Capital Stock and Equity Awards - Commons Shares (Details) - shares	9 Months Ended
	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, shares outstanding	29,582,656	29,257,566
Common stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of common shares issued during period	325,090
Common stock, shares outstanding	29,582,656	29,257,566	29,116,496	28,941,547
Options | Common stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of common shares issued during period	300,168
RSUs | Common stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of common shares issued during period	24,922