Annual report pursuant to Section 13 and 15(d)

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

v3.7.0.1
Stock Compensation (Valuation Assumptions Of Stock Option Plan) (Details)
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Stock Compensation [Abstract]      
Expected volatility 29.50% 30.70% 31.40%
Risk free interest rate 1.50% 1.60% 2.70%
Expected holding period 6 years 6 years 6 years
Dividend yield 9.10% 5.70% 5.20%