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Stock-Based Compensation (Textuals) (Details) | 12 Months Ended |
--- | --- | ---
Dec. 31, 2018 USD ($) plan $ / shares shares | Dec. 31, 2017 USD ($) $ / shares shares | Dec. 31, 2016 USD ($) $ / shares shares | Dec. 31, 2015 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Other charges | $ | $ 3,800,000 | $ 0 | $ 200,000 |
Shares available for grant/issuance | 3,710,483 |  |  |
Unrecognized compensation expense for all nonvested awards | $ | $ 19,100,000 |  |  |
Weighted average period for recognition | 1 year 8 months |  |  |
Employee Stock Option [Member] |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Awards, expiration period | 10 years |  |  |
Number of shares reduced for each award granted | 1 |  |  |
Stock Appreciation Rights (SARs) [Member] |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Vesting period | 4 years |  |  |
Awards, expiration period | 10 years |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding, Number | 39,819 | 51,368 | 116,087 | 232,930
Award Types Other than Stock Options and Stock Appreciation Rights [Member] |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Number of shares reduced for each award granted | 2.5 |  |  |
Performance-Vesting Shares [Member] |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Granted at target level | 102,307 | 92,045 | 115,035 |
Granted at target level | $ / shares | $ 90.45 | $ 84.01 | $ 60.47 |
Employee Stock Purchase Plan (ESPP) [Member] |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Shares available for grant/issuance | 3,900,000 |  |  |
Percentage of current market price for sales to eligible employees | 85.00% |  |  |
Limitation on payroll deductions of employee's base salary, percent | 25.00% |  |  |
Limitation on payroll deductions of employee's base salary, amount | $ | $ 25,000 |  |  |
Maximum number of shares per employee | 2,000 |  |  |
Maximum number of shares per employee, per year |  | 8,000 |  |
Purchases of shares | 55,669 | 56,218 | 60,839 |
Restricted Stock [Member] |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Granted at target level | 15,942 | 0 | 1,393 |
Granted at target level | $ / shares | $ 96.77 |  | $ 71.79 |
Annual Incentive Plan [Member] |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Granted at target level | 1,500 | 1,800 | 2,400 |
Vesting period | 4 years |  |  |
Granted at target level | $ / shares | $ 93.00 | $ 86.93 | $ 59.64 |
Performance-Vesting Units [Member] |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Granted at target level | 560 | 598 | 419 |
Granted at target level | $ / shares | $ 89.64 | $ 83.47 | $ 59.64 |
Minimum [Member] | Performance-Vesting Shares [Member] |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Actual payout range | 0.00% |  |  |
Minimum [Member] | Performance-Vesting Units [Member] |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Actual payout range | 0.00% |  |  |
Maximum [Member] | Performance-Vesting Shares [Member] |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Actual payout range | 200.00% |  |  |
Maximum [Member] | Performance-Vesting Units [Member] |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Actual payout range | 200.00% |  |  |
Deferred Compensation Plans [Member] |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Deferred Compensation Arrangement with Individual, Conversion Unit | 1 |  |  |
Number of deferred compensation plans | plan | 2 |  |  |
Number of deferred stock units | 429,777 |  |  |
Number of deferred stock units payable in cash | 24,296 |  |  |
Deferred Compensation Plans [Member] | Non-Employee Directors [Member] |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Granted at target level | 18,824 |  |  |
Granted at target level | $ / shares | $ 87.69 |  |  |

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