Annual report pursuant to Section 13 and 15(d)

Stock Compensation (Valuation Assumptions Of Stock Option Plan) (Details)

v3.8.0.1
Stock Compensation (Valuation Assumptions Of Stock Option Plan) (Details)
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Stock Compensation [Abstract]    
Expected volatility 30.40% 29.50%
Risk free interest rate 2.00% 1.50%
Expected holding period 6 years 6 years
Dividend yield 3.70% 9.10%