Earnings Per Common Share (Dilutive Common Share Equivalents) (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Weighted-average common shares outstanding, basic (in shares)	74,715,592	73,272,085	74,362,211	72,613,221
Effect of dilutive securities (in shares)	4,656,899	0	3,952,508	0
Weighted-average common shares outstanding, diluted (in shares)	79,372,491	73,272,085	78,314,719	72,613,221
Restricted stock units
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Effect of dilutive securities (in shares)	1,616,072	0	1,083,237	0
Stock options
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Effect of dilutive securities (in shares)	3,040,827	0	2,869,271	0
Employee stock purchase program
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Effect of dilutive securities (in shares)	0	0	0	0