Income Taxes - Summary of Reconciliation Between the Statutory Tax Rate and Actual Effective Tax Rate (Detail) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2018 |
Dec. 31, 2017 |
Dec. 31, 2016 |
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| Income Tax Disclosure [Abstract] | |||
| Statutory tax rate | 21.00% | 35.00% | 35.00% |
| State taxes, net of federal benefit | 1.10% | 0.50% | 0.70% |
| Tax-exempt interest | (2.10%) | (3.30%) | (2.90%) |
| Cash surrender value of life insurance | (0.50%) | (1.10%) | (1.50%) |
| Tax credits | (2.80%) | (2.60%) | (0.90%) |
| TCJA deferred tax corporate rate change | 0.70% | 0.20% | 0.00% |
| Tax Cuts and Jobs Act revaluation of net deferred tax assets | (0.40%) | 15.20% | 0.00% |
| Other items | 0.60% | 0.20% | 0.20% |
| Actual effective tax rate | 17.60% | 44.10% | 30.60% |
| Income tax expense | $ 54.0 | ||
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- Definition Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to changes in the cash surrender value of life insurance policies. No definition available.
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- Definition Effective Income Tax Rate Reconciliation, Tax Cuts and Jobs Act of 2017, Percent No definition available.
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- Definition Tax Cuts and Jobs Act of 2017, Change in Tax Rate, Income Tax Expense (Benefit) No definition available.
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- Definition Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Percentage of domestic federal statutory tax rate applicable to pretax income (loss). Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to changes in the income tax rates. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to other adjustments. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations applicable to state and local income tax expense (benefit), net of federal tax expense (benefit). Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to tax credits. Including, but not limited to, research credit, foreign tax credit, investment tax credit, and other tax credits. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to income (loss) exempt from income taxes. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- References No definition available.
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