Earnings per Share Earnings per Share (Details) - shares	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	206,854				206,123				206,854	206,123
Weighted average common shares—basic	45,484,485	45,435,936	45,429,851	45,278,990	45,188,303	45,157,412	45,150,827	44,997,961	45,407,316	45,123,626	44,881,925
Weighted average common shares—diluted	45,484,485	45,760,455	45,726,348	45,654,816	45,188,303	45,499,104	45,418,907	45,400,843	45,407,316	45,123,626	45,269,409
Restricted Shares [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Incremental common shares attributable to dilutive effect of share-based payment arrangements									0	0	245,828
Stock Options [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	206,854				206,123				206,854	206,123	251,667
Incremental common shares attributable to dilutive effect of share-based payment arrangements									0	0	141,656