XML 34 R7.htm IDEA: XBRL DOCUMENT v3.8.0.1
Consolidated Statements of Stockholders' Equity (Parenthetical) - $ / shares
 12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Dividend reinvestment plan, shares 28,607 38,741 50,013
Stock purchase and compensation plans, shares 635,521 720,323 863,426
Dividends to stockholders, per share $ 0.66 $ 0.61 $ 0.57
Acquisition of treasury stock, shares 136,205 152,595 147,461
Preferred stock, par value per share $ 0 $ 0 $ 0
Preferred stock, shares authorized 5,000,000 5,000,000 5,000,000
Preferred stock, shares issued 0 0 0
Series A Preferred Stock [Member]      
Preferred stock, par value per share $ 0 $ 0 $ 0
Preferred stock, shares authorized 300,000 300,000 300,000