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Consolidated Statement of Shareholders' Equity (Parenthetical) - USD ($) $ in Thousands | 3 Months Ended
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Sep. 30, 2019 | Jun. 30, 2019 | Mar. 31, 2019 | Sep. 30, 2018 | Jun. 30, 2018 | Mar. 31, 2018
Statement of Stockholders' Equity [Abstract] |  |  |  |  |  |
Adjustment to pension benefit liability, taxes | $ 4 | $ 5 | $ 4 | $ 10 | $ 11 | $ 10

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