Share-Based Payments (Share Options) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Payment Arrangement, Expense	$ 9,300	$ 8,400	$ 7,700
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Balance at beginning of year (in shares)	5,514
Granted (in shares)	0	0	0
Expired (in shares)	(1,187)
Exercised (in shares)	(4,327)
Balance at end of year (in shares)	0	5,514
Weighted Average Exercise Price at beginning of year	$ 9.91
Weighted Average Exercise Price, Expired	9.91
Weighted Average Exercise Price, Exercised	$ 9.91
Weighted Average Exercise Price at end of year		$ 9.91
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Total Intrinsic Value	$ 108	$ 29	$ 67
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Abstract]
Stock-based compensation expense	$ 9,271	$ 8,354	$ 7,745
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested, Number of Shares	0	0	0
Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share Based Compensation Arrangement By Share Based Payment Award, Exercisable Period	5 years
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	3 years
Share Based Compensation Arrangement By Share Based Payment Award, Maximum Term	10 years

Share Based Compensation Arrangement By Share Based Payment Award, Exercise Period

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Share Based Compensation Arrangement By Share Based Payment Award, Maximum Term

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Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Abstract]

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Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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Amount of noncash expense for share-based payment arrangement.

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Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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Number of options or other stock instruments for which the right to exercise has lapsed under the terms of the plan agreements.

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Gross number of share options (or share units) granted during the period.

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Number of options outstanding, including both vested and non-vested options.

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

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options of the plan that expired.

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Number of options vested.

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Number of share options (or share units) exercised during the current period.

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