Stock-Based Compensation Assumptions Used (Details) - Stock Options |
6 Months Ended | |||
|---|---|---|---|---|
Jun. 30, 2017 | ||||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||
| Weighted average volatility | 21.00% | [1] | ||
| Dividend yield | 0.50% | |||
| Minimum [Member] | ||||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||
| Risk-free interest rate | 1.93% | |||
| Expected years until exercise | 5 years 6 months | |||
| Maximum [Member] | ||||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||
| Risk-free interest rate | 2.26% | |||
| Expected years until exercise | 8 years | |||
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