Amount of amortization of the restricted stock bonus.

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Percentage of financial goals.

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Percentage of target opportunity for awards to vest.

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Unrecognized cost of unvested share-based compensation awards.

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Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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The cash outflow for cost incurred directly with the issuance of an equity security.

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The percentage rate used to calculate dividend payments on preferred stock.

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The aggregate amount of noncash, equity-based employee remuneration. This may include the value of stock or unit options, amortization of restricted stock or units, and adjustment for officers' compensation. As noncash, this element is an add back when calculating net cash generated by operating activities using the indirect method.

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Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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Weighted average remaining contractual term for equity-based awards excluding options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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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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No definition available.

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The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested).

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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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The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

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Fair value of options vested. Excludes equity instruments other than options, for example, but not limited to, share units, stock appreciation rights, restricted stock.

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Stock-based Compensation (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
	Dec. 14, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized for issuance		1,500,000
Percentage of dividend	20.00%
Share-Based Compensation		$ 3,006	$ 2,339	$ 1,959
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted		35,000	31,277	47,779
Shares granted, weighted average grant date market value			$ 49.55	$ 38.13
Amortization of restricted stock bonus		$ 1,571	$ 1,743	$ 1,712
Total unrecognized compensation expense, weighted average period		9 months
Total fair value of shares vested		$ 1,112	$ 1,389	$ 1,500
Fair value of granted shares per share		$ 49.79
Performance-based restricted shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted		35,602	30,388
Vesting period		3 years	3 years
Fair value of granted shares per share		$ 48.67	$ 49.33
Expense incurred to grant shares		$ 745	$ 690
Percentage of financial goal		144.00%	132.00%
Performance-based restricted shares [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of target opportunity for awards to vest		0.00%	0.00%
Performance-based restricted shares [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of target opportunity for awards to vest		150.00%	150.00%
SARs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation expense		$ 0
Total intrinsic value of options exercised		$ 1,110	$ 892
Average remaining contractual term		3 years 6 months	5 years 11 days
Outstanding, Aggregate Intrinsic Value		$ 5,468	$ 7,291
Share-Based Compensation		$ 0