Income Taxes - Reconciliation between Federal Statutory Income Tax Rate and Effective Tax Rate (Detail) |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|
| Income Tax Disclosure [Abstract] | |||
| Federal statutory income tax rate | 35.00% | 35.00% | 35.00% |
| State taxes, net of federal tax benefits | 6.64% | 7.04% | 8.32% |
| Tax-exempt municipal securities | (0.24%) | (0.26%) | (0.26%) |
| Tax credit - federal | (2.37%) | (2.50%) | (2.51%) |
| Federal rate adjustment, net of federal benefit of state | 4.18% | 0.00% | 0.00% |
| Other | (0.58%) | (2.48%) | 0.95% |
| Effective tax rate | 42.63% | 36.80% | 41.50% |
| X | ||||||||||
- Definition Effective Income Tax Rate Reconciliation Bargain Purchase Gain No definition available.
|
| X | ||||||||||
- Definition Effective Income Tax Rate Reconciliation Federal Tax Credits No definition available.
|
| X | ||||||||||
- Definition Effective Income Tax Rate Reconciliation Municipal Securities Tax Benefit No definition available.
|
| X | ||||||||||
- Definition State Income Taxes Net Of Federal Income Tax Benefit No definition available.
|
| X | ||||||||||
- Definition Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Percentage of domestic federal statutory tax rate applicable to pretax income (loss). Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- 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://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- References No definition available.
|