Income Taxes - Reconciliation of the Provision for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Income tax expense computed at statutory rate	$ 17,872	$ 20,981	$ 46,538
Increases (decreases) resulting from:
State income taxes, net of federal tax benefit	4,902	1,936	3,661
Federal jobs credits	(3,164)	(5,006)	(4,193)
Tax exempt interest	(399)	(384)	(568)
Stock-based compensation	298	(1,179)	(4,632)
United States Tax Reform - remeasurement of deferred taxes	0	0	3,719
Other, net	1,006	38	214
Tax provision	$ 20,515	$ 16,386	$ 44,739

Effective Income Tax Rate Reconciliation, Increases (Decreases) [Abstract]

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Amount of difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying domestic federal statutory income tax rate to pretax income (loss) from continuing operation, attributable to expense for award under share-based payment arrangement. Excludes expense determined to be nondeductible upon grant or after for award under share-based payment arrangement.

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

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Amount 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 increase (decrease) in the income tax rates.

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Amount 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 noncontrolling interest income (loss) exempt from income taxes.

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