Earnings per Common Share Earning per Common Share - Reconciliation of Weighted Average Number of Common Shares Outstanding (Details) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Earnings Per Share [Abstract]
Weighted average common shares outstanding – basic (in shares)	144,948	70,049	138,438	70,012
Dilutive effect of share-based awards (in shares)	2,610	0	2,730	0
Equity forward contract (in shares)	68	0	23	0
Weighted average common shares outstanding – diluted (in shares)	147,626	70,049	141,191	70,012