Common Stock Issued and Outstanding (Tables)

12 Months Ended

Dec. 31, 2017

Stockholders' Equity and Common Stock Issued and Outstanding [Abstract]

Activity in Number of Shares of Common Stock Issued and Outstanding

(Number of shares outstanding)	2017	2016	2015
Beginning of year	172,202,177	172,034,711	177,499,513
Stock options exercised  1	–	–	15,575
Restricted stock awards  1	368,132	158,504	478,549
Employee stock purchase and thrift plans	2,564	8,962	8,387
Treasury shares purchased	–	–	(5,967,313)
End of year	172,572,873	172,202,177	172,034,711

1 Shares issued upon exercise of stock options and award of restricted stock are less than the amount reflected in Note J  due to withholdings for statutory income taxes owed upon issuance of shares.