Capital Stock (Tables)

12 Months Ended

Dec. 31, 2019

Capital Stock [Abstract]

Summary of Common Share Activity

A summary of common share activity for the years ended December 31 follows (in shares):

	2019		2018		2017
Common shares outstanding at January 1	135,173,948		134,275,609		139,840,228
Shares repurchased	(106,388	)	(92,167	)	(6,157,010	)
Shares issued upon exercise of employee stock options	70,000		—		299,050
Restricted stock issued to employees, net of forfeitures	416,695		958,672		269,025
Shares issued to non-employee directors	23,623		31,834		24,316
Common shares outstanding at December 31	135,577,878		135,173,948		134,275,609