Income Taxes - Income Tax Expense (Benefit), Continuing Operations (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current Income Tax Expense (Benefit)
Federal	$ 66	$ 622	$ 0
State	984	1,221	1,297
Foreign	460	662	697
Current Income Tax Expense (Benefit)	1,510	2,505	1,994
Deferred Income Tax Expense (Benefit)
Federal	1,857	6,432	9,779
State	178	425	1,324
Foreign	(444)	845	(698)
Deferred Income Tax Expense (Benefit)	1,591	7,702	10,405
Income tax provision	$ 3,101	$ 10,207	$ 12,399

Amount of current federal tax expense (benefit) pertaining to income (loss) from continuing operations.

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