Annual report pursuant to Section 13 and 15(d)

Per Share Data (Narrative) (Details)

v3.8.0.1
Per Share Data (Narrative) (Details) - shares
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Earnings Per Share [Abstract]      
Antidilutive securities excluded from computation of earnings per share, amount (in shares) 32,501,007 41,191,772 57,494,385