Capital Stock - Schedule of Common Stock Activity (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Common Stock Activity [Roll Forward]
Beginning balance	$ 229,127
Ending balance	232,167
Common Stock
Common Stock Activity [Roll Forward]
Beginning balance	229,127	$ 211,806
Stock compensation expense	3,522	2,745
Ending balance	232,167	213,099
Treasury Cost
Common Stock Activity [Roll Forward]
Beginning balance	303,566	296,390
Stock compensation expense	0	0
Ending balance	328,081	300,919
Restricted and performance stock awards | Common Stock
Common Stock Activity [Roll Forward]
Restricted and performance stock awards	2,239	2,411
Restricted and performance stock awards | Treasury Cost
Common Stock Activity [Roll Forward]
Restricted and performance stock awards	2,239	2,411
Stock options exercised | Common Stock
Common Stock Activity [Roll Forward]
Stock compensation expense	1,757	959
Stock options exercised | Treasury Cost
Common Stock Activity [Roll Forward]
Stock compensation expense	976	506
Treasury shares purchased | Common Stock
Common Stock Activity [Roll Forward]
Treasury shares purchased	0	0
Treasury shares purchased | Treasury Cost
Common Stock Activity [Roll Forward]
Treasury shares purchased	(7,617)	(7,446)
Share repurchase program | Common Stock
Common Stock Activity [Roll Forward]
Treasury shares purchased	0	0
Share repurchase program | Treasury Cost
Common Stock Activity [Roll Forward]
Treasury shares purchased	$ (20,113)	$ 0