Earnings per Share Earnings per Share (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Weighted average common shares—basic	45,592,075	45,920,307	45,585,445	45,850,137
Weighted average common shares—diluted	45,828,315	46,200,757	45,910,249	46,215,047
Restricted Stock Units (RSUs) [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Incremental common shares attributable to share-based payment arrangements	174,571	176,658	253,796	267,620
Stock Options [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Incremental common shares attributable to share-based payment arrangements	61,669	103,792	71,008	97,290