Capital Stock - Schedule of Common Stock Activity (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Common Stock Activity [Roll Forward]
Beginning balance			$ 229,127
Ending balance	$ 233,786		233,786
Common Stock
Common Stock Activity [Roll Forward]
Beginning balance	232,167	$ 213,099	229,127	$ 211,806
Stock compensation expense	(830)	(3,340)	(4,352)	(6,086)
Ending balance	233,786	218,801	233,786	218,801
Treasury Cost
Common Stock Activity [Roll Forward]
Beginning balance	328,081	300,919	303,566	296,390
Stock compensation expense	0	0	0	0
Ending balance	327,997	303,744	327,997	303,744
Restricted and performance stock awards | Common Stock
Common Stock Activity [Roll Forward]
Restricted and performance stock awards	226	232	2,464	2,643
Restricted and performance stock awards | Treasury Cost
Common Stock Activity [Roll Forward]
Restricted and performance stock awards	226	232	2,464	2,643
Stock options exercised | Common Stock
Common Stock Activity [Roll Forward]
Stock compensation expense	(677)	(1,372)	(2,433)	(2,330)
Stock options exercised | Treasury Cost
Common Stock Activity [Roll Forward]
Stock compensation expense	(330)	(395)	(1,307)	(902)
Treasury shares purchased | Common Stock
Common Stock Activity [Roll Forward]
Treasury shares purchased	0	0	0	0
Treasury shares purchased | Treasury Cost
Common Stock Activity [Roll Forward]
Treasury shares purchased	(524)	(148)	(8,141)	(7,595)
Share repurchase program | Common Stock
Common Stock Activity [Roll Forward]
Treasury shares purchased	0	0	0	0
Share repurchase program | Treasury Cost
Common Stock Activity [Roll Forward]
Treasury shares purchased	0	(3,347)	(20,113)	(3,347)
Stock consideration in acquisition | Common Stock
Common Stock Activity [Roll Forward]
Stock compensation expense	0	921	0	921
Stock consideration in acquisition | Treasury Cost
Common Stock Activity [Roll Forward]
Stock compensation expense	0	0	0	0
Employee stock purchase program | Common Stock
Common Stock Activity [Roll Forward]
Stock compensation expense	338	301	338	301
Employee stock purchase program | Treasury Cost
Common Stock Activity [Roll Forward]
Stock compensation expense	$ 52	$ 43	$ 52	$ 43