual property									1.5	1.5	0.5
Amortization of other assets									16.1	16.8	5.3
Foreign Currency Exchange
Segment Reporting Information [Line Items]
Revenues									(131.9)	(136.4)	(102.4)
Earnings (loss) before income taxes									20.3	16.8	19.4
Assets	$ 0.0				$ 0.0				0.0	0.0	0.0
Capital expenditures									0.0	0.0	0.0
Depreciation and amortization									0.0	0.0	0.0
Amortization of acquired intangibles and purchased intellectual property									0.0	0.0	0.0
Amortization of other assets									$ 0.0	$ 0.0	$ 0.0