Income Taxes (Schedule of Curent and Deferred Taxes) (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016
Income Taxes [abstract]
Current taxes on profit for the year	$ 34,940	$ 29,791
Changes in estimates related to prior years	(77)	(728)
Total current tax expense (income) and adjustments for current tax of prior periods	34,863	29,063
Origination and reversal of temporary differences	5,194	594
Changes in estimates related to prior years	165	217
Effect of changes in tax rates	(1,576)	(622)
Deferred tax expense (income)	3,783	189
Total tax expense	$ 38,646	$ 29,252

Income Taxes [abstract].

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Adjustments of tax expense (income) recognised in the period for current tax of prior periods.

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Adjustments of tax expense (income) recognised in the period for the deferred tax of prior periods.

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The amount of income taxes payable (recoverable) in respect of the taxable profit (tax loss) for a period.

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The amount of current tax expense (income) and adjustments for the current tax of prior periods. [Refer: Current tax expense (income); Adjustments for current tax of prior periods]

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The amount of tax expense (income) relating to changes in deferred tax liabilities and deferred tax assets. [Refer: Deferred tax assets; Deferred tax liabilities]

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The amount of deferred tax expense or income relating to tax rate changes or the imposition of new taxes. [Refer: Deferred tax expense (income)]

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The aggregate amount included in the determination of profit (loss) for the period in respect of current tax and deferred tax that relate to continuing operations. [Refer: Continuing operations [member]; Current tax expense (income); Deferred tax expense (income)]

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