Capital Stock - Schedule of Common Stock Activity (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Common Stock Activity [Roll Forward]
Beginning balance			$ 211,806
Ending balance	$ 223,412		223,412
Common Stock
Common Stock Activity [Roll Forward]
Beginning balance	218,801	$ 204,171	211,806	$ 194,953
Stock compensation expense	4,044	1,904	10,130	9,595
Stock consideration in acquisition			921	0
Ending balance	223,412	207,315	223,412	207,315
Treasury Cost
Common Stock Activity [Roll Forward]
Beginning balance	303,744	296,870	296,390	296,081
Stock compensation expense	0	0	0	0
Stock consideration in acquisition			0	0
Ending balance	303,500	296,713	303,500	296,713
Restricted and performance stock awards \| Common Stock
Common Stock Activity [Roll Forward]
Restricted and performance stock awards	70	93	2,713	1,594
Restricted and performance stock awards \| Treasury Cost
Common Stock Activity [Roll Forward]
Restricted and performance stock awards	70	93	2,713	1,594
Stock options exercised \| Common Stock
Common Stock Activity [Roll Forward]
Stock compensation expense	637	1,333	2,967	4,124
Stock options exercised \| Treasury Cost
Common Stock Activity [Roll Forward]
Stock compensation expense	292	528	1,194	2,030
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	(118)	(464)	(7,713)	(4,299)
Employee stock purchase program \| Common Stock
Common Stock Activity [Roll Forward]
Employee stock purchase program	0	0	301	237
Employee stock purchase program \| Treasury Cost
Common Stock Activity [Roll Forward]
Employee stock purchase program	$ 0	$ 0	43	43
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			$ (3,347)	$ 0

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Value of all classes of common stock held by shareholders. May be all or portion of the number of common shares authorized. These shares exclude common shares repurchased by the entity and held as treasury shares.

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