Reconciliation of income and expenses (Details 3) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income (loss) from discontinued operations	$ (1,320)	$ (273)	$ (1,483)	$ 203
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	37	75	67	140
Operating expenses	1,778	435	2,023	609
Operating loss	(1,741)	(360)	(1,956)	(469)
Other income	0	0	0	12
Interest expense	0	0	0	575
Loss from discontinued operations before income taxes	(1,741)	(360)	(1,956)	(1,032)
Income taxes	(421)	(87)	(473)	(1,235)
Income (loss) from discontinued operations	$ (1,320)	$ (273)	$ (1,483)	$ 203