Shareholders' Equity - Common Stock and Treasury Stock Period Activity (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Common Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, Beginning	254,613	253,594	253,209
Stock based compensation plans, net	1,103	1,019	385
Acquisition of Treasury stock	0
Cancellation of Treasury stock	(24,026)
Balance, Ending	231,690	254,613	253,594
Treasury Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, Beginning	0	0	0
Stock based compensation plans, net	0	0	0
Acquisition of Treasury stock	26,093
Cancellation of Treasury stock	(24,026)
Balance, Ending	2,067	0	0