v3.25.1
Customer Funds - Gross Unrealized Losses and Related Fair Value of Investment (Detail)
$ in Millions
Mar. 31, 2025
USD ($)
Debt Securities, Available-for-sale [Line Items]  
Less than 12 months, Unrealized Losses $ (2.0)
Less than 12 months, Fair Value 236.9
12 months or more, Unrealized Losses (23.6)
12 months or more, Fair Value 928.0
Total, Unrealized Losses (25.6)
Total, Fair Value 1,164.9
U.S. Government and Agencies Securities [Member]  
Debt Securities, Available-for-sale [Line Items]  
Less than 12 months, Unrealized Losses (1.4)
Less than 12 months, Fair Value 135.4
12 months or more, Unrealized Losses (16.7)
12 months or more, Fair Value 410.4
Total, Unrealized Losses (18.1)
Total, Fair Value 545.8
Canadian and Provincial Government Securities [Member]  
Debt Securities, Available-for-sale [Line Items]  
Less than 12 months, Unrealized Losses 0.0
Less than 12 months, Fair Value 0.0
12 months or more, Unrealized Losses (2.0)
12 months or more, Fair Value 173.4
Total, Unrealized Losses (2.0)
Total, Fair Value 173.4
Corporate Debt Securities [Member]  
Debt Securities, Available-for-sale [Line Items]  
Less than 12 months, Unrealized Losses (0.3)
Less than 12 months, Fair Value 57.2
12 months or more, Unrealized Losses (3.7)
12 months or more, Fair Value 253.4
Total, Unrealized Losses (4.0)
Total, Fair Value 310.6
Asset-backed Securities [Member]  
Debt Securities, Available-for-sale [Line Items]  
Less than 12 months, Unrealized Losses (0.1)
Less than 12 months, Fair Value 17.9
12 months or more, Unrealized Losses (0.4)
12 months or more, Fair Value 42.0
Total, Unrealized Losses (0.5)
Total, Fair Value 59.9
Mortgage-backed Securities [Member]  
Debt Securities, Available-for-sale [Line Items]  
Less than 12 months, Unrealized Losses (0.2)
Less than 12 months, Fair Value 22.9
12 months or more, Unrealized Losses (0.3)
12 months or more, Fair Value 7.4
Total, Unrealized Losses (0.5)
Total, Fair Value 30.3
Other Securities [Member]  
Debt Securities, Available-for-sale [Line Items]  
Less than 12 months, Fair Value 3.5
12 months or more, Unrealized Losses (0.5)
12 months or more, Fair Value 41.4
Total, Unrealized Losses (0.5)
Total, Fair Value $ 44.9