Income Taxes - Expense (benefit) reconciliation (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended	12 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Income Taxes
Statutory federal income tax rate (as a percent)			21.00%		21.00%
Tax at the federal statutory rate	$ 5,273	$ 2,869	$ 4,847	$ 3,424
State income taxes (net of federal benefit)	884	601	813	717
Tax credits	(251)		(251)
Other	1	(36)	3	(46)
Total income tax (benefit) expense	$ 5,907	$ 3,434	$ 5,412	$ 4,095

Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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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 other adjustments.

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