Major classes of assets and liabilities held for sale (Details 2) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018	Jun. 30, 2018
Current assets:
Total current assets held for sale	$ 428	$ 430	$ 572
Noncurrent assets:
Total noncurrent assets held for sale	2,087	2,087	3,998
Current liabilities:
Total current liabilities held for sale	6,217	4,001	11,713
Discontinued operations, held-for-sale or disposed of by sale
Current assets:
Receivables, net	428	430	572
Income taxes receivable (a)	0	0	1,689
Total current assets held for sale	428	430	2,261
Noncurrent assets:
Net property, plant and equipment	0	0	1,236
Deferred income taxes	1,926	1,926	2,637
Other	161	161	162
Total noncurrent assets held for sale	2,087	2,087	4,035
Total assets held for sale	2,515	2,517	6,296
Current liabilities:
Accounts payable	82	80	0
Taxes payable	3,114	1,451	10,656
Other accrued liabilities	3,021	2,470	2,746
Total current liabilities held for sale	6,217	4,001	13,402
Noncurrent liabilities:
Deferred income taxes (b)	0	0	37
Total noncurrent liabilities held for sale	0	0	37
Total liabilities held for sale	$ 6,217	$ 4,001	$ 13,439