Income Taxes (Unrecognized Tax Benefits) (Details) - USD ($)	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Summary of activities related to unrecognized tax benefits
Balance at the beginning of the period	$ 16,765,000	$ 20,950,000
Additions to tax positions related to prior years	207,000	648,000
Subtractions to tax positions related to prior years	(1,720,000)	(497,000)
Subtractions to tax positions as a result of the lapse of the statute of limitations	(2,908,000)	(4,336,000)
Balance at the end of the period	12,344,000	16,765,000
Unrecognized tax benefits that, if recognized, would reduce annual effective tax rate	10,600,000	15,000,000.0
Unrecognized tax benefits, interest accrued	0	0	$ 0
Unrecognized tax benefits, penalties accrued	0	$ 0	$ 0
Expected decrease in unrecognized tax benefits during next fiscal year	$ 0

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

No definition available.

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- Definition

The amount of the unrecognized tax benefit of a position taken for which it is reasonably possible that the total amount thereof will significantly increase or decrease within twelve months of the balance sheet date.

+ References

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- Definition

Amount of unrecognized tax benefits.

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Amount of decrease in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.

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Amount of statutory penalties accrued for a tax position claimed or expected to be claimed by the entity, in its tax return.

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Amount of increase in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.

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Amount of interest expense accrued for an underpayment of income taxes.

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Amount of decrease in unrecognized tax benefits resulting from lapses of applicable statutes of limitations.

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The total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate.

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