Income Taxes - Schedule of Differences in Federal Income Tax Expense and State Tax Expense from Statutory Federal and State Rates (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Tax Disclosure [Abstract]
Federal taxes calculated at statutory rate	$ 5,897	$ 4,547	$ 17,467	$ 16,086
Increase (decrease) resulting from:
State taxes, net of federal benefit	1,187	528	3,873	1,879
Benefit of equity based compensation	(115)	(134)	(866)	(309)
Municipal interest income, net of interest disallowance	(213)	(351)	(621)	(1,093)
Bank owned life insurance	(13)	(22)	(38)	(64)
Stock offering costs			141
Other	(41)	34	22	102
Total	$ 6,702	$ 4,602	$ 19,978	$ 16,601
Federal taxes calculated at statutory rate, percentage	21.00%	35.00%	21.00%	35.00%
Increase (decrease) resulting from:
State taxes, net of federal benefit, percentage	4.20%	4.10%	4.60%	4.10%
Benefit of equity based compensation, percentage	(0.40%)	(1.00%)	(1.00%)	(0.70%)
Municipal interest income, net of interest disallowance	(0.80%)	(2.70%)	(0.80%)	(2.40%)
Bank owned life insurance, percentage	(0.00%)	(0.20%)	(0.10%)	(0.10%)
Stock offering costs, percentage			0.20%	0.00%
Other, percentage	(0.10%)	0.20%	0.10%	0.20%
Income tax expense, as reported, percentage	23.90%	35.40%	24.00%	36.10%

Effective income tax rate reconciliation, municipal interest income net of interest disallowance, percent.

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Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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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 life insurance expense.

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