Basis of Presentation (Stock-Based Compensation) (Details) - USD ($)	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Tax benefit from equity based awards	$ 611,000	$ 888,000
Options granted (in shares)	0	0
Intrinsic value for the total of all options exercised	$ 231,000
Cash received from options exercised	$ 121,000	$ 102,000
Options vested during period (in shares)	0	0
2017 and 2018 RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation, period before change in control	6 months
Prior to 2009
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Typical options expiration period after date of grant	10 years
Time-based RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation, award vesting periods	3 years	3 years
Performance-Based RSUs \| Period One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation, award vesting periods	1 year
Performance-Based RSUs \| Period Two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation, award vesting periods	3 years
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation costs	$ 1,900,000	$ 1,700,000
Share-based unrecognized compensation costs	6,100,000
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation costs	0	$ 0
Share-based unrecognized compensation costs	$ 0
Stock Options \| Prior to 2009
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation, award vesting periods	5 years
Stock Options \| Period One \| Prior to 2009
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation, award vesting periods	3 years
Stock Options \| Period Two \| Prior to 2009
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation, award vesting periods	4 years
Stock Options \| Period Three \| Prior to 2009
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation, award vesting periods	5 years
Long-Term Incentive Plan 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares for issuance under future awards (in shares)	459,893
Long-Term Incentive Plan 2012 \| Time-based RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity instruments other than options, granted (in shares)	52,153	55,665
Long-Term Incentive Plan 2012 \| Performance-Based RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation, vesting percentage after change in control	100.00%
Long-Term Incentive Plan 2012 \| Performance-Based RSUs \| 2017 and 2018 RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation, vesting percentage after change in control	100.00%
Share-based compensation, vesting period after change in control	24 months
Long-Term Incentive Plan 2012 \| Performance-Based RSUs \| Period One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity instruments other than options, granted (in shares)	18,988	27,570
Long-Term Incentive Plan 2012 \| Performance-Based RSUs \| Period Two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity instruments other than options, granted (in shares)	16,108	9,032
Long-Term Incentive Plan 2012 \| RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity instruments other than options, granted (in shares)	0	0

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Share-based Compensation Arrangement by Share-based Payment Award, Options Expiration Period After Date of Grant

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Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

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Unrecognized cost of unvested share-based compensation awards.

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Amount of cash inflow from exercise of stock options granted under share-based compensation arrangement.

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

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Number of options vested.

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