Reconciliation of income and expenses (Details 3) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income (loss) from discontinued operations	$ 1,509	$ (118)	$ 26	$ 85
Discontinued operations, held-for-sale or disposed of by sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Operating revenues	230	61	298	201
Operating expenses	(1,760)	216	264	825
Operating income (loss)	1,990	(155)	34	(624)
Other income	0	0	0	12
Interest expense	0	0	0	575
Income (loss) from discontinued operations before income taxes	1,990	(155)	34	(1,187)
Income taxes	481	(37)	8	(1,272)
Income (loss) from discontinued operations	$ 1,509	$ (118)	$ 26	$ 85

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