Provision For Income Taxes (Reconciliation) (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Provision For Income Taxes
Pre-tax net book income (loss)	$ (50,940)	$ 15,881
Texas Margin Tax	126	267
Return to accrual	76	9
Valuation allowance		(86)
Provision for income taxes	$ 202	$ 190
Effective income tax rate	(0.40%)	1.20%

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

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Amount of income (loss) from continuing operations, including income (loss) from equity method investments, before deduction of income tax expense (benefit), and income (loss) attributable to noncontrolling interest.

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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 revisions of previously reported income tax expense (benefit).

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