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Deferred tax reconciliation (Details 5) - USD ($) $ in Thousands | 12 Months Ended
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Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Income Tax Disclosure [Abstract] |  |  |
Change in net deferred income tax liability from the preceding table | $ 9,515 |  |
Deferred taxes associated with other comprehensive loss | 1,817 |  |
Excess deferred income tax amortization | (12,517) |  |
Other | (616) |  |
Deferred income taxes | $ (1,801) | $ 63,415 | $ 59,735

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