Discontinued Operations - income (loss) (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Discontinued Operation, Income Statement Disclosures [Abstract]
Revenues		$ 0		$ 893
Cost of revenues		0		(534)
Operating and other expenses		0		(673)
Gain on disposal of discontinued operations		24		1,251
Income (loss) from discontinued operations before income taxes	$ 0	24	$ 0	937
Income tax (benefit) expense	0	(10)	0	(883)
Income (loss) from discontinued operations	$ 0	$ 34	$ 0	$ 1,820

Amount before tax of gain (loss) not previously recognized resulting from the disposal of a discontinued operation.

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Amount of tax expense (benefit) related to a discontinued operation. Includes, but is not limited to, tax expense (benefit) related to income (loss) from operations during the phase-out period, tax expense (benefit) related to gain (loss) on disposal, tax expense (benefit) related to gain (loss) for reversal of write-down (write-down) to fair value, less cost to sell, and tax expense (benefit) related to adjustments of a prior period gain (loss) on disposal.

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