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Income Taxes - Additional Information (Detail) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Income Tax Expense Benefit [Line Items] |  |  |
Interest expense, domestic deposits | $ 24.0 | $ 40.1 | $ 65.8
Net unrecognized tax benefits | 9.5 | 9.4 |
Accrued interest and penalties related to unrecognized tax benefits | $ 3.0 | 3.1 |
Open tax year | 2011 2012 |  |
Deferred tax liabilities | $ 495.1 | 490.8 |
Net operating loss carryforwards | $ 36.1 | 37.2 |
Net operating loss carryforward expiration year | 2023 |  |
Undistributed earnings of foreign subsidiaries | $ 658.9 | 574.0 |
Deferred income taxes | 1,085.8 | 945.6 |
Deferred tax assets included due to deferral of payroll taxes | 12.9 |  |
State Tax Credits [Member] |  |  |
Income Tax Expense Benefit [Line Items] |  |  |
Deferred tax credits | $ 15.0 |  |
Deferred tax credits expiration year | 2025 |  |
HR One [Member] |  |  |
Income Tax Expense Benefit [Line Items] |  |  |
Deferred income taxes |  |  | $ 2.9
General Business and Other Tax Credits [Member] |  |  |
Income Tax Expense Benefit [Line Items] |  |  |
Deferred tax credits | $ 983.0 |  |
Deferred tax credits expiration year | 2034 |  |
Noncurrent Liabilities [Member] |  |  |
Income Tax Expense Benefit [Line Items] |  |  |
Deferred tax liabilities | $ 106.9 | $ 127.5 |

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